Systemic Sarcoidosis: Sociodemographic and Genetic Characteristics in a Tunisian Population

Background: Sarcoidosis is a multi-systemic granulomatosis of unknown cause, characterized by a clinical polymorphism. It results from interplay of environmental and genetic factors. Objective: The aim of our study was to describe sociodemographic and genetic characteristics in Tunisian patients with sarcoidosis. Methods: We conducted a retrospective study of patients with sarcoidosis followed in the internal medicine and neurology departments at the Military Hospital of Tunis. We collected epidemiological characteristics. Genetic study concerned only patients who accepted to participate. DNA extraction was performed from whole blood. HLA class II typing and gene mutation testing of the ACE gene were also performed. Results: Our study concerned 50 patients. The mediastino-pulmonary involvement was the most frequent (72.3%), followed by neurological involvement (58.5%), cutaneous involvement (50.8%) and ophthalmological involvement (40%). Genetic analysis showed a high frequency of the HLA DRB1 * 1501 allele (38%), DD genotype (30%) and D allele (54%) of the ACE gene. Treatment with corticosteroids was most often used 73.85%. The evolution was favorable in 13 cases (26.15%), and stable in 63% of cases. Conclusion: sociodemographic and genetic characteristic are variable from one ethnic to another. Advances in genotyping and statistical analysis are helping to elucidate the genetics of sarcoidosis.