Case report 693: Schneckenbecken dysplasia.

Three siblings with SBD from consangineous parents are reported. The prenatal diagnosis of a short-limbed form of dwarfism was made by ultrasonography and the final diagnosis in the index case by radiography, demonstrating a short-limbed, platyspondylic dwarf with a snail-like configuration of the ilium and vertebral bodies, flat on AP and round on lateral view. The histological examination showed a generalized, severe disturbance of cartilage formation with marked hypercellularity of proliferating and resting zones, reduction of intercellular matrix, and shortening of the irregular columns of proliferating cartilage. The ultramicroscopic findings were nonspecific. This is the first report of SBD after the original description, bringing the total to 14 cases in 5 families. The correct radiological diagnosis and the differential diagnosis, in particular thanatophoric dysplasia, are essential for genetic counselling and obstetrical guidance of families affected with this autosomal recessive dysplasia.