Combined xanthine and sulphite oxidase defect due to a deficiency of molybdenum cofactor

Molybdenum cofactor deficiency

We describe a new case of molybdenum cofactor deficiency, an underrecognized inborn error of metabolism that results in neonatal seizures and neurologic abnormalities. Characteristic biochemical defects in affected individuals include hypouricemia, elevated urine sulfate (detectable by dipstick), and elevated S-sulfocysteine (detectable by anion exchange chromatography). This disorder should be considered in the differential diagnosis of neonatal seizures.

Biochemical investigation of a child with molybdenum cofactor deficiency

A girl aged eight months, who presented with developmental delay and dislocated optic lenses, was diagnosed as having combined sulfite oxidase and xanthine dehydrogenase deficiencies consistent with molybdenum cofactor deficiency. The diagnosis was confirmed by demonstrating the absence in urine of urothione, a molybdenum cofactor metabolite. Prenatal diagnosis excluded the disease in the mother's second pregnancy. A summary of an in vitro study of molybdenum cofactor synthesis in the patient is given.

Molybdenum co-factor deficiency: an easily missed inborn error of metabolism

A female patient is described with combined deficiency of sulphite, zanthine and aldehyde oxidase. She presented at the age of four weeks with intractable seizures. Initially the diagnosis was suspected because of a very low serum urate level (23 mumol/1-1). This condition can be easily missed and it is proposed that measurement of serum urate be included in the metabolic assessment of neonates with unexplained seizures and developmental delay.

Analysis and clinical significance of pterins

This review briefly describes the biochemistry of pterins, their involvement in pathological processes and the use of pterin measurement in diagnosis and monitoring of disease. Chromatographic and other methods of pterin analysis are detailed with particular emphasis being placed on the need for correct sample collection and handling.