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NCI Dictionary of Genetics Terms

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NCI Dictionary of Genetics Terms


21 results found for: C



  • carrier  (KAYR-ee-er)
    In classical genetics, an individual who carries one deleterious allele for an autosomal recessive disorder. In clinical discussions, may refer to an individual who carries a deleterious allele that predisposes to disease.

  • carrier frequency  (KAYR-ee-er FREE-kwen-see)
    The proportion of individuals in a population who have a single copy of a specific recessive gene mutation; also sometimes applied to the prevalence of mutations in dominantly acting genes such as BRCA1 and BRCA2. Also called carrier rate.

  • carrier rate  (KAYR-ee-er rayt)
    The proportion of individuals in a population who have a single copy of a specific recessive gene mutation; also sometimes applied to the prevalence of mutations in dominantly acting genes such as BRCA1 and BRCA2. Also called carrier frequency.

  • chromosome  listen  (KROH-muh-some)
    Discrete physical structures inside a cell nucleus that consist of proteins and DNA organized into genes.

  • clone  (klone)
    An identical copy of a DNA sequence or entire gene; one or more cells derived from and identical to a single ancestor cell OR to isolate a gene or specific sequence of DNA.

  • CNV 
    Refers to the genetic trait involving the number of copies of a particular gene present in the genome of an individual. Genetic variants, including insertions, deletions, and duplications of segments of DNA, are also collectively referred to as CNVs. CNVs account for a significant proportion of the genetic variation between individuals. Also called copy number variant.

  • codon  (KOH-don)
    In DNA or RNA, a sequence of 3 consecutive nucleotides that codes for a specific amino acid or signals the termination of gene translation (stop or termination codon).

  • conformation-sensitive gel electrophoresis  (KON-for-MAY-shun-SEN-sih-tiv jel ee-LEK-troh-fuh-REE-sis)
    A type of mutation testing in which a segment of DNA is screened for mismatched pairing between normal and mutated base pairs. Also called CSGE.

  • congenital  listen  (kun-JEH-nih-tul)
    A condition or trait present at birth. It may be the result of genetic or non-genetic factors.

  • consanguinity  (KON-sang-GWIH-nih-tee)
    Genetic relatedness between individuals who are descendants of at least one common ancestor.

  • consent process  listen  (kun-SENT PRAH-ses)
    A process of information exchange between a clinician and an individual or their legal proxy designed to facilitate autonomous, informed decision making. The informed consent process for genetic testing should include an explanation of the medical and psychosocial risks, benefits, limitations, and potential implications of genetic analysis, a discussion of privacy, confidentiality, the documentation and handling of genetic test results, as well as options for managing the hereditary disease risk. Also called informed consent.

  • consultand  (kon-SUL-tand)
    An individual who presents for genetic counseling. Also called counselee.

  • copy number variant  (KAH-pee NUM-ber VAYR-ee-unt)
    Refers to the genetic trait involving the number of copies of a particular gene present in the genome of an individual. Genetic variants, including insertions, deletions, and duplications of segments of DNA, are also collectively referred to as copy number variants. Copy number variants account for a significant proportion of the genetic variation between individuals. Also called CNV.

  • cosegregation  (KOH-seh-greh-GAY-shun)
    The transmission, together, of 2 or more genes on the same chromosome, as a result of their being in very close physical proximity to one another (i.e., linked).

  • counselee  (kown-seh-LEE)
    An individual who presents for genetic counseling. Also called consultand.

  • Crohn disease-like reaction  (krone dih-ZEEZ-like ree-AK-shun)
    Discrete aggregates of lymphoid white blood cells, some with germinal centers and surrounding fibrosis, commonly found around some colorectal adenocarcinomas in the absence of a clinical or pathological diagnosis of Crohn disease. Also called Crohn-like reaction.

  • Crohn-like reaction  (krone-like ree-AK-shun)
    Discrete aggregates of lymphoid white blood cells, some with germinal centers and surrounding fibrosis, commonly found around some colorectal adenocarcinomas in the absence of a clinical or pathological diagnosis of Crohn disease. Also called Crohn disease-like reaction.

  • CSGE 
    A type of mutation testing in which a segment of DNA is screened for mismatched pairing between normal and mutated base pairs. Also called conformation-sensitive gel electrophoresis.

  • cutaneous leiomyoma  (kyoo-TAY-nee-us LY-oh-my-OH-muh)
    A benign tumor that arises from smooth muscle tissue in a hair follicle, forming a papule. Cutaneous leiomyomas (or leiomyomata) can be painful in the presence of cold or tactile stimuli.

  • cutaneous lichen amyloidosis  (kyoo-TAY-nee-us LY-ken A-muh-loy-DOH-sis)
    Itchy papules that are brownish-red in color and typically appear on the shins, thighs, feet, or neck.

  • cytogenetics  listen  (SY-toh-jeh-NEH-tix)
    The study of the structure, function, and abnormalities of human chromosomes.