Prenatal diagnosis of beta-thalassemia in the West Bank and Gaza

ABSTRACT

This study focuses on the genetic aspect of beta-thalassemia among 88 at risk couples from the West Bank and Gaza, and the attitude of these couples toward prenatal diagnosis and its outcome as a preventive method. We tested 130 prenatal samples for beta-thalassemia during the period from January 1999 to July 2005. We performed prenatal diagnosis in these cases using the amplification refractory mutation system, as well as beta-globin gene sequencing as a conformational method. We drew a chorionic villus sample [CVS] for 1st trimester pregnant women and amniotic fluid [AF] for those in the 2nd trimester depending on the stage the pregnant woman contacted our lab. The DNA analysis of 130 prenatal samples revealed 25 [19.2%] cases of beta-thalassemia major and 67 [51.5%] cases of beta-thalassemia carriers, while the remaining 38 [29.2%] were normal. The 25 affected fetuses were aborted according to the wishes of the parents. In the tested 88 couples, 14 mutations of beta-thalassemia were identified. These mutations and their frequencies were IVSI-110 [22.2%], IVSI-6 [13.6%], Cd37 [12%], IVSI-I [9.7%], IVSII-1 [6.2%], Cd39 [9%], Cd6 [sickle cell mutation] [8.5%], Cd5 [8%], Cd8/9 [2.8%], Cd106/107 [2.8%], -30 promoter [1.1%], -88 promoter [1.1%], IVSI [-1] [2.3%] and IVSI-5 [0.6%]. We found that in 77.3% of the couples, both the mother and the father carry the same type of mutation while 22.7% of them carry different mutations. We found 77.9% consanguinity among the couples. We found very good acceptability for prenatal diagnosis in beta-thalassemia afflicted families. All couples with affected fetuses opted for abortion. The spectrum of mutations in the tested couples revealed several similarities to neighboring countries with -88 promoter mutation reported for the first time in our region