Usefulness of fetal autopsy in the diagnosis of blomstrand chondrodysplasia: a report of three cases.

Blomstrand osteochondrodysplasia (BOCD) is a rare autosomal recessive sclerosing skeletal dysplasia characterized by accelerated chondrocyte differentiation. In this article, we discuss three cases where lethal skeletal dysplasia was suspected and Blomstrand dysplasia was diagnosed by autopsy. Antenatal ultrasound findings include increased nuchal translucency, tetramicromelia and polyhydramnios. Radiological hallmark is advanced skeletal maturation and bone sclerosis. Histology of long bones revealed narrow cartilagenous cap and changes in the physeal growth zone which showed severe hypoplasia and disorganization of proliferative phase and hypertrophic phase. Homozygous and compound heterozygous mutations in PTHR1 gene have been implicated in the pathogenesis of this chondrodysplasia.