Genetic Carrier Testing

Genetic carrier testing includes tests for the heterozygous status of an inherited disorder in individuals who, although apparently healthy themselves, have a high risk of transmitting the genetic disorder to their offspring. Carrier testing will allow couples of childbearing age to make informed reproductive decisions. Genetic carrier tests are used by people who have a family history of an inherited disorder or carriership, reproductive partners of carriers and partners of individuals who have the disorder. A prerequisite for knowledge about a possible risk for relatives and the availability of testing is the dissemination of information in the family. Many factors impede the sharing of genetic information in families including lack of knowledge, persistent lay beliefs or poor relationships. In addition, several factors have been identified that interfere with decisions about genetic carrier testing, resulting in low uptake rates for carrier tests in high risk families.

Key concepts

  • Reproductive planning is the most important factor motivating genetic carrier testing.
  • Family disclosure of genetic information is a prerequisite to knowledge about the risk and availability of carrier testing.
  • Because of factors impeding the sharing of information in families and factors interfering with the decision about testing, the uptake for carrier testing in high-risk families is often lower than expected.
  • To minimize (time) constraints and maximize reproductive options, carrier testing before conception is advocated.

Keywords: carrier status; genetic testing; genetic risk; family communication; psychological impact

 References
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 Further Reading
    Ayme S, Macquart-Moulin G, Julian-Reynier C, Chabal F and Giraud F (1993) Diffusion of information about genetic risk within families. Neuromuscular Disorders 3: 571–574.
    Decruyenaere M, Evers-Kiebooms G, Denayer L and Welkenhuysen M (1998) Uptake and impact of carrier testing for cystic fibrosis. Community Genetics 1: 23–35.
    Eggers S, Pavanello RC, Passos-Bueno MR and Zatz M (1999) Genetic counselling for childless women at risk for Duchenne muscular dystrophy. American Journal of Medical Genetics 86: 447–453.
    Hayeems RZ, Bytautas JP and Miller FA (2008) A systematic review of the effects of disclosing carrier results generated through newborn screening. Journal of Genetic Counselling 17: 538–549.
    Lafayette D, Abuelo D, Passero MA and Tantravahi U (1999) Attitudes toward cystic fibrosis carrier and prenatal testing and utilization of carrier testing among relatives of individuals with cystic fibrosis. Journal of Genetic Counseling 8: 17–36.
    McConkie-Rosell A, Robinson H, Wake S et al. (1995) Dissemination of genetic risk information to relatives in the fragile X syndrome: guidelines for genetic counselling. American Journal of Medical Genetics 59: 426–430.
    Tedgard U (1998) Carrier testing and prenatal diagnosis of haemophilia – utilisation and psychological consequences. Haemophilia 4: 365–369.
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    Wilson BJ, Forrest K, van Teijlingen ER et al. (2004) Family communication about genetic risk: the little that is known. Community Genetics 7: 15–24.
    Wolff G, Back E, Arleth S and Rapp-Korner U (1989) Genetic counselling in families with inherited balanced translocations: experience with 36 families. Clinical Genetics 35: 404–416.
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Henneman, Lidewij, and Cornel, Martina(Sep 2009) Genetic Carrier Testing. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005627.pub2]