Here, we describe a pediatric HOMG1 case with novel compound heterozygous mutations of <i>TRPM6</i> (c.1483 C > T [p.Gln495*] and c.2715del [p.Trp905*]) in a 2-month-old boy who developed refractory seizures due to hypomagnesemia with secondary hypocalcemia. The gene discussed is TRPM6; the disease is Hypomagnesemia.