However, the identification of insertion mutants (vtc2-4 and vtc2-5) in VTC2 which have similarly low ascorbate but are only slightly smaller, along with finding that backcrossing vtc2-1 to the wild type segregated small size from ascorbate deficiency (Lim et al., 2016), confirms that severely decreased growth in this mutant is not linked to ascorbate deficiency. This evidence concerns the gene GDPGP1 and hyperinsulinemic hypoglycemia, familial, 4.