[Current trends in hemoglobin genetic diseases]

The current aspects of genetic diseases of hemoglobin are as follows. (1) The localisation and the dimension of at-risk populations for sickle cell disease and thalassemia in metropolitan France are not exactly known. However, some recent epidemiological studies and preliminary results of studies being currently underway allow to delimitate the problem. The at-risk populations are localized in the parisian area, in Provence-Côte d'Azur, in the Lyon and Grenoble areas, in Lorraine, Alsace and the Northern part of France. The number of heterozygotes for these diseases is situated between 250,000 and 350,000. The number of homozygotes born each year is between 100 and 150. More than 250 homozygous thalassemia patients and probably 2,000 to 3,000 sickle cell patients are living at this time in metropolitan France. (2) The transgenic mouse model is an experimental tool which allowed important advances in the knowledge of the hemoglobin human genome. Thus, we now have lines of mice expressing human fetal (g genes) and human adult (b genes) hemoglobins. Recently, enhancer sequences have been identified in 5' to the embryonic gene epsilon. When this region, named locus-region-control (LCR), is inserted along with g and b globin genes, their expression is observed at a very high level. The main objective of this technique is to obtain mouse model for sickle cell disease and thalassemia for studies on the pathophysiology and the therapy of these diseases.(ABSTRACT TRUNCATED AT 250 WORDS)