Czech dysplasia occurring in a Japanese family.

Czech dysplasia (OMIM 609162) is a recently established COL2A1 disorder characterized by normal height, early-onset osteoarthritis, platyspondyly, short metatarsals, and the absence of ophthalmological complications or cleft palate. A specific missense mutation (c.823C > T, R275C) in the exon 13 of the COL2A1 gene, coding for the triple helical domain of the alpha 1 chain of the type II collagen, has been linked to Czech dysplasia, which is quite a unique situation among the COL2A1 disorders. Since all of the 11 families and patients reported to date were of European ancestry, an ancient single origin of the R275C mutation was speculated about. Here we report on a Japanese family consisting of three patients with Czech dysplasia, each member showing valgus knees in addition to remarkably uniform manifestation of the clinical and radiological abnormalities. Mutation analysis documented the COL2A1 c.823C > T mutation in all affected individuals. In conclusion, this report provides novel evidence for the independent occurrence of Czech dysplasia among the populations.