Molybdenum cofactor deficiency

Molybdenum cofactor deficiency is a rare human disease in which the body lacks molybdopterin and therefore its molybdenum complex, the molybdenum cofactor. The result is a build-up of toxic sulphite and neurological damage, and the disease usually leads to death within months of birth because active sulfite oxidase is missing. The same block also removes the activity of xanthine dehydrogenase or oxidase and of aldehyde oxidase. The type A variant is caused by a mutation in the MOCS1 gene, and mutations in MOCS2 or GPHN can also cause it. Diagnosis rests on early seizures, low blood uric acid, high sulphite, xanthine and uric acid in urine, and characteristic MRI findings, and affected infants may show abnormal muscle tone, feeding difficulty, microcephaly, coarse facial features and lens dislocation. Prevalence is estimated between one in 100,000 and one in 200,000. In 2021 the US Food and Drug Administration approved fosdenopterin for type A, and in 2009 an Australian infant known as Baby Z was the first person successfully treated with the precursor cPMP. The atlas gives no medical advice.