Hypochondroplasia in a child with 1620C>G (Asn540Lys) mutation in FGFR3.

[achondroplasia]

Hypochondroplasia (HCP ) is an autosomal dominant skeletal dysplasia characterized by short extremities , short stature and lumbar lordosis , usually exhibiting a phenotype similar to but milder than achondroplasia (ACP ). Fibroblast growth factor receptor 3 gene (FGFR 3 ) mutations in the germline are well-known causes of skeletal syndromes . FGFR 3 is a negative regulator of bone growth and all mutations in FGFR 3 are gain-of-function mutations that lead to skeletal dysplasias . We report a child who presented with short stature , a relatively long trunk , short legs , short arm span , radiographic evidence of HCP and mild mental retardation . Genetic analysis revealed a heterozygous 1620 C >G (Asn 540 L ys ) mutation in FGFR 3 . To our knowledge , ours is the first case report of HCP with a heterozygous 1620 C >G (Asn 540 L ys ) mutation in Turkey .