PRENATAL-DIAGNOSIS OF OSTEOGENESIS IMPERFECTA TYPE-II

Objective: To characterize the prenatal sonographic features of osteog enesis imperfecta (OI) type II. Design: Descriptive (case series). Set ting: Department of Obstetrics and Gynecology, Faculty of Medicine, Ma haraj Nakorn Chiang Mai Hospital, Chiang Mai University. Subjects: Six fetuses with prenatal diagnosis of OI were evaluated. Results: Six fe tuses were prenatally diagnosed as OI type TT in five mothers without familial history of the disease. One mother had two consecutive pregna ncies complicated with this condition. The first five cases were class ified as OI type IIA, while the last one was OI type IIB. All of subty pe A exhibited typical triad of bone shortening, diffuse hypomineraliz ation and multiple fractures of long bones including beaded ribs where as the subtype B showed shortening of only femurs, normal bone echoden sity and isolated fractures of long bones. The postnatal radiography a nd autopsy confirmed the prenatal diagnosis in all cases. Other findin gs may occasionally be found, including polyhydramnios, oligohydramnio s, hydrop fetalis and small for gestational age. Conclusion: The triad of bone shortening, decreased bone density and numerous fractures inc luding beaded ribs permits a confident diagnosis of OI type IIA. Furth ermore, sonographic features may differentiate the subtype of OI type II, depending on degree of bone shortening and echodensity. (C) 1998 I nternational Federation of Gynecology and Obstetrics.