Objective
Preimplantation Genetic Diagnosis (PGD) for β Thalassemia reveals a valid option for the prevention of the birth of an affected child. Preimplantation Genetic Diagnosis is also developed as a therapeutic tool for the cure of an affected child when combined with HLA typing. The purpose of the present report is to document our experience on PGD and PGD+HLA typing for β Thalassemia cases applied to our center.

Design
A retrospective study.

Materials and methods
Overall, twenty nine ovarian controlled hyperstimulation cycles (COH) were performed in 26 couples for β Thalassemia. In seven cycles PGD for β Thalassemia (Group I) was applied, where as in 22 cycles PGD for β Thalassemia combined with HLA typing (PGD+HLA typing; Group II) was performed. Totally 261 embryos were screened for β Thalassemia mutations including IVS-I -110 G/A, IVS-I -130 G/C, IVS-I -1 G/A, IVS-I -6 T/C, IVS-II -1 G/A, IVS-II -745 C/G, COD5 -CT, COD8 -AA, COD39 C/T, COD82 -G and -30 T/A. 215 embryos were further analysed for HLA compatibility after multiplex PCR by Minisequencing method and STR analysis. According to the results embryo transfer was performed with the disease-free and/or HLA compatible embryos.

Results
7/7 cycles in Group I, 14/22 cycles in Group II reached the embryo transfer stage. Unaffected embryos for transfer were detected in all PGD cycles in Group I, however in Group II, 8 transfers were cancelled due to the lack of HLA matched embryos. Overall, transfer of 37 disease free embryos resulted in 7 (2 birth, 3 term and 2 ongoing) pregnancies (33.3%) in 21 embryo transfers.

Conclusion
The results demonstrate that PGD is an efficient method for the prevention of the birth of affected children with β Thalassemia, providing an acceptable number of mutation free embryos for transfer. However, in case of a combined HLA typing, successful pregnancy is further limited by the number of HLA compatible embryos.