Molybdenum cofactor deficiency is a rare human disease in which the absence of molybdenum cofactor leads to accumulation of toxic levels of sulphite and neurological damage. Usually this leads to death within months of birth, due to the lack of active sulfite oxidase. Furthermore, a mutational block in molybdenum cofactor biosynthesis causes absence of enzyme activity of xanthine dehydrogenase/oxidase and aldehyde oxidase.

Molybdenum cofactor deficiency
Other namesSulfite oxidase deficiency due to molybdenum cofactor deficiency
SpecialtyMedical genetics



When caused by a mutation in the MOCS1 gene it is the type A variant. It can also be caused by a mutation in the MOCS2 gene or the GEPH gene.[1] As of 2010, there had been approximately 132 reported cases.[2]

It should not be confused with molybdenum deficiency.


Diagnosis of Molybdenum cofactor deficiency includes early seizures, low blood levels of uric acid, and high levels of sulphite, xanthine, and uric acid in urine. Additionally, the disease produces characteristic MRI images that can aid in diagnosis.[3]



The prevalence of Molybdenum co-factor deficiency is estimated as being between 1 in 100 000 and 1 in 200 000. To date more than 100 cases have been reported. However, this may significantly under represent cases.


In 2009, Monash Children's Hospital at Southern Health in Melbourne, Australia reported that a patient known as Baby Z became the first person to be successfully treated for molybdenum cofactor deficiency type A. The patient was treated with cPMP, a precursor of the molybdenum cofactor.[4][5] Baby Z will require daily injections of cyclic pyranopterin monophosphate (cPMP) for the rest of her life.[6]

See alsoEdit


  1. ^ Reiss J, Johnson JL (June 2003). "Mutations in the molybdenum cofactor biosynthetic genes MOCS1, MOCS2, and GEPH". Human Mutation. 21 (6): 569–76. doi:10.1002/humu.10223. PMID 12754701.
  2. ^ Ichida K, Aydin HI, Hosoyamada M, et al. (2006). "A Turkish case with molybdenum cofactor deficiency". Nucleosides, Nucleotides & Nucleic Acids. 25 (9–11): 1087–91. doi:10.1080/15257770600894022. PMID 17065069.
  3. ^ "Archived copy". Archived from the original on 2008-10-11. Retrieved 2009-11-08.CS1 maint: Archived copy as title (link)[full citation needed]
  4. ^ McArthur, Grant (November 5, 2009). "Doctor cures 'Baby Z' of molybdenum cofactor deficiency in medical world first". Retrieved November 5, 2009.
  5. ^ Samantha Donovan (2009-11-05). "Dying baby cured in world first". Australian Broadcasting Corporation. Retrieved 2009-11-05.
  6. ^ Tedmanson, Sophie (November 5, 2009). "Doctors risk untried drug to stop babys brain dissolving". The Times. London. Retrieved May 13, 2010.

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