A novel mutation in type II methemoglobinemia

J Child Neurol. 2010 Jan;25(1):91-3. doi: 10.1177/0883073809336136. Epub 2009 May 26.


Type II methemoglobinemia is a somatic deficiency of cytochrome b5 reductase with severe global neurologic impairment. We report a novel mutation in exon 3 of the CYB5R3 gene on chromosome 22 consisting of homozygous 1-base pair (bp) deletion noted as c.215delG; p.Gly72AlafsX100. The patient had improvement of gross motor skills, chewing, and swallowing that may be due to the initiation of daily ascorbic acid therapy. We hypothesize that a possible response to ascorbic acid may be related to the effect of making additional ferrous iron available for its role as a cofactor in carnitine synthesis.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Ascorbic Acid / therapeutic use
  • Child
  • Cytochrome-B(5) Reductase / genetics*
  • Dyskinesias / drug therapy
  • Dyskinesias / etiology
  • Dyskinesias / genetics
  • Female
  • Honduras
  • Humans
  • Male
  • Methemoglobinemia / complications
  • Methemoglobinemia / drug therapy
  • Methemoglobinemia / genetics*
  • Mothers
  • Sequence Analysis, DNA
  • Sequence Deletion*
  • Treatment Outcome
  • Vitamins / therapeutic use


  • Vitamins
  • Cytochrome-B(5) Reductase
  • Ascorbic Acid