Consultand versus Proband

Meaning of the Terms Consultand and Proband in Genetic Counseling

In genetic mapping studies, the Consultand or Proband are terms used to define the individual who is presenting for the appointment of genetic counseling.

More specifically, the Consultand is the person with the appointment in the clinical setting, this person is seeking genomic health information but does not have a known diagnosis of the disorder for which s/he is seeking consultation.

This person is identified on the pedigree Opens in new window with an arrow but is not identified in the pedigree legend with the medical disease/disorder.

The consultand can be healthy or a person with medical conditions but not currently diagnosed with a condition warranting evaluation.

In contrast, the Proband is the affected individual who manifests symptoms of a particular disease/condition that brings the family to medical attention (National Library of Medicine, 2014).

Often the proband is a child, but s/he may also be the consultand or a more distant relative.

It is not uncommon for an individual to be both a consultand and a proband. For example, a Caucasian female presenting with a history of breast cancer diagnosed at age 35 may have genetic testing that reveals she has inherited a hereditary breast cancer Opens in new window syndrome (BRCA) mutation.

In this case, her pedigree Opens in new window would display an arrow designating her as the proband, with the letter P at the end of the arrow (see Figure).

Identifying the proband is important in genetic mapping studies and research. Some researchers use the term propositus (propositi in plural) interchangeably with proband(s).

The index case is a term used in genetic research to describe the first affected person to be studied in the family.

As earlier mentioned, sometimes an individual is both a proband and the consultand. In addition, there can be two probands in a family if each independently brings that branch of the family to medical attention.

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    Adapted from Thompson & Thompson Genetics in Medicine E-Book By Robert L. Nussbaum, Roderick R. McInnes, Huntington F Willard