Important progress in the understanding of various aspects of dystrophin biology continued during the past year. This relates to basic biochemistry, isoforms, subcellular localization in skeletal muscle, regional distribution in brain, physiological role, abnormalities caused by gene mutations and nuclear domain characteristics. Major progress has also taken place in the characterization of the dystrophin-associated glycoprotein (DAG) complex and in the understanding of its role in anchoring dystrophin to the plasmalemma and providing a link to the extracellular matrix. Characterization of the human chromosome-6-related analogue of dystrophin led to the discovery that in Duchenne muscular dystrophy (DMD) this molecule is expressed diffusely at the muscle cell surface and could, in part, compensate for the dystrophin deficiency of DMD.