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Achondroplasia

This is part of Rare diseases.

Diagnosis: Achondroplasia

Synonyms: --


Publication date: 2013-11-01
Version: 1.1

ICD 10 code

Q77.4

The disease

Achondroplasia is a hereditary condition associated with very short stature. It primarily affects the limbs, while the trunk is only slightly shorter than normal.

The condition has been known for thousands of years. The term achondroplasia (a = no, chondros = cartilage, plasia = formation) was used for the first time in 1878 by French physician M J Parrot. However, the term is not strictly correct as cartilage formation in achondroplasia is generally normal and impaired growth is caused by abnormalities in the growth zones of the skeleton.

Several hundred inherited skeletal dysplasias are currently recognised. Some affect the whole skeleton while others affect specific parts of the body. In the Swedish Board of Health and Welfare’s Database of Rare Diseases there is information on other skeletal dysplasias including chondrodysplasia punctata, diastrophic dysplasia, congenital spondyloepiphyseal dysplasia, multiple epiphyseal dysplasia, pseudoachondroplasia and late-onset spondyloepiphyseal dysplasia.

Occurrence

Achondroplasia is thought to be equally common in all the world’s populations, affecting approximately five children in every 100,000 newborns. In Sweden, this means that approximately five children a year are born with achondroplasia, making a total of between 300 and 400 people in the country with the diagnosis.

Cause

Achondroplasia is caused by a mutation in a gene which controls production of (codes for) a receptor for fibroblast growth factor 3. This gene, FGFR3, is located on the short arm of chromosome 4 (4p16.3).

The mutation produces a change to the growth factor receptor, causing it to signal for a slow down in bone growth. It is thought that the receptor is found in all growth zones of the skeleton. The reason that the zones of the arms and legs are particularly affected is not known.

Heredity

The inheritance pattern of achondroplasia is autosomal dominant. This means that one of the parents has the disease, and so has one normal gene and one mutated gene. Sons and daughters of this parent have a 50 per cent risk of inheriting the disease. Children who do not inherit the mutated gene do not have the disease and do not pass it on.

Figure: Autosomal dominant inheritance

In the great majority of people, the syndrome is caused by a new mutation. This means that the genetic mutation occurs for the first time in an individual and is not inherited from either parent. Consequently, parents with a child with a new mutation generally do not have an increased risk of having another child with the disorder. However, the new genetic mutation will be hereditary and an adult with this mutation risks passing on the mutated gene to his/her children. The pattern of inheritance is then autosomal dominant.

If two people with achondroplasia have a child, there is a 25 per cent risk that the child will receive two copies of the mutated gene (a homozygote for this particular gene) causing significant skeletal abnormalities. Since these abnormalities include an abnormally small rib cage, the child will not survive the neonatal period. There is a 50 per cent risk that the child receives one copy of the mutation and so inherits the condition, while 25 per cent of children inherit two normal genes and do not have achondroplasia.

Symptoms

Characteristics of achondroplasia include short stature, short limbs, large head with prominent forehead and midfacial hypoplasia, where the the middle of the face is underdeveloped. Skeletal abnormalities including narrow vertebral canals for the spinal cord and medulla oblongata (the lower half of the brainstem) can cause orthopaedic and neurological complications. Hands and fingers are extremely short.

The neonatal period and the first two years of life

At birth, children with achondroplasia are of normal size. During the first months their growth may be normal, but then it slows abruptly. Growth of the lower extremities becomes very limited while the trunk develops more normally.

The circumference of the head is unusually large, making it heavy and hard to balance. The circulation of cerebrospinal fluid is sometimes impaired and in some children may lead to hydrocephalus.

Neurological symptoms

The base of the skull and the spinal canal are underdeveloped, often compressing the spinal cord and medulla oblongata. Space in the posterior cranial fossa is more limited than normal. The foramen magnum, the large opening in the occipital bone of the cranium, is often so narrow that the circulation of cerebrospinal fluid is affected and the medulla oblongata is pinched. Severe compression can cause symptoms in the form of abnormal reflexes or unusual muscle weakness in the legs. It is important to be aware that the medulla oblongata and spinal cord can be affected without this resulting in clear neurological symptoms.

The canals which conduct the cranial nerves (cranial nerves IX, X, XI and XII) in the base of the skull may be narrow, causing poor coordination or weakness in the throat or respiratory muscles.

During the neonatal period and in their first years children may experience increased levels of sweating. It is therefore advisable to allow the child to sleep in a cool place and without too many clothes.

Breathing

The mid-face area and its internal structures are underdeveloped. The upper respiratory passages are narrow, causing abnormalities such as abnormal pauses in breathing (obstructive apnea). This may be exacerbated by enlarged tonsils and adenoids. The rib cage may be narrow and constricted, resulting in laboured breathing.

The respiratory centre in the medulla oblongata may be affected by constrictions in the foramen magnum and the spinal column, with the associated risk of causing abnormal pauses in breathing (central apnea) and a reduced ability to exhale carbon dioxide. Respiratory problems often diminish as the child grows and respiratory passages become larger.

Ears

Because of space constrictions in the midface region and its associated internal structures, passages between the inner ear and the pharynx are also smaller than usual, increasing the risk of both acute and chronic middle-ear inflammation (otitis media). Hearing may also be affected, and speech development delayed.

Development

The development of motor skills is nearly always delayed and is associated with mild to moderate muscle weakness which gradually normalises during the first years of life. Head control is also delayed, and the majority of children with the condition are unable to hold their heads up independently until after seven months of age. Children with achondroplasia start to walk at approximately 18 months and at two and a half years old around 90 per cent of them can walk. The delay is the result of a combination of muscular weakness in the legs, hypermobility of the knee joints and an unusually large, heavy head, which is difficult to balance.

Fine motor skills develop more normally, although the abnormal anatomy of the child’s hands and fingers means that he or she has an unusual grip.

Cognitive abilities are not affected.

Speech development is often delayed by a few months, which may be a result of impaired hearing caused by periods of chronic ear infection (otitis) and possibly also of an impairment of the cranial nerves on the function and movements of the throat.

Orthopaedic abnormalities

Muscle weakness in the trunk, together with abnormalities of the vertebrae, can cause a hump (kyphosis) to form in the part of the spine between the chest and the lumbar region (the thoracolumbar segment) during the first year of life. This abnormality is usually moderate and is most obvious when the child sits, becoming smaller or disappearing when the child lies on its stomach. The kyphosis usually disappears entirely when the child starts to walk. However, it remains in approximately 10 per cent of children with achondroplasia and in some cases becomes more severe.

Most children with achondroplasia have some degree of difficulty when trying to fully extend the arm from the elbow. It is not possible to correct this defect through surgery, but for most children it does not cause major problems. The joints, with the exception of the elbow joints, are hypermobile as a result of lax ligaments and joint capsules. In achondroplasia joint cartilage is normal.

Pre-school and school-age children

Growth

Children with the condition grow very slowly and are usually five standard deviation units below average on the height chart. This means, for example, that a seven year old boy or girl is approximately 25 cms shorter than his or her peers.

Speech development and dental bite

As a result of skeletal facial abnormalities, the palate is often high and narrow. There may also be bite abnormalities (malocclusion). Enlarged tonsils and adenoids can further limit space in the mouth, making speech indistinct.

Orthopaedic abnormalities

From the time they start to walk, children with the condition may develop a clear inward curvature of the spine (lordosis) in the lumbar region. It is often moderate but can sometimes be more pronounced, exacerbating an unusual, waddling, gait. This distinctive gait is caused by anatomical abnormalities of the pelvis and the hips.

Lax joint capsules in the knee and ankles, along with abnormal growth of the tibia, means that the child often develops bow legs during these years. This creates deformities and increases pressure on the joints, which in turn leads to wear and tear damage (arthrosis), although the cartilage itself is normal.

Neurological symtoms

Compression of the spinal cord (spinal stenosis) can cause symptoms in the form of tired back, pain, numbness, tingling in the legs, paralysis and urinary incontinence. This is very common in adults with achondroplasia but may also be found in some young children. Spinal stenosis is mainly a result of the abnormal shape of the vertebrae and the vertebral discs, together with short, narrowly-spaced vertebral arches particularly in the lower lumbar region. This constriction is exacerbated as the intervertebral discs impinge on the spinal canal. Severe kyphosis or lordosis can make the spinal canal even narrower.

Adults

The adult height for women with achondroplasia is on average 125 cms (varying between 115 and 135 cms) and for men 133 cms (varying between 121 and 145 cms). These heights are approximately 42 to 48 centimetres shorter than average. Generally, short stature is the result of short lower limbs, the height of the individual when seated being often only slightly shorter than average and sometimes completely normal.

Despite a noticeable increase in the understanding of medical problems faced by children with achondroplasia, there is little documented information on adults with the condition. In particular, knowledge is lacking concerning how adults with achondroplasia cope with their orthopaedic, respiratory and neurological problems. Knowledge of respiratory and cardiac function in adults is also limited, but mortality in people with achondroplasia is higher than average in individuals of all ages, which is thought to be caused by apnea and circulatory problems.

Compression of the spinal cord causes symptoms in most adults with achondroplasia. With increasing age, the growth of bone spurs on the vertebrae (degenerative spondylosis) further reduces space within the spinal column and the nerves of the spinal cord may be pinched. The narrowest part of the spinal column is usually found in the lumbar region. Compression of the spinal cord (spinal stenosis) can cause symptoms in the form of tired back, pain, numbness, tingling in the legs, paralysis and urinary incontinence.

Up to 40 per cent of people with the condition have impaired hearing, which may be caused by chronic or frequent inflammation of the middle ear.

Breathing and anaesthesia

Chronic, poor, respiration can raise pulmonary pressure and over time may cause pulmonary heart disease (cor pulmonale).

Confined space in the oral cavity and the pharynx may cause problems when anaesthesia is called for. The administration of spinal and epidural anaesthetics prior to surgery may also be more complicated than normal.

Diagnosis

A diagnosis can usually be made at birth on the basis of certain characteristics typical of achondroplasia. These include disproportionately short upper arms and thighs, an unusually large head circumference with midfacial hypoplasia (associated with a prominent forehead and flat nasal bridge). The hands, and sometimes also the feet, are usually short. Fingers are generally short and of similar lengths.

In some children these physical characteristics are less pronounced at birth, and for approximately 20 per cent of infants the diagnosis is made later, during the first year of life or occasionally even later.

In the neonatal period a skeletal X-ray will reveal characteristic signs of achondroplasia including an unusually large skull with a comparatively little base and a small foramen magnum (the opening in the occipital bone of the cranium).The hips are small and square-shaped and the upper part of the acetabulum (a surface of the pelvis which is usually concave) is horizontal. The extremities are short and disproportionately wide. The fibula is longer than the tibia.

The diagnosis can be confirmed by a DNA analysis establishing the presence of the specific mutation in the FGFR3 gene. If this mutation is not identified the condition cannot be achondroplasia and another diagnosis must be made.

Prenatal diagnosis is possible if a routine ultrasound scan indicates achondroplasia or if the mutation has been identified in the family. However, skeletal abnormalities become more apparent during the second trimester. Samples for DNA analysis can be taken first in weeks 10 to 12 of the pregnancy in the case of chorionic villus sampling (CVS), or in weeks 15 to 18 in the case of amniocentesis.

At the time of diagnosis, the family should be offered genetic counselling. Pre-implantation genetic diagnosis (PGD) is possible in combination with in vitro fertilisation (IVF) if one of the parents has achondroplasia.

Treatment/interventions

There is currently no cure for this disease. Treatment therefore focuses on alleviating symptoms and compensating for functional impairments.

Treatment and monitoring

As they are growing, children with achondroplasia require regular examinations and checkups by a number of specialists in order to discover complications as they arise or, if possible, prevent them. It is important that attention is paid to the problems and risks associated with compression of the upper respiratory tract and the canals housing nerves and blood vessels, as well as the orthopaedic and neurological complications associated with achondroplasia. It is thought that these risks may be underestimated as the frequency of unexpected deaths in children under the age of five with the condition is much higher than average.

Care should have a long-term focus and ideally be organized in the form of a single unit with access to relevant specialists in the fields of respiratory physiology, paediatric neurology, neurophysiology, neurosurgery, neuroradiology and orthopaedic surgery. Assessments of urinary and bowel function may be necessary, as may hearing tests.

The neonatal period and first year of life

During the neonatal period the child’s brain should be examined using magnetic resonance imaging (MRI) to assess potential compression of the spinal cord at the foramen magnum and the upper part of the spinal canal. In the case of severe compression affecting the medulla oblongata (the lower half of the brain stem) or the circulation of cerebral fluid, an operation (craniocervical decompression) should be considered to create more space.

During the child’s first year of life the growth of the skull should be frequently monitored. X-ray examinations of the brains of children with achondroplasia usually show slightly enlarged ventricles and increased amounts of fluid around the brain. This may not always be hydrocephalus but if the head measurement continues to expand, an operation to insert a shunt is required. This will lead excessive fluid from the brain via a tube to the abdomen.

The child’s respiratory function should be described and documented during the neonatal period, even if there are no signs that breathing is affected. Examinations often need to be repeated throughout the first year of life and should identify whether the child breathes rapidly, grunts when exhaling, snores, ceases to breathe (sleep apnea) or sleeps in an abnormal position (with head bent back to widen the airways). Retraction (when the baby pulls in the chest at the ribs when inhaling), or an obstructive breathing pattern when exhaling, should also be noted. In addition, it is recommended to monitor pulse rate and oxygen saturation levels in haemoglobin (pulse oximetry), and measure levels of carbon dioxide in exhaled air or in blood (blood gas analysis) during sleep.

If it is clear that respiratory function is affected, a more extensive examination should be performed. This includes a procedure which measures heart frequency and blood gases as well as movements of the ribcage and abdomen, for at least eight hours while the subject is asleep (polysomnography). The examination will confirm whether there is inadequate ventilation (hypoventilation) and show whether abnormalities in breathing are caused by upper respiratory problems (of an obstructive origin) or whether the brain stem is affected (central origin). Rapid breathing may also be caused by a narrow ribcage. Children who cannot exhale sufficient amounts of carbon dioxide may require breathing assistance at night, using either CPAP (Continuous Positive Airway Pressure) or BiPAP (Biphasic Positive Airway Pressure). If impaired respiratory function continues untreated, there is a risk that the child will develop heart-lung disease.

Enlarged tonsils and adenoids increase breathing problems in small children with achondroplasia. Both can be reduced in size through an operation, an adenotonsillotomy. This has a positive effect on breathing. The operation often needs to be repeated after some time. Children with achondroplasia often sleep with their heads bent backwards, which causes their airways to open to the maximum extent. Bending the head forward can sometimes block the airways. Because a child with achondroplasia does not have sufficient control of the head, carrying him or her in a baby sling is not advisable.

In the neonatal period, muscle strength in the legs is usually impaired. If this lack of muscle tone is very severe, or if reflexes in relation to muscle strength are stronger than normal or the child has recurrent stretching reflexes in the foot (foot clonus), a neurologist should carry out an immediate investigation. Neuroradiological investigations can identify a narrow foramen magnum and/or spinal canal. It is important to know that even if these structures are abnormally narrow they do not necessarily cause obvious neurological or respiratory symptoms. It is therefore recommended that all children with achondroplasia have an MRI (magnetic resonance imaging) scan, preferably during the first week of life.

Kyphosis, a condition usually affecting the thoracolumbar region of the spine and most obvious when sitting, generally disappears when the child begins to walk. However, the condition remains in approximately 10 per cent of children, and in some individuals it becomes more severe. These children may require corrective surgery. Where kyphosis persists or increases, an MRI scan (and in some cases neurophysiological examinations) should be carried out to establish whether the spinal cord is being compressed. If kyphosis is severe when sitting and does not disappear when lying on the stomach, the child’s development should be checked at least once every six months. A thorough neurological examination should be carried out as well as an X-ray examination to measure the degree of spinal curvature.

The development of severe kyphosis may be slowed by use of a surgical corset. However, the corset may cause respiratory problems, and the need for help with respiration should be assessed before and after the corset is fitted. In infants with weak musculature there is a risk that the ribcage will become deformed, causing respiratory problems.

Children who do not have sufficient muscle strength in their trunks may require back support when sitting. This may take the form of a specially-made orthosis (an orthopaedic appliance or apparatus). Joint stability in the feet may be improved by using appropriate orthoses and shoes with support for the ankles.

Preschool and school-age children

During the early years it is important that orthopaedic abnormalities and the child’s respiration are monitored regularly. If the child breathes rapidly while at rest, snores, or has an abnormal sleeping position it is important that new investigations are carried out. A decision is necessary as to whether an operation (adenotonsillotomy) would reduce respiratory problems.

In the case of language or speech problems, and with swallowing difficulties, the child should be examined by a speech and language therapist and/or ear specialist. Regular ear examinations and hearing tests should be performed, and grommets (small plastic tubes) may be inserted into the ear.

Abnormalities in the development of the facial skeleton can cause the palate to be unusually high and narrow with bite abnormalities (malocclusions). Dental braces (orthodontic treatment) may be necessary to ensure a normal dental bite.

If the joints of the ankle and knee are at risk of growing out of alignment as a result of bow legs and rotational deformities, an operation may be needed to correct abnormalities by realigning the tibia and femur. Severe outward curvature of the legs may sometimes be prevented by an operation which temporarily locks the growth zones on one side of the leg.

The abnormally narrow spinal canal can cause neurological symptoms already in childhood, in which case an operation to remove vertebral arches in the affected areas may be considered in rare cases. At the same time arthrodesis (artificial induction of joint ossification) may be carried out to reduce the risk of further deterioration and deformity of the spine.

Teenagers and young adults

It may be important for teenagers to receive information on surgical procedures to increase bone length. Internationally, bone extension in cases of achondroplasia has been carried out extensively, although this treatment is not common in Sweden. Surgical procedures to extend bone growth are best performed during childhood or before the person is 25 years of age. Usually the procedure is not carried out before the individual is a teenager or young adult and so can make an informed decision. It is possible to lengthen both the thigh bone and tibia, increasing height by up to 20 cms, or sometimes more. This gruelling period of treatment involves a considerable limitation of mobility for over approximately two years. It is considerably more difficult to lengthen the arms due to the anatomical peculiarities of the nerves of the arms and hands, hence experience of this procedure is limited.

Adults

If there are symptoms of spinal stenosis, in order to assess the degree of compression it is essential that examinations include MRI (magnetic resonance imaging) and CT (computerized tomography) scans of the back, as well as neurophysiological tests of nerve conduction in the spinal cord. Investigations should also include tests of bladder function (urodynamic testing). The most severe compression is usually between the first and fourth lumbar vertebrae (L1-L4), but it may also be present in the thoracic vertebrae. A diagnosis of spinal stenosis should be made in consultation with a spinal surgeon. A laminectomy (a surgical procedure that removes a portion of the vertebral bone) alleviates the problem in many cases.

Monitoring for signs of spinal stenosis should be carried out regularly, every third to fifth year.

As the pelvises of women with achondroplasia are unusually narrow, their babies are usually delivered by caesarian section under general anaesthetic.

Habilitation

The child and family require early contact with a habilitation team made up of professionals with special expertise in how disability affects everyday life, health and development.

Support and treatment take place within the medical, educational, psychological, social and technical fields. Help includes assessment, treatment, the provision of aids, information on the specific disability, and counselling. It also includes information on all available support offered in the community, as well as advice on adjustments to the home environment and other places where the child spends time. The parents and siblings as well as the child should be offered support.

Habilitation is planned to meet specific needs. Habilitation varies over time but always takes place in collaboration with those close to the child or young person. Children with impaired hearing also receive auditory habilitation. The objective of such measures is that the child should become as independent as possible. At the same time that the child undergoes training it is important that home, pre-school and school environments are adjusted as early as possible to meet the needs of the child. Different aids make it easier for the child to participate in activities and develop independence both at home and in other environments.

There are aids for very young children in the form of adjustable supports providing convenient and comfortable seating in pushchairs or at a table. When the child can walk, stools to climb up on, low door handles and light switches and specially-designed toilets and hand basins can help create an environment where the child can develop independence. Similar adjustments should also be made in pre-schools and schools.

When children with achondroplasia are of school age, many of them can manage daily routines with the help of differently-sized stools. Some require help when using the toilets, while others manage by themselves. Many need some kind of help with mobility. Some children have an electric wheelchair; others use a cycle or scooter at school so that they can keep up with their classmates.

Physical training is required to strengthen muscles. Exercise in a swimming pool is useful for children whose heads are large and heavy.

As long as the foramen magnum (the opening in the occipital bone of the cranium) is not too narrow, there are no particular constraints on exercise for older children. If they fall, younger children with achondroplasia cannot protect themselves in the same way as other children by using their arms and legs. For this reason it may be advisable for the youngest children to wear a soft helmet.

In some children speech and language development is delayed in which case they may require help with developing oral motor skills, as well as language training. Difficulties in controlling swallowing, and abnormalities in the oral cavity may cause certain eating problems which require assessment and treatment.

Children and young people of short stature should be treated in a way appropriate to their age and in the same way as their peers. Even when they are very young these children may be aware that they are shorter than their friends of the same age. Some may require continued psychological support as they are growing up. In order for children with achondroplasia to grow into well-adjusted adults it is important that they are not overprotected, but are allowed to be like other children. Both for children with the condition and their families it may be useful to meet other people in the same situation to exchange experiences.

Adults with achonroplasia require continuous, individually-designed habilitation. Adjustments to accommodation are often essential, while special adjustments to a car may also be appropriate.

Occupational guidance may sometimes be needed, as well as adaptations to the work environment. The employment services and the Swedish Social Insurance Agency can provide information and support.

Practical advice

The Association for People of Short Stature in Sweden - DHR (see under, “Organizations for the disabled/patient associations etc.”) have several contacts around Sweden, who can provide information, advice and support. The same apples to RBU’s regional associations. (See under, “Organizations for the disabled/patient associations etc.”)

Some hints from parents

Points to note in younger children up to the age of 6

It may be useful to consider the child’s sitting position, for example when sitting in a car’s child seat, to ensure the child’s airways do not become blocked. Be particularly careful when the child is using a swing. As arms and legs are unusually short the child’s centre of gravity may be affected, causing him or her to fall out of the swing. When using a baby swing there is a risk that small children with achondroplasia can slip through the space meant for a child’s legs, and their heads become stuck. On falling, children also run an increased risk of whiplash and nerve injuries as their necks are weak and their heads are often larger and heavier than normal.

Later, when the child needs to sit up but does not have the strength to do so, seating supports may be useful. After a few simple adjustments they may be used very successfully. They may be used in the child’s pram so that child can see out. It is also possible to attach them to dining chairs, for example when visiting restaurants. For indoor mobility different types of adjustable wheelchairs may be used. A shower support, where the child can be moved from a recumbent to a sitting position, is useful as a child with achondroplasia cannot bend the head backwards without losing balance when his or her hair is being washed.

A special table that helps compensate for unusually short arms may be useful when the child can sit without support. It should be possible to adjust the depth of the chair and the placing of foot supports in, for example, a TrippTrapp chair. It is also possible to add one or two extra supports so the child is able to climb up and down independently. If the chair is fitted with supports of this kind, additional legs should be fitted to ensure the chair does not tip over.

Clothes need to be tailored to the child as he/she grows. Shoes should not weigh too much.

Mobility

When other children stop using a push chair it can be good for children with achondroplasia to change to a wheelchair if they cannot manage to walk for long distances. Some children may require an electric wheelchair.

The school environment

There are many possible ways of making schools’ dining rooms easier to use. Some schools put serving dishes on the tables making it easier for all children, regardless of height, to take their own food. In this way the dining room becomes calmer as there is less coming and going. Other schools have made it possible for children to serve themselves at a lower table, which is also advantageous for younger children of normal height.

National and regional resources in Sweden

Diagnoses are made at regional hospital paediatric clinics.

The skeletal dysplasia team at the Astrid Lindgren Children’s Hospital has wide experience of monitoring children and young people with achondroplasia. Currently (2013) approximately fifty children and young people are being followed up. The team consists of representatives from: respiratory physiology, neurosurgery, neuroradiology, skeletal radiology, paediatric orthopaedics, paediatric endocrinology, physiotherapy, urinary incontinence therapy and clinical genetics. The contact person is research nurse Lo Neumeyer, tel: +46 8 5177 75 81.

Specialists in orofacial issues are to be found at Mun-H-Center, Institute of Odontology
Gothenburg, Medicinaregatan 12A, SE-413 90 Gothenburg, Sweden. Tel: +46 31 750 92 00, fax: +46 31 750 92 01, email: mun-h-center@vgregion.se, www.mun-h-center.se.

Resource personnel

Stockholm: Astrid Lindgren Children’s Hospital, SE-171 76 Stockholm, Sweden. Tel: +46 8 517 777 00. Lars Hagenäs and Eva Horemuzova (paediatric endocrinology), Eva Moström and Stephanie Böhm (orthopaedic surgery), Bengt Gustavsson (neurosurgery), Mikael Mosskin (neuroradiology), Stefan Geiberger (skeletal radiology), Giedre Grigelioniene and Ann Nordgren (clinical genetics).

Gothenburg: The Queen Silvia Children’s Hospital, SE-416 85 Gothenburg, Sweden. Tel: +46 31 343 40 00. Specialist Physician, Annika Reims.

Umeå: Children and Young People’s Centre, Norrlands University Hospital, SE-901 85 Umeå, Sweden. Tel: +46 90 785 00 00. Senior Physician Berit Kriström.

Courses, exchanges of experience, recreation

The Association for People of Short Stature in Sweden - DHR (see address under “Organizations for the disabled/patient associations etc.”), organises annual meetings for families and individuals.

Ågrenska is a national competence centre for rare diseases and its families’ programme arranges stays for children and young people with disabilities and their families. Ågrenska is open to families from the whole of Sweden and focuses particularly on the needs of children and young people with rare diseases. A number of programmes every year are also provided for adults with rare diseases. Information is available from Ågrenska, Box 2058, SE-436 02 Hovås, Sweden. Tel: +46 31 750 91 00, fax: +46 31 91 19 79, email: agrenska@agrenska.se, www.agrenska.se.

Organizations for the disabled/patient associations etc.

RBU, The Swedish National Association for Disabled Children and Young People, St Eriksgatan 44, Box 8026, SE-104 20 Stockholm, Sweden. Tel: +46 8 677 73 00, fax: +46 8 677 73 09, email: info@riks.rbu.se, www.rbu.se

The Association for People of Short Stature in Sweden, DHR, www.fkv.se, email: info@fkv.se. The chair is Gunilla Hyltén-Cavallius, tel: +46 70 351 98 94, email: gunilla.hc@telia.com.

Courses, exchanges of experience for personnel

During the Ågrenska Family Program weeks, training days are organized for personnel working with the children and young people who are participating. Information is available from Ågrenska, Box 2058, SE-436 02 Hovås, Sweden. Tel: +46 31 750 91 00, fax: +46 31 91 19 79, email: agrenska@agrenska.se, www.agrenska.se.

Research and development

At Astrid Lindgren Children’s Hospital in Stockholm research is under way into the connection between muscle strength and gait, using a computerized gait analysis program. It is hoped that gait analysis can be used as an aid in assessing the need for, and the effectiveness of, orthoses. It can also help in judging the need for operations on the legs, including surgical procedures to treat bow legs.

The corrolation of large amounts of data regarding height, weight and physical proportions of children and young peole with achondroplasia is currently (2013) underway at Astrid Lindgren Children’s Hospital. Growth curves for those with the condition are hoped to be ready in 2013.

Increased knowledge of cell biology and the molecular regulation of activity in the skeleton’s growth zones, make medical intervention in childhood to affect poorly performing growth zones theoretically possible. Currently (2013) there are plans to start clinical studies where children with achondroplasia receive treatment with a hormone usually found in the growth zones of the skeleton. However, it will take many years before it is clear whether such therapy is possible and what its effects are on height.

Information material

Short summaries of all the database texts are available as leaflets, in Swedish only. They can be printed out or ordered by selecting the Swedish version, and then clicking on the leaflet icon which will appear under "Mer hos oss" in the column on the right-hand side.

Newsletters from Ågrenska on achondroplasia, no. 414 (2012) and no. 326, (2008). (In Swedish only.) Newsletters are edited summaries of lectures delivered at family and adult visits to Ågrenska. They may be ordered from Ågrenska, Box 2058, SE-436 02 Hovås, Sweden. Tel: +46 31 750 91 00, fax: +46 31 91 19 79, email: agrenska@agrenska.se 
They are also available at www.agrenska.se.

From DHR, the Association for People of Short Stature in Sweden

Kort men inte liten (Pernilla Gesén, Eva Schreiber). In Swedish only. A book on what it is like to be of short stature, aimed mainly at children.

On the Association’s website you will find links to associations in other countries: www.fkv.se.se/lankar.php.

From RBU, the Swedish National Association for Disabled Children and Young People

Barn och ungdomar med kortväxthet. (2010). (Children and adolescents with short stature. In Swedish only). This booklet can be ordered from RBU or downloaded as a pdf. from www.rbu.se.

Books

Doktorn kunde inte riktigt laga mig (Gothia förlag, 2007). In Swedish only. A book about young children, illness and disability by Christina Renlund. ISBN 978-91-7205-553-7.

Literature

BAin MC, Abdullah MA, Ting BL, Skolasky RL, Carlisle ES, Schkrohowsky JG et al. Progression of low back and lower extremity pain in a cohort of patients with achondroplasia. J Neurosurg Spine 2010; 13: 335-340.

Baca KE, Abdullah MA, Ting BL, Schkrohowsky JG, Hoernschemeyer DG, Carson BS et al. Surgical decompression for lumbar stenosis in pediatric achondroplasia. J Pediatr Orthop 2010; 30: 449-454.

Bagley CA, Pindrik JA, Bookland MJ, Camara-Quintana JQ, Carson BS. Cervicomedullary decompression for foramen magnum stenosis in achondroplasia. J Neurosurg 2006; 104: 166-172.

Beals RK, Stanley G. Surgical correction of bowlegs in achondroplasia. J Pediatr Orthop B 2005; 14: 245-249.

Boor R, Fricke G, Brühl K, Spranger J. Abnormal subcortical somatosensory evoked potentials indicate high cervical myelopathy in achondroplasia. Eur J Pediatr 1999; 158: 662-667.

Brühl K, Stoeter P, Wietek B, Schwarz M, Humpl T, Schumacher R et al. Cerebral spinal fluid flow, venous drainage and spinal cord compression in achondroplastic children: impact of magnetic resonance findings for decompressive surgery at the cranio-cervical junction. Eur J Pediatr 2001; 160: 10-20.

Fraser SC, Neubauer PR, Ain MC. The role of arthrography in selecting an osteotomy for the correction of genu varum in pediatric patients with achondroplasia. J Pediatr Orthop B 2011; 20: 14-16.

Hecht JT, Francomano CA, Horton WA, Annegers JF. Mortality in achondroplasia. Am J Hum Genet 1987; 41: 454-464.

Ho NC, Guarnieri M, Brant LJ, Parks SS, Sun B, North M et al. Living with achondroplasia: quality of life evaluation following cervico-medullary decompression. Am J Med Genet A 2004; 131: 163-167.

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Sciubba DM, Noggle JC, Marupudi NI, Bagley CA, Bookland MJ, Carsons BS Sr et al. Spinal stenosis surgery in pediatric patients with achondroplasia. J Neurosurg 2007; 106: 372-378.

Sisk EA, Heatley DG, Borowski BJ, Leverson GE, Pauli RM. Obstructive sleep apnea in children with achondroplasi: surgical and anestethic considerations. Otolaryngol Head Neck Surg 1999; 120: 248-254.

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Database references

OMIM (Online Mendelian Inheritance in Man)
www.ncbi.nlm.nih.gov/omim 
Search: achondroplasia

GeneReviews (University of Washington)
www.genetests.org (select “GeneReviews”, then “Titles”)
Search: achondroplasia

Document information

The Swedish Information Centre for Rare Diseases produced and edited this information material.

The medical expert who wrote the draft of this information material is Associate Professor Lars Hagenäs, The Astrid Lindgren Children’s Hospital, Sweden. Valuable input has been provided by Associate Professor Helena Saraste, Karolinska Institutet, Stockholm.

The relevant organisations for the disabled/patient associations have been given the opportunity to comment on the content of the text.

An expert group on rare diseases, affiliated with the University of Gothenburg, approved the material prior to publication.

Date of publication: 2013-11-01
Version: 1.1
Publication date of the Swedish version: 2013-04-05

For enquiries contact The Swedish Information Centre for Rare Diseases, The Sahlgrenska Academy at the University of Gothenburg, Box 422, SE-405 30 Gothenburg, Sweden. Tel: +46 31 786 55 90, email: ovanligadiagnoser@gu.se.

 

About the database

This knowledge database provides information on rare diseases and conditions. The information is not intended to be a substitute for professional medical care, nor is it intended to be used as a basis for diagnosis or treatment.