Prevalence, phenotype and inheritance of benign neutropenia in Arabs

ANCs were studied prospectively amongst a healthy indigenous population (n = 1032) from the United Arab Emirates undergoing a nation-wide sickle-cell and thalassemia screening program. The mean neutrophil count and the prevalence of benign neutropenia were compared by age, sex and amongst various tribes.The mean neutrophil count (× 109cells/L) was 3.3 (range 0.95–7.6). Benign neutropenia was present in 110 (10.7%) subjects of whom 24 (2.3%) individuals had moderate neutropenia (ANC 0.5 – 1.0 × 109 cells/L). In the 22 tribe-family groups, the prevalence of benign neutropenia varied between 0% and 38%. Benign neutropenia showed no difference in the frequency amongst the sexes (p = 0.23) and it was independent of age (Spearman's rho = 0.05, p = 0.13). The age-related mean neutrophil count was the lowest in Arabs when compared with other ethnic groups (Blacks, Europeans and Mexicans). The inheritance of benign neutropenia was consistent with an autosomal dominant pattern; however, the diversity of observed phenotypes suggested the presence of more than one genetic variant for this trait.Arabs have a high prevalence of benign neutropenia that may be inherited as an autosomal dominant trait.Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1.5 × 109 cells/L. During the second half of the 20th century, this cutoff value was derived from clinical trials which were evaluating the myelosuppressive effects of chemotherapy. Most patients recruited for these seminal studies were of European origin; subsequently, it was realized that this 'standard' caused an excessive number of healthy individuals of African descent to be mislabeled as neutropenic. The neutropenia that is not associated with an increased risk of infections has been called benign neutropenia (BN). Using this description, BN has been reported in up to 30% of people of African origin [1]. Recently, the prevalence of neutropenia in American Blacks was found to be 4.4% compared to 0.8% in Whit