title: A novel mutation in type II methemoglobinemia.
abstract: 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.
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology/Oncology, Medical University of South Carolina, Charleston, South Carolina, USA. Hudspeth@musc.edu
authors.forename: Michelle P
authors.initials: MP
authors.lastname: Hudspeth
authors.forename: Sumy
authors.initials: S
authors.lastname: Joseph
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Holden
mesh_terms: D000328:Adult; D001205:Ascorbic Acid / Q000627:therapeutic use; D002648:Child; D042966:Cytochrome-B(5) Reductase / Q000235:genetics*; D020820:Dyskinesias / Q000188:drug therapy / Q000209:etiology / Q000235:genetics; D005260:Female; D006721:Honduras; D006801:Humans; D008297:Male; D008708:Methemoglobinemia / Q000150:complications / Q000188:drug therapy / Q000235:genetics*; D009035:Mothers; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D016896:Treatment Outcome; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D014815:Vitamins; D042966:Cytochrome-B(5) Reductase; D001205:Ascorbic Acid