Contrary to what was observed for anti-SRP positive patients in whom IgG1 and IgG4 were principally observed while all four subclasses could possibly be found depending on the patient [16], or to other autoimmune diseases such as myasthenia gravis, membranous glomerulonephritis or pemphigus, in which both IgG1 and IgG4 isotypes have been found [24-26], the only subclass detected in anti-HMGCR positive patients was IgG1 in the present study. This evidence concerns the gene HMGCR and myasthenia gravis.