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Achondroplasia is the most frequent form of chondrodysplasia with a prevalence of one child in every 15,000. This type of dwarfism is characterized by short limbs, hyperlordosis, short hands, and macrocephaly with high forehead and saddle nose. Size deficit is relatively important (adult size is approximately 130 cm +/- 10cm). Deformations of the skeleton are moderate and include hyperlordosis and genu varum. Neurological complications may appear due to a narrow vertebral canal. Mental development is normal. Diagnosis is based on radiological findings. The disorder is autosomal dominant, although about 90% of the affected patients are born to unaffected parents. These cases are due to new mutations, i.e. genetic `accidents` on the FGFR3 gene coding for a growth hormone fibroblastic receptor that is expressed in temporary cartilage. The mutation concerns only one gene, and can be detected by means of molecular analysis. Prenatal diagnosis is available. Up to now, orthopedic treatment is the only possible therapy.
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