How common is achondroplasia?
Achondroplasia is the most common skeletal dysplasia. Although the exact incidence is not known estimates range from 1 in 15,000 to 1 in 26,000 births (1,2). Is achondroplasia inherited? Achondroplasia is inherited in an autosomal dominant manner, but about 75% of patients with achondroplasia represent new mutations. These new mutations are typically arise from the father during sperm formation. Paternal age greater than 35 years has been found to be a risk factor (3,4). What causes achondroplasia? Achondroplasia is caused by a mutation in the fibroblast growth factor receptor-3 (FGFR-3) gene (3). Mutations which change the amino acid glycine to arginine at position 380 of the FGFR-3 protein account for >97% of all reported cases of achondroplasia. Normally the FGFR-3 protein functions as “brake” for endochondral bone growth. This typical G380R mutation actually increases the ability of the FGFR-3 protein to slow bone growth and causes the features of achondroplasia. This type of chang
