[Antenatal diagnosis of sickle-cell anaemia by DNA analysis of amniotic fluid cells. A preliminary study in the French West-Indies (author's transl)].

: The genetic polymorphism previously reported to be associated with the sickle-cell (beta S) gene in black U.S.A. citizens was studied in the population of two French West-Indies islands in order to evaluate its potential application to the antenatal diagnosis of sickle-cell anaemia. The polymorphism consists of a change in the DNA sequences located near the 3' end of the beta globin gene. The change can be detected by means of the restriction endonuclease Hpa I. When cellular DNA is digested with this enzyme, the beta globin gene is contained in a DNA fragment measuring either 7.6 or 13.0 kilobases (kb). In 70% of SS homozygous subjects in Martinique and 57% in Guadeloupe the beta S gene was carried by a 13.0 kb DNA fragment, whereas the normal beta A gene was carried by a 7.6 kb DNA fragment. This polymorphism would make it possible to detect the foetal beta S gene in the DNA of amniotic fluid cells by linkage analysis.