The Most Common Types of 3.7 Kilobase Deletion in the Iranian Population.

The 3.7 kb deletion is the most common known mutation in the α-globin gene cluster worldwide. The aim of this study is to investigate the most common types of 3.7 kb deletions in the Iranian population and, on the other hand, to compare the extent of deletion of the different reported types.

In this study, 50 Iranian α-thalassemia carriers in whom the 3.7 kb deletion had been previously identified by multiplex gap PCR, were further investigated by MLPA. A map of the region where the 3.7 kb deletion occurs was also created and the extents of the reported types were compared.

Approximately 90% of chromosomes with 3.7 kb deletion in this study had MLPA type D and 10% had MLPA type F. This study showed that subtype I of the 3.7 kb deletion reported by Higgs and his coworkers can be classified into at least 5 MLPA types.

The results of this study can be used to complete the information on the distribution of the 3.7 kb deletion subtypes in different populations. Investigation of further populations using higher resolution methods may lead to more information being obtained in this field.