ABNORMAL EXPRESSION OF LAMININ SUGGESTS DISTURBANCE OF SARCOLEMMA EXTRACELLULAR-MATRIX INTERACTION IN JAPANESE PATIENTS WITH AUTOSOMAL RECESSIVE MUSCULAR-DYSTROPHY DEFICIENT IN ADHALIN

Dystrophin is associated with several novel sarcolemmal proteins, incl uding a laminin-binding extracellular glycoprotein of 156 kD (alpha-dy stroglycan) and a transmembrane glycoprotein of 50 kD (adhalin). Defic iency of adhalin characterizes a severe autosomal recessive muscular d ystrophy prevalent in Arabs. Here we report for the first time two mon goloid (Japanese) patients with autosomal recessive muscular dystrophy deficient in adhalin. Interestingly, adhalin was not completely absen t and was faintly detectable in a patchy distribution along the sarcol emma in our patients. Although the M and B2 subunits of laminin were p reserved, the B1 subunit was greatly reduced in the basal lamina surro unding muscle fibers. Our results raise a possibility that the deficie ncy of adhalin may be associated with the disturbance of sarcolemma-ex tracellular matrix interaction leading to sarcolemmal instability.