Proband

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Proband is a term used most often in medical genetics and other medical fields to denote a particular subject (person or animal) being studied or reported on. On pedigrees, the proband is noted with an arrow and the box (male) or circle (female) shaded accordingly. It is important to denote the proband, so that the relationship to other individuals can be seen and patterns established.

Proband is usually the first affected family member who seeks medical attention for a genetic disorder. Between the ancestors of the proband, there are other subjects with the manifest disease, but they might be unknown due to the lack of information regarding those individuals or the disease at the time they lived. Other ancestors might be undiagnosed due to the incomplete penetrance or variable expressivity.

The diagnostic of the proband raise the level of suspicion for the proband's relatives and some of them may be diagnosed with the same disease. Conventionally, when drawing a pedigree chart, instead of the first diagnosed person, the proband may be chosen between the manifestly ill ancestors (parents, grandparents) from the first generation where the disease is found.