TYPE-II COLLAGENOPATHIES - ARE THERE ADDITIONAL FAMILY MEMBERS

The type II collagenopathies represent a group of chondrodysplasias sh aring clinical and radiological manifestations which are expressed as a continuous spectrum of phenotypes, ranging from perinatally lethal t o very mild conditions. Their common molecular bases are mutations in the type II collagen gene (COL2A1). We describe one case of lethal pla tyspondylic dysplasia, Torrance type, and a variant of lethal Kniest d ysplasia, neither of which has been reported as a type II collagenopat hy. Biochemical studies of cartilage collagens and morphological analy sis of cartilage sections suggest that abnormalities of type II collag en structure and biosynthesis are the main pathogenetic factors in bot h cases. Thus, the phenotypic spectrum of type II collagenopathies mig ht be greater than hitherto suspected. (C) 1996 Wiley-Liss, Inc.