Celocentesis for Early Prenatal Diagnosis in Couples at-Risk for beta-Thalassemia and Sicilian (delta beta)(0)-Thalassemia

The procedures commonly used for prenatal diagnosis (PND) of thalassemia are villocentesis or amniocentesis, respectively, at the 11th and 16th weeks of gestation. Their main limitation is essentially due to the late gestation week in which diagnosis is performed. The celomic cavity is accessible between the 7th and 9th weeks of gestation and it has been demonstrated that it contains embryonic erythroid precursor cells as a source of fetal DNA for earlier invasive PND of thalassemia and other monogenic diseases. In this study, we report the use of celomatic fluids obtained from nine women with high-risk pregnancies for Sicilian (delta beta)(0)-thalassemia [(delta beta)(0)-thal] deletion (NG_000007.3: g.64336_77738del13403) and beta-thalassemia (beta-thal). Fetal cells were isolated by a micromanipulator, and nested polymerase chain reaction (PCR) and short tandem repeats (STRs) analysis were performed. Prenatal diagnosis was successfully performed in all examined cases. One fetus was a compound heterozygote for (delta beta)(0)- and beta-thal, three fetuses were found to be carriers of beta-thal, four fetuses carriers of a Sicilian delta beta deletion, and one fetus without parental mutations. Accidentally, a rare case of paternal triploidy was observed. The genotypic analysis, carried out both by amniocentesis and on abortive tissue or after birth, showed concordance with results obtained on fetal celomic DNA. Our results unequivocally show that fetal DNA can be obtained by nucleated fetal cells present in the celomatic fluid and demonstrate, for the first time, that PND of Sicilian (delta beta)(0)-thal and beta-thal is feasible at an earlier time in pregnancy than other procedures.