Etiology of Spine Deformity: Progress Update

PURPOSE: To demonstrate status of research on etiology and encourage further work.

IDIOPATHIC SCOLIOSIS-GENETICS: Linkage scans in families identified regions of the genome potentially encoding genes for Idiopathic Scoliosis (IS). Candidate loci are on chromosomes 10q, 6q, 15q, 18q, and Xq. . Study of pinealectomy showed that cutting the pineal stalk is the critical step producing scoliosis. However, pinealectomy does not produce scoliosis in all chickens, even though melatonin levels decline. A mouse model for kyphoscoliosis was identified, with mutation in a muscle-specific protein.

GROWTH DIFFERENCES: Some patients with IS have decreased bone density, osteocyte count, trabecular thickness and bone turnover. Scoliotic specimens showed that the length of the canal was short compared to the vertebral column. A mechanical model of scoliosis was produced by tether of the spinal cord.

CALMODULIN: Study of 55 immature patients with IS demonstrated that platelet calmodulin correlated with curve progression. It was elevated in all with progressive curves and stable in 75% of nonprogressive curves.

CONGENITAL DEFORMITY: defects in the notch signaling pathway have been found.

SCHEUERMANN KYPHOSIS: An autosomal dominant mode of inheritance has been confirmed. Bone mineral density was significantly decreased.