SLC2A1 and hyperinsulinemic hypoglycemia, familial, 4: Targeted analysis of SLC2A1 identified one known variant and two potentially disease-causing variants: the c.929C>T (p.Thr310Ile) mutation found in case 189 has previously been reported to cause GLUT1 deficiency [33]; a SLC2A1 c.203C>T (p.Ser68Leu) variant was found in patient 109, which is absent from gnomAD, but reported in ClinVar as a VUS for GLUT1 deficiency; and an intronic variant (c.972+7del; p.Leu232PhefsTer)?