Yet, re-evaluation of the clinical features of variant carriers in UK and Norway diabetes registries and the fact that it is present only in the longest HNF1A transcript isoform expressed predominantly in liver suggest that it is more likely to be a contributing factor to common multifactorial diabetes rather than a primary driver of early-onset sulfonylurea-responsive familial hyperglycemia. The gene discussed is HNF1A; the disease is diabetes mellitus.