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.
Laosombat
V
V
Department of Pediatrics,Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkla 90110, Thailand. lvichai@ratree.psu.ac.th
Wongchanchailert
M
M
Sattayasevana
B
B
Wiriyasateinkul
A
A
Fucharoen
S
S
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