The Screening of Chinese Cord Blood for Haemoglobinopathies

Abstract

The frequency of haemoglobinopathies among the Hong Kong Chinese newborn was examined by screening 932 consecutive cord blood samples by electrophoresis. The findings indicate that 49 (5.2%) had electrophoretic abnormalities, of which 39 (4.2%) demonstrated the presence of Hb Bart’s. 14 of these 39 babies were re-investigated after 1 year and all were proven to carry the α-thalassaemia gene. This is the first study in which Chinese babies with Hb Bart’s in cord blood had the diagnosis of α-thalassaemia trait confirmed in later life. 3 out of 4 other babies had different haemoglobin variants, namely Hb α^Q, Hb J and Hb New York. 1 out of the 6 babies who had elevated A₂ levels at birth was found to carry the β-thalassaemia trait. None had a serious haemoglobinopathy.

Prevalence and Genotypes of α- and β-Thalassemia Carriers in Hong Kong — Implications for Population Screening

“…11 Thalassemias are common in southern China. [12][13][14] In the population we screened, 4.6 percent (95 percent confidence interval, 3.6 to 5.6 percent) were *Six subjects were carriers of both a -and b -thalassemia mutations, three had hemoglobin H disease with deletion of three a -globin genes, and five were carriers of triplicated a -globin genes. heterozygous carriers of a-thalassemia involving either the (--SEA ) deletion or a deletion of the complete z-a-globin gene cluster (Tables 1 and 2) and were therefore at risk of conceiving fetuses with hemoglobin Bart's hydrops fetalis syndrome (absence of all four a-globin genes; commonly, (--SEA /--SEA ).…”

Prenatal diagnosis of thalassemia in the Chinese

“…In Taiwan, 5-7% of the general population carry the thalassemic gene. Most cases are found in people who immigrated from South China [14]. The incidence of ␣-thalassemia-1 of SEA type is 3-5%.…”