How the Diagnosis is Made

The average length at birth is 49 cm, which is within the normal range. Pseudoachondroplasia is therefore not readily recognized at birth. But, lack of longitudinal growth manifests itself in the first 2 years of life (below 5^th percentile on standard growth charts). By this point the abnormal gait is present and measurements suggest pseudoachondroplasia. Diagnosis is typically made between 1 and 4 years of age and is based on clinical examination and characteristic x-ray appearances. Prenatal testing is now available by direct DNA analysis. The test detects the abnormal COMP gene by mutation scanning. Prenatal diagnosis may be appropriate during pregnancy in women with pseudoachondroplasia. It must be stressed that the majority of cases are spontaneous mutations.