An Overview of Epidemiology and Genetics

Abstract

Ossification of the posterior longitudinal ligament of the spine (OPLL) can cause not only spinal rigidity but also severe paralysis due to compression of the spinal cord by an ectopic ossification of the posterior longitudinal ligament. The prevalence of cervical OPLL is 1.9-6.3% in the Japanese, 0.95-3.6% in other Southeast Asians, and 0.01-1.7% in North American and Europeans. OPLL is ordinarily diagnosed after the age of 50 years. While OPLL can be a secondary complication in patients with monogenic diseases, most clinical cases of OPLL are idiopathic. Idiopathic OPLL is considered to be a multifactorial disease with both genetic and environmental factors contributing to its development and progression. Age, diabetes mellitus, obesity, and mechanical stress have been proposed as clinical and environmental risk factors. On the other hand, OPLL is known to have a strong genetic predisposition. Recently, several genetic studies have demonstrated several genes/loci that link to OPLL susceptibility, but, to date, none of the genes has yet been proven as a functionary gene responsible for the development of OPLL. This chapter reviews the recent progress in the epidemiologic and genomic studies of OPLL.