Proponents of the theory that underlying alterations in FcRn are the cause for low IgG in DM1 have used mathematical modelling of kinetic analysis [9] to demonstrate that a normal number of FcRn with lowered affinity for IgG but normal affinity for albumin may explain why most patients with DM1 have low concentration of serum IgG and normal serum albumin [4], as was shown in both of our cases. This evidence concerns the gene ALB and myotonic dystrophy type 1.