Deletion

Absence of a segment of DNA; may be as small as a single base or as large as a whole chromosome. (NCI Thesaurus)

Familial

A phenotype or trait that occurs with greater frequency in a given family than in the general population; familial traits may have a genetic and/or nongenetic etiology.

Population risk

The proportion of individuals in the general population who are affected with a particular disorder or who carry a certain gene; often discussed in the genetic counseling process as a comparison to the patient’s personal risk given his or her family history or other circumstances

Recurrence risk

In genetics, the likelihood that a hereditary trait or disorder present in one family member will occur again in other family members. This is distinguished from recurrence risk for cancer, which is the chance that a cancer that has been treated will recur.

Kindred

An extended family.

Domain

A specific physical region or amino acid sequence in a protein which is associated with a particular function or corresponding segment of DNA.

Informed consent

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. (NCI Thesaurus)

Mode of inheritance

The manner in which a genetic trait or disorder is passed from one generation to the next. Autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, multifactorial, and mitochondrial inheritance are examples. Each mode of inheritance results in a characteristic pattern of affected and unaffected family members. (NCI Thesaurus)

Transcription

The process of synthesizing messenger RNA (mRNA) from DNA. (NCI Thesaurus)

Microsatellite

Repetitive segments of DNA scattered throughout the genome in noncoding regions between genes or within genes (introns). They are often used as markers for linkage analysis because of their naturally occurring high variability in repeat number between individuals. These regions are inherently genetically unstable and susceptible to mutations. (NCI Thesaurus)

Gene

The basic unit of heredity that occupies a specific location on a chromosome. Each consists of nucleotides arranged in a linear manner. Most genes code for a specific protein or segment of protein leading to a particular characteristic or function. (NCI Thesaurus)

Susceptibility gene

A germline mutation that increases an individual’s susceptibility or predisposition to a certain disease or disorder. When such a mutation is inherited, development of symptoms is more likely, but not certain. Also called predisposing mutation. (NCI Thesaurus)

Cytogenetics

The study of the structure, function, and abnormalities of human chromosomes. (NCI Thesaurus)

Genotype

At its broadest level, genotype includes the entire genetic constitution of an individual. It is often applied more narrowly to the set of alleles present at one or more specific loci. (NCI Thesaurus)

Heterozygous genotype

Occurs when the two alleles at a particular gene locus are different. A heterozygous genotype may include one normal allele and one mutation, or two different mutations. The latter is called a compound heterozygote. (NCI Thesaurus)