Case of mild Schmid-type metaphyseal chondrodysplasia with novel sequence variation involving an unusual mutational site of the COL10A1 gene.

Schmid-type metaphyseal chondrodysplasia (MCDS) is characterized by short stature with short legs, bowing of the long bones, coxa vara, and waddling gait. MCDS is a relatively common form of MCD. Most mutations that cause MCDS occur within the carboxyl-terminal non-collagenous domain (NC1) of the COL10A1 gene. We performed mutational analysis of the COL10A1 genes in 4 unrelated Korean patients with diagnosed MCDS. Mutational analysis of COL10A1 identified c.1904_1915delinsT (p.Gln635LeufsX10) and c.1969dupG (p.Ala657GlyfsX10), 2 novel frameshift mutations, and c.2030T>A (p.Val677Glu) and c.862G>C (p.Gly288Arg) at unusual mutational sites, which could be pathogenic. We present the first report of the molecular characteristics of MCDS in 4 Korean patients. Our findings suggest that a novel sequence variation involving an unusual mutational site of the COL10A1 gene can cause mild MCDS.