G6PC1 and Hypoglycemia: The G6PC p.P257L variant had approximately 1.2%–6.4% of the G6Pase activity relative to the WT human G6PC in cell-based assays (23, 39) and is known as a variant associated with mild symptoms: a carrier homozygous for the variant had never experienced symptomatic hypoglycemia without any dietary management (23).