FURTHER MAPPING OF THE PROPERDIN DEFICIENCY GENE IN A TUNISIAN JEWISHFAMILY - EVIDENCE FOR GENETIC HOMOGENEITY

The properdin deficiency gene has been localized to Xp21.l-X(cen); how ever, it is not clear whether the mutation responsible for the disease co-maps exactly with the structural properdin gene. Based on a recent study on a total of six families, the gene was found linked to DXS255 (theta = 0.00). As only a few families have been studied, it is not k nown whether the same gene is responsible for the disease in all famil ies. In order to better localize the disease gene in Israel, we studie d a Tunisian Jewish family with properdin deficiency for linkage with various X-markers. A maximum lod score of 1.93 at theta = 0.00 was cal culated with the DXS7 probe while there was one recombination with DXS 255. This study helps to better localize the properdin deficiency gene to Xp11.3-p21.1 proximal to DXS255 locus and confirms that there is n o indication of genetic heterogeneity. Whether the properdin structura l gene (PFC) and properdin deficiency locus are one and the same await demonstration of mutations in the structural gene in patients with pr operdin deficiency.