special subjects
Clinical Uses of Genetics
Genetic Screening
Genetic screening may be indicated in populations at risk of a particular genetic disorder. The usual criteria for genetic screening are Genetic inheritance patterns are known. Effective therapy is available. Screening tests are sufficiently valid, reliable, sensitive and specific, noninvasive, and safe. Prevalence in a defined population must be high enough to justify the cost of screening. One aim of Preconception or Prenatal Carrier Testing of Parents is to identify asymptomatic parental heterozygotes carrying a gene for a recessive disorder. For example, Ashkenazi Jews are screened for Screening may be appropriate for people with a family history of a dominantly inherited disorder that manifests later in life, such as Huntington disease or cancers associated with abnormalities of theBRCA1andBRCA2genes. Screening clarifies the risk of developing the condition for that person, who can then make appropriate plans, such as for more frequent screening or preventive therapy. Screening may also be indicated when a family member is diagnosed with a genetic disorder. A person who is identified as a carrier can make informed decisions about reproduction. 