A splice-site mutation leads to haploinsufficiency of EXT2 mRNA for a dominant trait in a large family with multiple osteochondromas.

Multiple osteochondromas (MO) is an autosomal-dominant disorder and mutations in EXT1 and EXT2 account up to 78% of the cases studied, including missense, nonsense, frameshift, and splice-site mutations. EXT1 and EXT2 encode glycosyltransferases required for the synthesis of heparan sulfate (HS) chains. The molecular pathogenesis underlying these mutations is still largely unknown.

A study on the structural properties of the lumbar endplate: histological structure, the effect of bone density, and spinal level.

Study Design: Histologic experiments and biomechanical tests were performed in human cadaveric lumbar spine models.

Objective: To determine (1) the anatomic structures of lumbar endplates, (2) the relationship between bone mineral density (BMD) and biomechanical properties of lumbar endplates, and (3) the influence of spinal level on the failure loads of lumbar endplates.

Summary Of Background Data: Previous works have shown that the posterolateral corners of the lumbar endplates are stronger than the anterior and central regions.