GENETIC EPIDEMIOLOGY OF SINGLE-GENE DEFECTS IN CHILE

We have studied the correlation between the ethnic structure and the p revalence of single gene defects in Chile. At present the Chilean popu lation is approximately 64% white and 35% Amerindian with traces of ot her admixture. Fewer than 4% of the Chilean population are foreign bor n. Investigations indicate that all severe diseases and many others wi thout impaired reproduction have mutation rates within the range of th e white population. Classical ethnic diseases are very rare. Autosomal recessive disorders have a wide range of variability: cystic fibrosis has a low incidence and PKU has a similar incidence to English rates. Only 30% of the inborn errors of metabolism have been described in Ch ilean medical publications, In addition, no Chilean haemoglobin or hap toglobin variants have been described. Some rare inherited diseases in Chilean human isolates have been described, including achromatopsia, chondrocalcinosis, and Creutzfeldt-Jakob disease, The prevalence of in trahepatic cholestasis of pregnancy and supernumerary nipples is the h ighest in the world and they are associated with aboriginal origin. Si ngle gene defects in Chile are probably shaped by factors related to i ts ethnic population structure. These local rare single gene defects m ay be good markers of population admixture for genetic epidemiological studies.