Molecular Basis and Prenatal Diagnosis of β-thalassemia Among Balouch Population in Iran

Objective: To determine the molecular spectrum of β-thalassemia mutations among at-risk Balouch couples in Iran.

Methods: Mutations' detection in DNAs extracted from the blood of partners of at-risk couples was characterized, and chorion villus sampling by amplification refractory mutation system and DNA sequencing was performed. Fetal diagnosis was also confirmed by linkage analysis.

Results: Out of a total of 1234 at-risk Balouch couples referred to the center for prenatal diagnosis (PND) from June 2002 to June 2010, a high percentage of '67.4%' were from consanguineous marriages and 37.4% had between one and four affected children. The trend in referring gradually increased from 34 cases in 2002 to 357 cases in 2010. The astonishing finding was that, unlike most previous studies, only IVS 1-5 with an unusual frequency of 87.20% along with codon 8/9 (+G) with 4% constitutes about 91% of mutations. Altogether, 729 PNDs were made in 583 couples, 25% of whom had over one PND, and surprisingly five PNDs were made in the same woman within just 8 years.

Conclusion: Regarding the limited types of frequent mutations among Balouch population, it is hopefully believed that the incidence of β-thalassemia could be controlled by a correct diagnosis in the due time.