Further evidence for the organisation of the four sarcoglycans proteins within the dystrophin-glycoprotein complex

Based on the pattern of distribution of the SG proteins in patients with LG MD2C and 2D, and on the observed decreased abundance of dystrophin through WE in some sarcoglycans (SG) patients, we have recently suggested that alph a, beta and delta subunits of sarcoglycan complex might be more closely ass ociated and that gamma-SG might interact more directly with dystrophin, Two additional SG patients here reported give further support to these suggest ions: an LGMD2F patient showed patchy labelling for gamma-SG, despite the l ack of staining of the other three SG proteins; an LGMD2C boy showed defici ency in dystrophin by means of WE and IF, comparable with an DMD manifestin g carrier. These two patients represent further evidence of a closer relati on of alpha, beta and delta-SG than of gamma-SG and of the possible associa tion of gamma-SG with dystrophin, In addition the LGMD2C patient illustrate s the potential risk of misdiagnosis using only dystrophin analysis, in cas es with no positive family history or when DNA analysis is not informative.