The genetic basis of endometriosis

Family studies have long suggested a role for genetic factors in the aetiol ogy of endometriosis. The influence of genes on disease development has mai nly been researched independently of environmental factors, yet their inter action must play an important role. Greater exposure to retrograde menstrua tion and oestrogen is likely to increase the risk of endometriosis; toxic c ompounds such as dioxin may increase the risk, although the only direct evi dence has come from primate studies. Previous association studies implicate d GALT (a gene involved in galactose metabolism), and GSTM1 and NAT2 (genes encoding for the detoxification enzymes) as possible disease susceptibilit y genes. Recent findings have added to the evidence for the involvement of GSTM1 and NAT2, but have cast doubt on the role of GALT. However, the desig n of many genetic and epidemiological studies has been inadequate with resp ect to sample size, consistency in phenotype definition, and the choice of control populations. These features are likely to influence results, and co uld partly explain the lack of consistency in the findings. Future studies should use a consistent disease definition and be of appropriate epidemiolo gical design. Curr Opin Obstet Gynecol 13:309-314. (C) 2001 Lippincott Will iams & Wilkins.