Fetal hydrops in Sardinia: implications for genetic counselling

This paper describes the first case of Hb Bart's hydrops fetalis syndrome in the Sardinian population. Despite the high frequency of α-thalassemia, fetal hydrops is extraordinarily rare in the Sardinian population because α-thalassemia is more usually the result of the single α-thalassemia globin gene deletion and is very rarely produced by the deletion of two α-globin genes. The fetus, the product of a consanguineous marriage at risk for β-thalassemia, was monitored by chorionic villi DNA analysis which detected the heterozygous state for the codon 39 nonsense mutation. Follow-up ultrasound examination showed fetal hydrops, which led us to carry out further investigation. Hemoglobin and α-globin gene analysis on cord blood obtained by cordocentesis revealed the homozygous state for the most common deletion α°-thalassemia in Mediterranean populations. Retrospective evaluation of the father's hematological features showed very low MCH-MCV for a β-thalassemia carrier which may indicate coinherited α-thalassemia. These findings indicate that careful evaluation of red cell indices of parents at risk for β-thalassemia and adequate consideration of the consanguinity may point to co-inherited α-thalassemia and lead to the appropriate analysis.