Total truncation of the molybdopterin/dimerization domains of SUOX protein in an Arab family with isolated sulfite oxidase deficiency

We ascertained a patient with the full-blown phenotype of isolated sulfite oxidase deficiency in a consanguineous Arab family. The proband's phenotype included the presence of intractable seizures in the neonatal period, some dysmorphic features, neuroradiologic findings reminiscent of hypoxic ischemic encephalopathy and rapidly progressive brain destruction leading to severe neurodevelopmental impairment. Biochemically, the patient excreted a large amount of S-sulfocysteine with normal amounts of xanthene and hypoxanthine and had normal plasma uric acid, which was consistent with isolated sulfite oxidase deficiency. We report the identification of the first Arab mutation in SUOX, the gene for sulfite oxidase enzyme, in the ascertained family. The newly identified Arab mutation in the SUOX gene (a single nucleotide deletion, del G1244) is predicted to cause a frame shift at amino acid 117 of the translated protein with the generation of a stop codon and total truncation of the molybdo-pterin- and the dimerizing-domain(s) of SUOX protein expressed from the mutant allele. The identification of this new Arab SUOX mutation should facilitate pre-implantation genetic diagnosis and selection of unaffected embryos for future pregnancy in the ascertained family with the mutation and related families with the same mutation.

Tuberculous anterior neck mass simulating goitre

A 13-year-old Saudi boy was referred to the paediatric endocrinology clinic for evaluation of rapidly progressive goitre with weight loss of 6 months duration. A clinical diagnosis of possible thyroid malignancy was made. On exploration the mass was found to be tuberculous in origin, attached to the thyroid gland, and responded to partial excision and anti-tuberculous chemotherapy. Tuberculosis should be considered in the differential diagnosis of anterior midline neck masses.