Vol. 17: Summer, 1999
Genetic Cancer Syndromes
Glossary
Autosomal disease - a disease encoded by a gene on a non-sex chromosome
Candidate gene - a gene thought to be a disease-causing gene, which maps to a region known to be linked to the disease
Carrier - an individual who carries one copy of a defective gene
Dominant (trait) - a condition expressed in individuals who have one copy of a defective gene
Expressivity - the degree to which a mutant gene is expressed; variable expressivity is characteristic of autosomal dominant diseases
Familial - any trait that is more common in relatives of an affected individual than in the general population; could be of environmental and/or genetic cause
Genetic screening - testing on a population basis for a genetic trait
Heterozygote - an individual who has two different forms of a gene at a given locus; i.e., different forms of a gene on two homologous chromosomes
Homozygote - an individual who has two identical forms of a gene at a given locus; i.e., the identical form of a gene on two homologous chromosomes
Linkage - the close physical association of two different genes, such that they tend to be inherited together
Missense mutation - a single DNA base pair change which results in a different amino acid coded for in a protein
Multifactorial inheritance - due to the influence of multiple genes and environmental influences
Mutation - a permanent genetic change in the genetic code of a person
Nonpenetrance - absence of signs of a disease usually caused by mutant gene(s); penetrance is an all-or-none phenomenon
Nonsense mutation - a single DNA base pair change which results in a premature stop codon; a truncated protein may be produced
Oncogene - a gene derived from a proto-oncogene, only one copy of which is necessary to cause cancer (e.g. RET gene mutation in MEN2)
Penetrance - the observable expression of a mutant gene
Point mutation - substitution of one DNA base pair for another
Polygenic diseases - caused by the influences of multiple genes
Polymorphism - the normal, i.e., non-disease causing, variation of DNA
Proband - the affected individual in a family who first comes to medical attention
Proto-oncogene - a normal gene which undergoes change to become a cancer causing gene (oncogene)
Recessive (trait) - a condition which is expressed only in individuals with two copies of a mutant gene
Tumor suppressor gene - a normal gene, both copies of which must be lost to cause cancer. Individuals from a cancer syndrome family may inherit the "absence" of one copy of the gene, and when the second copy is lost randomly in life, cancer can occur (e.g. the retinoblastoma gene); most familial cancer syndromes are associated with tumor suppressor genes
The Genetic Drift Newsletter is not copyrighted. Readers are free to duplicate all or parts of its contents. The Genetic Drift Newsletter is published semiannually by the Mountain States Genetics Network for associates & those interested in Human Genetics. In accordance with accepted publication standards, we request acknowledgement in print of any article reproduced in another publication. The views expressed in the newsletter do not necessarily reflect local, state, or federal policy. For additional information, contact Carol Clericuzio, M.D., Editor, Department of Pediatrics, The University of New Mexico, Albuquerque, NM, 87131
Genetic Cancer Syndromes
Table of Contents
Introduction
Identifying Patients at Risk
Breast/Ovarian Cancer
Colorectal Cancer
Other Familial Cancers
Web Links
Cancer Genetic Services
Current Research Studies
Glossary
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