title: Haemoglobin O Padova and falsely low haemoglobin A1c in a patient with type I diabetes.
abstract: Glycated haemoglobin (HbA1c) measured by high performance liquid chromatography (HPLC) in a 20 year old female with insulin dependent diabetes mellitus was consistently within the normal range although her daily blood glucose values were > 11.1 mmol/l. HbA1c measured by immunoagglutination and fructosamine was elevated and correlated with the patient's blood glucose values. The HPLC chromatogram showed an additional peak at HbA0. Electrophoresis of haemoglobin on citrate agar gel revealed an abnormal haemoglobin anodal of HbS. Cellulose acetate electrophoresis and isoelectric focusing demonstrated an additional haemoglobin migrating close to HbA2. Amino acid analysis and DNA sequencing revealed an alpha 30 (B11) Glu-->Lys replacement, that is, haemoglobin O Padova. Investigations of two family members without diabetes revealed the same rare haemoglobin variant. This case showed that this silent haemoglobin mutation caused an additional peak and falsely low HbA1c values when measured by HPLC, the gold standard for this evaluation.
authors.affiliation: Department of Internal Medicine, Karl Franzens, University, Graz, Austria.
authors.forename: W J
authors.initials: WJ
authors.lastname: Schnedl
authors.forename: E C
authors.initials: EC
authors.lastname: Reisinger
authors.forename: S
authors.initials: S
authors.lastname: Katzensteiner
authors.forename: R W
authors.initials: RW
authors.lastname: Lipp
authors.forename: F
authors.initials: F
authors.lastname: Schreiber
authors.forename: P
authors.initials: P
authors.lastname: Hopmeier
authors.forename: G J
authors.initials: GJ
authors.lastname: Krejs
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005188:False Negative Reactions; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006455:Hemoglobins, Abnormal / Q000032:analysis*; D006801:Humans
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin; D006455:Hemoglobins, Abnormal; C038278:hemoglobin O Padova