allopurinol and Metal-Metabolism--Inborn-Errors

In a 3-week old female child with clinical features including neurologic abnormalities and lens dislocation, xanthinuria co-existed with increased excretion of sulfur compounds (sulfite, S-sulfocysteine, taurine and thio-sulfate). Low xanthine oxidase and absent sulfite oxidase activities were found on liver biopsy. No abnormality was detected in either parent. Both the above enzymes are molybdenum-flavoproteins. Normal serum molybdenum concentration seemed to rule out dietary deficiency or impaired absorption. A defect in the incorporation of the metal into flavoproteins is postulated in this case.

Topics: Animals; Cattle; Humans; Intestines; Kinetics; Liver; Metal Metabolism, Inborn Errors; Molybdenum; Oxidoreductases; Oxidoreductases Acting on Sulfur Group Donors; Rats; Xanthine Oxidase

A child is described who presented in the neonatal period with feeding difficulties, severe neurological abnormalities, lens dislocation of the eyes and dysmorphic symptoms of the head. Routine laboratory investigations revealed a decreased serum urate and a positive sulphite reaction of the urine. Subsequent chromatographic examinations showed xanthinuria and increased excretion of S-sulphocysteine and taurine to be present. In addition, high thiosulphate and low sulphate excretions in the urine were observed. Xanthine oxidase deficiency was demonstrated in a jejunal biopsy specimen, whereas the excretion of sulphur containing substances was considered to be characteristic of sulphite oxidase deficiency. This new combination of defects may be the result of malfunctioning of both enzymes, possibly caused by alterations in the essential molybdenum containing active centre of the enzymes, which they share in common.

Topics: Abnormalities, Multiple; Biological Transport; Cysteine; Female; Humans; Infant, Newborn; Metal Metabolism, Inborn Errors; Molybdenum; Oxidoreductases; Oxidoreductases Acting on Sulfur Group Donors; Xanthine Oxidase