SLC2A2 and glycogen storage disease due to GLUT2 deficiency: Regarding the OB population, it is known that the Fleckvieh haplotype 2 (FH2) and the associated frameshift variant in the SLC2A2 gene segregate in the OB population at an allele frequency of 0.05 and cause the Fanconi-Bickel syndrome with growth retardation [9, 72].