Humans with point mutations in the catalytic domain of Mgat2, which encodes GnTII, have a congenital disorder of glycosylation type IIa, a syndrome characterized by a general failure to thrive, dysmorphic facial features, feeding difficulties, and psychomotor retardation (Jaeken et al., 1993, 1994; Tan et al., 1996). This evidence concerns the gene MGAT2 and Failure to thrive.