Sarcoidosis affects people of all racial and ethnic groups and occurs at all ages, although it usually develops before the age of 50 years, with the incidence peaking at 20 to 39 years. The incidence of Sarcoidosis varies widely throughout the world. The modern history of Sarcoidosis disease goes back to 1899 when the pioneering Norwegian dermatologist coined the term to describe skin nodules characterized by compact, sharply defined foci of epithelioid cells with large pale nuclei and also a few giant cells. Thinking this resembled sarcoma, he called the condition multiple benign sarcoid of the skin. This review article has focused on the underlaying mechanism which is responsible for occurance of Sarcoidosis. It also involved the genetic factors (genes) that are responsible for Sarcoidosis. Sarcoidosis has no known cause; although none of potential causes has been definitely confirmed, there is increasing evidence to support that one or more infectious agents may cause Sarcoidosis, although this organism may no longer be viable in the patient. The diagnosis of Sarcoidosis has been significantly aided by new technology. This includes the endobronchial ultrasound, which has been shown to increase the yield of needle aspiration of mediastinal and hilar lymph nodes. The positive emission tomography scan has proven useful for selecting possible biopsy sites by identifying organ involvement not appreciated by routine methodology. Emerging technologies and advances in genomics and proteomics will help to find the causes of Sarcoidosis in future, with the better understanding of pathogenesis of Sarcoidosis and to test new therapy for it.
Key words: Sarcoidosis, Genes, Diagnosis