Molecular detection of Spanish δβ-thalassemia associated with β-thalassemia identified during prenatal diagnosis

Backgroundβ-Thalassemia is one of the most common single gene disorders and is widely distributed in the Mediterranean region. The δβ-thalassemias are a rare group of disorders, however in Spain the Spanish δβ0 thalassemia that removes 114 kb of β-globin cluster is quite frequent.MethodsTo establish a molecular diagnosis of β-thalassemia in a second-trimester fetus from a couple who are β-thalassemia carriers, a rapid real-time PCR method was performed to detect major mutations prevalent in people of the Mediterranean basin (IVS I-1, IVS I-6, IVS I-110, CD-6, CD-37, and CD-39). The Spanish δβ0 deletion was detected using PCR with deletion-specific primers.ResultsThe father was diagnosed as a carrier for the IVSI-6 (T > C) mutation and the mother as carrier for the Spanish δβ0 deletion. The fetus was a compound heterozygote for both those mutations. The phenotype of compound heterozygosity for δβ/β-thalassemia can range from mild thalassemia intermedia to thalassemia major. After confirming these results in the DNA from amniocentesis obtained at the 20th week of gestation, the couple decided to terminate the pregnancy.ConclusionsThis paper reports the first molecular characterization of Spanishδβ0-thalassemia associated with β-thalassemia IVSI-6, and confirms the importance of prenatal genetic testing for single gene disorder such as β-thalassemia.