Novel missense mutation resulting in the substitution of tyrosine by cysteine at codon 597 of the type X collagen gene associated with Schmid metaphyseal chondrodysplasia

Schmid metaphyseal chondrodysplasia (SMCD) is one of the most common forms of the osteochondrodysplasias. Mutations or deletions in the COL10A1 gene t hat encodes type X collagen have been shown to cause this disorder. Most of the gene mutations and deletions are located in the non-collagenous carbox y (C)-terminal (NC1) domain. We describe a novel missense mutation in a pat ient with SMCD that leads to the substitution of Tyr at codon 597 by Cys in the NC1 domain. Sequence analysis indicated that the proband was heterozyg ous for the mutation. Her parents were homozygous for the normal sequence, indicating the de-novo occurrence of this mutation.