Journal des biomarqueurs moléculaires et du diagnostic

Microcytosis and Alpha and Beta Thalassaemia in Prospective Blood Donors of East Indian Descent in Trinidad and Tobago

Abstract

Sehlule V, Hasina M, Wayne L, George L, Angel A J V, Marie-Dominique HD, Marc R and Christian SM

Background: People of East Indian descent account for 40% of the Trinidad and Tobago (TT) population. Most came from Uttar-Pradesh and West Bengal in India where thalassaemia is prevalent. The thalassaemia carrier frequency and exact mutations are unknown in TT. Diagnostic DNA analysis is not routinely available.

Objective: To estimate the carrier frequency of thalassaemia among prospective blood donors.

Method: Blood samples were obtained from 125 prospective blood donors of East-Indian origin. CBC was done to screen for microcytosis(MCV≤83 fL). Microcytic samples had ferritin, transferrin saturation, haemoglobin electrophoresis, haemoglobin A2/F quantification and DNA analysis performed performed for thalassaemia.

Results: 72.4% subjects were male and 26.4% female. Microcytosis was found in 14 (11.2%) (9 males, 5 females). Among microcytic subjects, 11(78.6%) (8 males, 3 females) thalassaemia mutations were detected. The range MCV range was wider in β-thalassaemia (63.7-80.7 fL) than α-thalassaemia carriers (78.5-80.1 fL). All subjects with the α-globin gene mutation had the α3.7 deletion which is the commonest α-gene mutation in India. The people with β-thalassaemia mutations had IVS I-5 G/C (common in India) and IVS II-666 T/C.

Conclusion: There were a high percentage of thalassaemia carriers in microcytic individuals, thus showing the importance of testing for this disorder. A larger study is needed to determine the spectrum of α- and β-thalassaemia mutations, to analyze for correlation between the degree of microcytosis and specific genotype and for useful predictors of α- and β-globin gene mutations.