A comprehensive study on the major mutations in glucose-6-phosphate dehydrogenase-deficient polymorphic variants identified in the coastal provinces of Caspian Sea in the north of Iran.

Background: The aim of this study was the molecular analysis of G6PD patients for G6PD mutations in the coastal provinces of the Caspian Sea in north of Iran.

Methods: Studies on G6PD deficiency in the coastal provinces of the Caspian Sea in Iran were performed in 248 patients with a history of favism, in Mazandaran, Golestan and Gillan provinces, which contributed 74, 71 and 103 samples, respectively. Three different major polymorphic variants were determined by molecular analysis, using SSCP, sequencing and PCR-RFLP methods. Firstly, all Mazandaranian samples were searched for the Mediterranean mutation by PCR-RFLP method. The remaining samples of the Mazandaran province were analysed by SSCP followed by sequencing for other mutations. Then, our research was expanded in two other provinces, Golestan and Gillan, by the PCR-RFLP method.

Results: Three different major polymorphic variants were found: G6PD Mediterranean 75.4% (187 out of 248), G6PD Chatham 19.76% (49 out of 248), G6PD Cosenza 2.02% (5 out of 248) and 7 samples out of 248 remained unknown. Also, there was no significant difference in the incidence of various G6PD polymorphic variants with mean age, and various blood work values such as Hb, WBC and MCV between two major variants (p>0.20).

Conclusions: These results which are the first molecular investigation in north of Iran indicate a higher prevalence of G6PD Chatham in this large Iranian population than anywhere else in the world. The distribution of these G6PD variants is more similar to that found in an Italian population (80-84% for Mediterranean, 20% for Chatham and 1.9% for Cosenza mutation). Although the origin of Iranian population is rather uncertain, the closer similarity of the mutation spectrum to Italian rather than Middle Eastern population may indicate that these populations have a common ancestral origin.