Epidemiology, Pathogenesis and Diagnosis of Aplastic Anaemia.

T incidence of aplastic anaemia shows geographical variability. The incidence aplastic anemia varied from 1052.7% among patients with pancytopenia.1 The incidence of severe and moderate AA was reported in 33.33% and 57.14% of cases respectively in from northern districts of West Bengal.2 One of the centres in India reported that aplastic anaemia accounted for 20-30% cases’ presenting with pancytopenia.3 The frequency of aplastic anaemia seen in hospitals of Asian countries is much higher than reported from the West, but the precise incidence of this disorder in India is not known. While incidence of aplastic anaemia (AA) in Europe and North America has been found to be low in prospective studies, reported as approximately 2 per million population per year4 in India and other Asian countries, it is about 2-3 times higher5 and could be as high as 6 to 8 per million population per year. The overall incidence of AA was 2.34 cases per million population per year in Barcelona and mortality at 2 years was nearly one death per million per year. Both incidence and mortality was shown to increase with age.6 There was a biphasic age distribution with peaks between the ages of 15 and 25 years and a second smaller peak in incidence was noted after age 60 years with no significant difference in incidence between men and women.7 Aplastic anaemia affects people of all ages and all races. The variability in incidence rates in developing countries, is uncertain. However, exposure to environmental f a c t o r s i n c l u d i n g v i r u s e s , d r u g s and chemicals, genetic background, diagnostic criteria, and study designs may be contributory. The median age of 8 years is consistently observed in various studies done from different regions6,8. Recently, the frequency of Fanconi anaemia reported was 16.6%9 in Pakistan due to increased consanguinity, which is higher than reported in Western literature but similar to the studies from India.10,11