Incidence of β-thalassemia carrier on 1495 couples in preconceptional period.

OBJECTIVE: This research, conducted on 1495 couples in preconceptional period, demonstrates how the study of globular resistance of erythrocytes (GRO) is not a first choice test and not useful as other more accurate tests to identify subjects with β-thalassemia trait. Instead, the complete blood count (CBC) and the evaluation of HbA, HbA2 and HbF by high pressure liquid chromatography (HPLC) are essential. METHODS: Each couple arrived in our laboratory to screen for β thalassemia. In case of patients with positive (240) or doubtful (112) results, we studied β-globin gene. RESULTS: Of the 2990 subjects examined, we found 280 subjects with β-thalassemia trait (9.36%). During biochemical tests, among 112 subjects with doubtful--normal GRO or altered GRO--results, 40 of them resulted positive for the molecular analysis, while 72 of them did not show mutations in β-globin genes. The 2710 samples with non-carriers of β-thalassemia trait presented as mean evaluation of HbA2 2.6%, while the 280 subjects with β-thalassemia trait presented as mean evaluation of HbA2 4.8%. Molecular study showed that the β thalassemia phenotype is caused by a small number of mutations, whose regional distribution is typical. CONCLUSIONS: In the presence of thalassemic parameters in the CBC, the accurate and precise quantification of hemoglobin HbA2 is essential for the diagnosis of β-thalassemia trait. DNA mutation analysis provides the most effective way to detect primary gene mutations. The mutations identified in this work can be identified with a simple and inexpensive kit. This means, in economic terms, a significant savings for health spending.