Genetic factors play a major role in the expression
of OA; however, the influence of heredity varies in
different joints.9 Susceptibility to OA has been investigated
by genome-wide linkage of families with OA
and candidate gene association studies in unrelated
individuals.9 No specific genes for predicting OA have
been identified yet, but those that regulate the synthesis
of the various components of cartilage rather
than coding for specific structural proteins offer the
greatest promise. Current evidence suggests that the
influence of heredity on OA development is greater
in women than in men—as high as 60% for hand
and hip OA, but considerably lower for knee OA
(estimates range from 10% to 39%).9 In several epidemiologic
studies, the influence of inheritance in