Schneckenbecken dysplasia

Signs and symptoms

Fetuses typically exhibit a hypoplastic iliac bone resembling a snail, short ribs, short neck, and dysplastic fibulae. Long bones are shortened and broadened like dumbbells, with premature tarsal ossification, vertebral flattening, macrocephaly, dolichocephaly, toenail hypoplasia, flattened malar prominence, and micromelic dwarfism. Affected homozygotes usually die before birth and do not experience disease complications.

Mouse knockout model

In 2007, Hiraoka et al. created an SLC35D1-knockout mouse model. Heterozygous mice were born normally, but homozygous mice died in neonatal life. These mice had micromelia, craniofacial bone hypoplasia, vertebral flattening, and severely short long and iliac bones. Hiraoka noted these symptoms resembled human Schneckenbecken dysplasia and concluded the gene is important for normal prenatal skeletal formation in mice.

Did You Know?

• The condition is named after the German translation for 'snail-pelvis' (Schneckenbecken).
• The name was first used by Borochowitz et al. when describing a Californian fetus.
• The couple who had the first described cases experienced 13 pregnancies: 4 healthy children, 5 dead dwarf babies, 3 miscarriages, and 1 clinical abortion after prenatal detection of dwarfism.