Coexistence of Southeast Asian ovalocytosis and beta-thalassemia: a molecular and hematological analysis.
We describe hematological and molecular characterization of a Thai female who had Southeast Asian ovalocytosis (SAO) associated with beta+-thalassemia trait. The proband had mild microcytosis with Hb 12.9 g/dl, Hct 35.8%, MCV 74.4 fl, MCH 26.8 pg, MCHC 36.0 g/dl, and elevated Hb A2 (5.6%), characteristics of beta-thalassemia trait. Peripheral blood film examination revealed prominent ovalocytosis. However, a one-tube osmotic fragility (OF) test commonly used for thalassemia screening was negative and a normal OF curve was observed. Further polymerase chain reaction (PCR) analyses identified the beta(-28A-G) mutation in the beta-globin gene and a 27 bp deletion in erythrocyte band 3 protein gene, indicating a genetically compound heterozygote. Hematological data of the proband was comparatively presented with those of eight female and 15 male carriers of pure beta-thalassemia with the same mutation. The finding demonstrates that although the association of the SAO and beta-thalassemia does not produce a more severe clinical picture, this could lead to a mis-screening of beta-thalassemia using an OF test as a primary screening test. Additional blood film examination followed by PCR could help in the detection of this unusual genetic interaction in the region.
Fucharoen
Goonnapa
G
Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.
Fucharoen
Supan
S
Singsanan
Sanita
S
Sanchaisuriya
Kanokwan
K
D000328:Adult; D001457:Anion Exchange Protein 1, Erythrocyte / Q000235:genetics*; D004612:Elliptocytosis, Hereditary / Q000150:complications / Q000235:genetics*; D004913:Erythrocytes, Abnormal; D005260:Female; D005914:Globins / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008297:Male; D017384:Sequence Deletion; D013785:Thailand; D017086:beta-Thalassemia / Q000150:complications / Q000235:genetics*
D001457:Anion Exchange Protein 1, Erythrocyte; C454201:SLC4A1 protein, human; D005914:Globins