Genotyping of alpha-thalassemia in microcytic hypochromic anemia patients from North India.
Microcytic hypochromic anemia is a common condition in clinical practice and alpha-thalassemia has to be considered as a differential diagnosis. Molecular diagnosis of alpha-thalassemia is possible by polymerase chain reaction. The aim of this study was to evaluate the frequency of alpha-gene numbers in subjects with microcytosis. In total, 276 subjects with microcytic hypochromic anemia [MCV<80fl; MCH<27pg] were studied. These include 125 with thalassemia trait, 48 with thalassemia major, 26 with sickle-cell thalassemia, 15 with E beta-thalassemia, 40 with iron-deficiency anemia, 8 with another hemolytic anemia, and 14 patients with no definite diagnosis. Genotyping for -alpha3.7 deletion, -alpha4.2 deletion, Hb Constant Spring, and a-triplications was done with polymerase chain reaction. The overall frequency of -alpha3.7 deletion in 276 individuals is 12.7%. The calculated allele frequency for a-thalassemia is 0.09. The subgroup analysis showed that co-inheritance of a-deletion is more frequent with the sickle-cell mutation than in other groups. We were able to diagnose 1/3 of unexplained cases of microcytosis as a-thalassemia carriers. The a-gene mutation is quite common in the Indian subcontinent. Molecular genotyping of a-thalassemia helps to diagnose unexplained microcytosis, and thus prevents unnecessary iron supplementation.
Sankar
Vaikam H
VH
Department of Genetics, Sanjay Gandhi Post-graduate Institute of Medical Sciences, Lucknow, India.
Arya
Vandana
V
Tewari
Depshikha
D
Gupta
Usha R
UR
Pradhan
Mandakini
M
Agarwal
Sarita
S
D000747:Anemia, Hypochromic / Q000175:diagnosis*; D004252:DNA Mutational Analysis; D005817:Genetic Counseling; D005838:Genotype; D006801:Humans; D007194:India; D015995:Prevalence; D017085:alpha-Thalassemia / Q000235:genetics*