Hb Nancy and Hb Osler: two distinct genetic variants with identical clinical and hemoglobin phenotype.
Three hemoglobin variants (Hb Nancy, Osler and Fort Gordon), carrying the same Tyr-->Asp substitution at position beta 145 (HC2), have been independently described in 1975 in patients with marked polycythemia. The first one was found in a French caucasian family from Lorraine, and the two others in African Americans. Two unrelated individuals with Hb Osler have been recently reinvestigated at the DNA level and surprisingly, in their beta gene, codon 145 was found to be AAT which encodes for asparagine and not for aspartic acid, the aspartate at the protein level resulting, thus, from a very efficient posttranslational event. We reinvestigated a patient from the family of Hb Nancy and found that codon 145 was GAT, encoding for aspartate. This demonstrates that Hb Nancy is genetically distinct from Hb Osler despite an almost identical phenotype.
Service de biochimie et Inserm U468, hôpital Henri-Mondor, Créteil, France.
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Préhu
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Godart
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Vigneron
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Wajcman
D001216:Asparagine / Q000235:genetics; D001224:Aspartic Acid / Q000235:genetics; D001483:Base Sequence; D044383:Black People / Q000235:genetics; D003062:Codon; D005602:France; D005914:Globins / Q000235:genetics; D006455:Hemoglobins, Abnormal / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D010641:Phenotype; D016133:Polymerase Chain Reaction; D014443:Tyrosine / Q000235:genetics; D014481:United States; D044465:White People / Q000235:genetics; D001741:Black or African American
D003062:Codon; D006455:Hemoglobins, Abnormal; D001224:Aspartic Acid; D014443:Tyrosine; C036601:hemoglobin Osler; D001216:Asparagine; D005914:Globins