Effects of α-thalassaemia mutations on the haematological parameters of β-thalassaemia carriers.
BACKGROUND
Thalassaemia is a haemoglobin disorder caused by a reduction in, or a complete absence of, the production of α- or β-globin genes. Detection of β-thalassaemia carriers is the first step in the prenatal diagnosis of the disease and is based primarily on the differences between levels of blood cell indices. Since co-inheritance of β- and α-thalassaemia mutations modulates the haematological parameters of heterozygote β-thalassaemia indices, understanding the influence of this interaction is helpful for identification of disease carriers.


OBJECTIVE
To determine the effects of α-thalassaemia mutations on the haematological parameters of β-thalassaemia carriers.


METHODS
We used gap-PCR and amplification refractory mutation system techniques to find any α- and/or β-thalassaemia mutations in 270 subjects who were suspected to be thalassaemia carriers. The mean values of the haematological parameters in α, β-thalassaemia and β-thalassaemia carriers were compared.


RESULTS
Significant differences in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and HbA2 were found between the two groups. Patients who were α, β-thalassaemia carriers had higher mean values of MCV and MCH, whereas HbA2 levels were higher in simple β-thalassaemia. No marked differences were found in mean cell haemoglobin (Hb) concentration and Hb blood cell indices. The value of MCV, MCH and HbA2 were significantly different between α,β-thalassaemia and simple β-thalassaemia in men and women, but the mean values of Hb in the two groups differed markedly only in men.


CONCLUSIONS
We conclude that co-inheritance of α- and β-thalassaemia mutations may result in misdiagnosis of β-thalassaemia carriers. Therefore, in genetic counselling of patients with a near-normal range of blood cell indices the possibility that they may carry α, β-thalassaemia mutations must be considered.
Physiology Research Center, Kerman University of Medical Sciences, Kerman, Iran.
Nasrollah
N
Saleh-Gohari
Genetic Laboratory, Afzalipour Hospital, Kerman, Iran.
Maryam
M
Khademi Bami
Department of Biostatistics and Epidemiology, Research Centre for Modelling in Health, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
Roya
R
Nikbakht
Department of Chemistry, Graduate University of Advanced Technology, Kerman, Iran.
Hassan
H
Karimi-Maleh
D015415:Biomarkers / Q000097:blood; D004252:DNA Mutational Analysis; D004909:Erythrocyte Indices; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005787:Gene Frequency; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006443:Hemoglobin A2 / Q000235:genetics* / Q000378:metabolism*; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation; D010641:Phenotype; D011237:Predictive Value of Tests; D017085:alpha-Thalassemia / Q000097:blood* / Q000175:diagnosis / Q000235:genetics*; D017086:beta-Thalassemia / Q000097:blood* / Q000175:diagnosis / Q000235:genetics*
D015415:Biomarkers; D005819:Genetic Markers; D006443:Hemoglobin A2
BLOOD CULTURE; BLOOD RHEOLOGY; BLOOD TRANSFUSION; BLOOD VESSELS