MUSCULAR-DYSTROPHY ASSOCIATED WITH BETA-DYSTROGLYCAN DEFICIENCY

beta-Dystroglycan, a 43-kd transmembrane dystrophin-associated glycopr otein, plays an important role in linking dystrophin to the laminin-bi nding alpha-dystroglycan. alpha-/beta-Dystroglycan is encoded by a sin gle gene on chromosome 3p21 and ubiquitously expressed in muscle and n onmuscle tissues. No known human diseases have been mapped to this loc us. Here, we describe the selective deficiency of beta-dystroglycan in a 4-year-old Saudi boy with muscular dystrophy. The patient had a bor derline elevation of serum creatine kinase level and early-onset proxi mal symmetrical muscle weakness and wasting without calf hypertrophy. The milder phenotype may suggest a secondary deficiency of beta-dystro glycan; however, the unique immunofluorescence labeling suggests that the patient may present a novel form of muscular dystrophy.