[Incidental diagnosis of homozygous alpha-zero thalassemia in a 21 week old fetus].

A fetus with signs of hydrops fetalis syndrome of unknown etiology, has been studied at 21 weeks. In fetal blood, total absence of HbA and HbF, presence of Hb Bart's, Hb Portland and HbH argued in favor of alpha zero-thalassemia syndrome. Because thalassemia syndromes were transmitted in a mendelian autosomal fashion, we studied the parents. Results suggest that the father was carrier of heterozygous alpha zero-thalassemia syndrome and the mother of hemoglobin H disease (and also heterozygous HbE). Neither of them was aware of being carrier of the disease but this results explain the fetal homozygous alpha zero-thalassemia.