tailieunhanh - Chapter 064. The Practice of Genetics in Clinical Medicine (Part 2)

Population Screening Mass genetic screening programs require tests of high enough sensitivity and specificity to be cost-effective. An effective screening program should fulfill the following criteria: that the tested disorder is prevalent and serious; that it can be influenced presymptomatically through lifestyle changes, screening, or medications; and that identification of risk does not result in undue discrimination or harm. Screening individuals of Jewish descent for the autosomal recessive neurodegenerative disorder Tay-Sachs disease has resulted in a dramatic decline in the incidence of this syndrome in the United States. On the other hand, screening for sickle cell disease or trait. | Chapter 064. The Practice of Genetics in Clinical Medicine Part 2 Population Screening Mass genetic screening programs require tests of high enough sensitivity and specificity to be cost-effective. An effective screening program should fulfill the following criteria that the tested disorder is prevalent and serious that it can be influenced presymptomatically through lifestyle changes screening or medications and that identification of risk does not result in undue discrimination or harm. Screening individuals of Jewish descent for the autosomal recessive neurodegenerative disorder Tay-Sachs disease has resulted in a dramatic decline in the incidence of this syndrome in the United States. On the other hand screening for sickle cell disease or trait in the African-American population has sometimes resulted in insurance and employment discrimination. Mass screening for complex genetic disorders can result in potential problems. For example cystic fibrosis is most commonly associated with alterations in AF508. This variant accounts for 30-80 of mutant alleles depending on the ethnic group. Nevertheless cystic fibrosis is associated with pronounced genetic heterogeneity with more than 1000 disease-related mutations. The American College of Medical Genetics recommends a panel of 23 alleles including the AF508 allele for routine diagnostic and carrier testing. Analysis for the less common cystic fibrosis-associated mutations would greatly impact the cost of testing without significantly influencing the effectiveness of mass screening. Nevertheless the individual who carries one of the less common cystic fibrosis-associated alterations will not benefit if testing is limited to a routine panel. Occupational health screening programs hold promise but also raise concerns about employment discrimination. These concerns were brought to light in 2001 when it was discovered that a railroad company was testing its employees without consent for a rare genetic condition that .