Probing the Chondrodystrophies:
University of Chicago Medical Center researcher Charles M. Strom, MD, PhD, has found that at least one third of a type II collagen gene is missing in a 14-month-old girl with achondroplasia, a common form of dwarfism (JAMA [MEDICAL NEWS] 1983; 250:323-330).The gene is relatively large, so it isn't certain that this particular defect occurs in all cases. Still, Strom believes that it is likely to be found in most patients with achondroplasia, which presently is unpreventable and can be treated only with surgery.Type II is the major structural protein of cartilage, where the only apparent physiological defect in patients with achondroplasia has been noted. Strom and William B. Uphold, PhD, isolated the chick gene for this protein (which essentially is inaccessible in humans), cloned it through recombinant-DNA methods, then used it as a probe to purify the analogous human gene from a recombinant-DNA library.