A rare cause of mental motor retardation: recessive congenital methemoglobinemia type II

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 deficien...

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Bibliographic Details
Main Authors: Deniz Yüksel, Nesrin Senbil, Deniz Yilmaz, Neşe Yarali, Y K Yavuz Gürer
Format: Article
Language:English
Published: Hacettepe University Institute of Child Health 2009-04-01
Series:The Turkish Journal of Pediatrics
Online Access:https://turkjpediatr.org/article/view/2285
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Summary: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.
ISSN:0041-4301
2791-6421