Schneckenbecken dysplasia, radiology, and histology

Abstract

To our knowledge this is the first report of Schneckenbecken dysplasia with the development of hydrops early in the second trimester. The radiological findings showed the typical hypoplastic iliac bones with medial extension and very flattened, on lateral view, oval-shaped vertebral bodies and short long bones. The histology showed hypercellular and hypervascular cartilage with chondrocytes with centrally located nucleus. The absence of the lacunar space as described before was also observed in some chondrocytes in our case. This male fetus was the product of consanguineous parents of Mediterranean origin compatible with autosomal recessive inheritance.

Schneckenbecken Dysplasia in Fetus: Report of Four Cases

“…Grossly, besides signs described in our cases such as macrocrania, a narrow chest, a dilated abdomen and especially short and dumbbell-like limbs, deformities of the skull, rump and extremities as well as hypoplastic lungs were also reported [1,3,4] . Nikkels et al [5] describe a hydrops as we found in our second reported case.…”

“…Vascular penetration is increased, and the columns of proliferating cartilage are short and irregular [1,3,4] . Absence of a lacunar space around the chondrocytes, described first by Borochowitz et al [1] , was also reported by other authors [5] . This histological feature could be caused by an abnormal formation of the chondroid matrix, as was observed in another group of skeletal dysplasias with a mutation in a sulfate transporter protein [5] .…”

“…Absence of a lacunar space around the chondrocytes, described first by Borochowitz et al [1] , was also reported by other authors [5] . This histological feature could be caused by an abnormal formation of the chondroid matrix, as was observed in another group of skeletal dysplasias with a mutation in a sulfate transporter protein [5] . Ultrastructural features are nonspecific; however, cell membranes of most chondrocytes are immediately adjacent to the interterritorial matrix leaving no lacunar space.…”

“…Histological findings of SD seem to be specific and differ from those observed in achondrogenesis type IB (intracytoplasmic periodic acid-Schiffpositive inclusions), achondrogenesis type II (larger chondrocytes with clear cytoplasm), fibrochondrogenesis (fibrous cartilage matrix) or thanatophoric dysplasia (disruption of the epiphyseal plate by foci of membranous ossification) [3] . SD should also be mentioned in the differential diagnosis of platyspondylic lethal chondrodysplasia, especially the Torrance and San Diego type, and some types of the short-rib (polydactyly) syndromes [5,7] .…”

Identification of loss-of-function mutations of SLC35D1 in patients with Schneckenbecken dysplasia, but not with other severe spondylodysplastic dysplasias group diseases

“…Schneckenbecken dysplasia (SBD; OMIM 269250) is an autosomal recessive perinatally lethal skeletal dysplasia 1 – 3. The German term “Schneckenbecken” refers to the distinctive, snail-like appearance of the ilia due to medial bone projection from the inner iliac margin.…”