According to the National Institutes of Health:
An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop. . . Genes come in pairs. Recessive inheritance means both genes in a pair must be defective to cause disease. People with only one defective gene in the pair are considered carriers. However, they can pass the abnormal gene to their children.
While some new treatments hold promise, the deteriorating health of its sufferers often lead to a desperate scramble for scarce organ transplants. The cost to America's already over-burdened health care system of constant hospitalizations and organ transplant surgeries is in the billions of dollars. Genetic testing also offers hope. But its results can be confusing, ambiguous and heartbreaking to couples forced to decide whether to carry a pregnancy to term based on geneticists' inability to predict the extent of the disease, or the course it will take in any given child. (See a 2002 review of the state of prenatal CF testing for the Journal of Pediatrics, Philip M. Farrell and Norman Fost).
Ethnic inbreeding is not, however, about "race." The latter is a concept that contemporary geneticists now recognize as a figment of 18th century slave trader's stunted imaginations. The demand for slaves encouraged them to slice the world in three parts: Caucasoids, Negroids and Mongoloids.
However, modern geneticists call such racial thinking hogwash.
What is real are the thousands of regional population groups, whose adaptation to unique environments and intermarriage give them a similar genetic signature. While sub-Saharan Africans share the same dark complexion, only those inhabiting malarial climates suffer from sickle-cell anemia. Northern Europeans and East Africans share a lactose-intolerance rate of 5% because they are cattle and dairy-producing cultures. West Africans, who did not develop dairy farming because of the scourge of the tsetse fly have a lactose-intolerance rate closer to 85%, numbers comparable to what one finds among many Asian populations.
Northern Europeans who marry those of Mediterranean descent, West Africans who marry East Africans, and Ashkenazic Jews who marry Mizrahim dramatically reduce their chances of giving birth to offsprings suffering from autosomal recessive disorders. Such health risks become almost non-existent when Americans take advantage of the multi-ethnic society that we have become, and seek out spouses whose ancestors come from different continents all together.
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Social Taboos Thwart Cures for Genetic Disorders