Clinical and hematologic features of beta0-thalassemia (frameshift 41/42 mutation) in Thai patients.
OBJECTIVE
Frameshift 41/42 mutation is the most common mutation of beta0-thalassemia found in Thailand. We studied clinical and hematologic features in 84 patients and relatives with frameshift 41/42 to determine whether it is possible to predict phenotypic severity from genetic factors.


METHODS
The clinical phenotypes and hematologic data of Thai patients with frameshift 41/42 were studied. Alpha-thalassemia, Hb Constant Spring (HbCS) genes and the presence of Xmnl-Ggamma polymorphism were studied in patients who had mild symptoms.


RESULTS
Homozygotes for frameshift 41/42 and compound heterozygotes for frameshift 41/42 and beta0-thalassemia produced severe symptoms and have a thalassemia major phenotype. Combination of frameshift 41/42 and beta0-thalassemia or Hb E produced mild to moderate symptoms with thalassemia intermedia phenotype and severe symptoms with thalassemia major phenotype. The co-inheritance of beta-thalassemia or HbCS gene or the presence of Xmnl-Ggamma polymorphism was not associated with mild disease in patients with frameshift 41/42 and HbE.


CONCLUSIONS
The clinical phenotype of homozygotes for frameshift 41/42 and compound heterozygotes for frameshift 41/42 and beta0-thalassemia could be used to predict a severe phenotype with thalassemia major. However, the clinical phenotype of compound heterozygotes of frameshift 41/42 and beta0-thalassemia or Hb E were variable and could not be accurately predicted. Associations between concomitant alpha-thalassemia or HbCS of the presence of Xmnl-Ggamma polymorphism and a mild clinical phenotype are not apparent, indicating the involvement of other ameliorating determinants or genetic modifications.
Department of Pediatrics,Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkla 90110, Thailand. lvichai@ratree.psu.ac.th
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Laosombat
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Wongchanchailert
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Sattayasevana
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Wiriyasateinkul
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Fucharoen
D000483:Alleles; D002648:Child; D002675:Child, Preschool; D016368:Frameshift Mutation / Q000235:genetics*; D006446:Hemoglobin E / Q000009:adverse effects; D006801:Humans; D010641:Phenotype; D012720:Severity of Illness Index; D013785:Thailand / Q000453:epidemiology; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis / Q000235:genetics*
D006446:Hemoglobin E