title: A rare cause of mental motor retardation: recessive congenital methemoglobinemia type II.
abstract: Recessive congenital methemoglobinemia (RCM) is a very rare disorder caused by NADH- cytochrome b5 reductase (cytb5r) deficiency. It has been classified into four types. Type I presents with mild cyanosis due to a significant deficiency of cytb5r in erythrocytes only. In type II, the deficiency occurs in all tissues and causes growth and mental retardation and other neurological impairments. RCM types I and II are caused by a defect in a single gene, which is located on chromosome 22 (locus DIA 1: q 13.31-qter). Prenatal diagnosis is possible. Cyanosis can be well treated by 200-500 mg of ascorbic acid daily; there is no effective therapy for the progressive neurological impairments. This report presents two siblings with central cyanosis, growth retardation, mental retardation, microcephaly, dystonia and hypertonia diagnosed as RCM type II.
authors.affiliation: Dr. Sami Ulus Child Health and Diseases Training and Research Hospital, Ankara, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Yüksel
authors.forename: Nesrin
authors.initials: N
authors.lastname: Senbil
authors.forename: Deniz
authors.initials: D
authors.lastname: Yilmaz
authors.forename: Neşe
authors.initials: N
authors.lastname: Yarali
authors.forename: Y K Yavuz
authors.initials: YK
authors.lastname: Gürer
mesh_terms: D001205:Ascorbic Acid / Q000627:therapeutic use; D002675:Child, Preschool; D003241:Consanguinity; D005808:Genes, Recessive; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D008279:Magnetic Resonance Imaging; D008297:Male; D008708:Methemoglobinemia / Q000151:congenital* / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D035781:Siblings; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D014815:Vitamins; D001205:Ascorbic Acid