We previously evaluated the impact of several genes on abnormal glycosylation in galactosaemia patients and noted significant altered expression of a number of relevant N-glycan biosynthesis genes in peripheral blood mononuclear cells (PBMCs) from adult galactosaemia patients involving four key N-glycan biosynthesis genes: ALG9, MGAT3, FUT8 and B4GALT1 which correlated with the IgG variant profiles also identified in the study [9]. This evidence concerns the gene ALG9 and galactosemia.