IARS2 and infantile spasms: Both siblings had novel, compound heterozygous IARS2 [(c.680 T > C; p.[(Phe227Ser)] and c.2450G > A; p. [(Arg817His)] variants in exons 4 and 20, respectively, and exhibited delayed motor development, as well as infantile spasms and abnormal brain MRI diagnostic imaging leading to a diagnosis of Leigh syndrome.