However, other data do not support the proposal that alterations in FcRn results in low IgG in DM1, including human studies where FcRn transcript number was not lower in muscle biopsies or peripheral blood lymphocytes in patients with DM1, and the FcRn transcript number did not correlate with CTG repeat number or serum IgG level [6]. This evidence concerns the gene FCGRT and myotonic dystrophy type 1.