In medical genetics and other medical fields, a proband, propositus (male proband), or proposita (female proband) is a particular subject (human or other animal) being studied or reported on. On pedigrees, the proband is noted with a triangle (male) or circle (female) shaded accordingly. Denoting the proband is important, so the relationship to other individuals can be seen and patterns established.
In most cases, the proband is the first affected family member who seeks medical attention for a genetic disorder.