Lenherr-Taube N, Young EJ, Furman M, et al. - In this cross-sectional study, researchers sought to describe the genetic associations and biochemical profile of mild idiopathic infantile hypercalcemia (IIH), an uncommon disorder characterized by elevated serum concentrations of 1,25(OH)2D and low PTH levels. Children with IIH between the ages of 6 months and 17 years old were followed in the Calcium Clinic at the Hospital for Sick Children (SickKids) in Toronto, Canada. Twenty children with mild IIH on calcium-restricted diets were assessed. The milder form of IIH has a distinctive vitamin D metabolite profile and is associated primarily with heterozygous SLC34A1 and SLC34A3 variants.