We report an isolated sulfite oxidase deficiency in the first child boy of a non-consanguineous Caucasian family. He's a compound heterozygote for the sulfite oxidase gene, presenting low cystine, undetectable homocysteine and normal uric acid blood concentrations and undetectable sulfite oxidase activity in his cultured fibroblasts. Both mutations are not reported yet. The clinical presentation was typical and severe, with generalized status epilepticus and premature death.
Keywords: Compound heterozygote; Fibroblasts; Missense mutation; Point mutation; SUOX, sulfite oxidase; Sulfite oxidase activity; Transition; Transversion.