SLC52A2 and Epileptic encephalopathy: Among these variants were c.1016 T > C (p.Leu339Pro) (RefSeq NM_001363118.2) in SLC52A2 (MAF = 0.60%), that has caused AR Brown-Vialetto van Laere syndrome type 2 in at least four genotypically confirmed homozygous carriers in Iceland2, c.655 G > A (p.Gly219Arg) (RefSeq NM_177550.4) in SLC13A5 (MAF = 0.49%), that has caused epileptic encephalopathy in at least three homozygous carriers in Iceland, and c.557 A > C (p.Glu186Ala) (RefSeq NM_000404.3) in GLB1 (MAF = 0.52%), that has caused GM1-gangliosidosis in at least one homozygous carrier in Iceland.