Other population-specific alleles not imputed in the current study, such as *2 that is almost restricted to Caucasians, or *6 (rs75543815) and *8 (rs56161402) that occur at frequencies between 1.5 and 3.5% in some African and Asian populations (Oliveira et al., 2007), are also important contributors of TPMT deficiency. The gene discussed is TPMT; the disease is hyperinsulinemic hypoglycemia, familial, 4.