Causes and Associated Syndromes
David W. Smith and M. Michael Cohen hypothesized the widow's peak hairline to be an anomaly that results from a lower-than-usual point of intersection of the bilateral periorbital fields of hair-growth suppression on the forehead. This can occur because the periorbital fields of hair-growth suppression are smaller than usual, or because they are more widely spaced. Wide spacing also explains the association between ocular hypertelorism – that is, the eyes being abnormally far apart – and widow's peak; this was suggested by findings in an unusual case of ocular hypertelorism in which surrounding scalp-hair growth was suppressed by an ectopic (displaced) eye. Widow's peaks are a symptom of Donnai-Barrow syndrome, a rare genetic disorder caused by mutations in the LRP2 gene. Other genetic syndromes occasionally associated with widow's peaks include Waardenburg syndrome and Aarskog syndrome.
A study of females conducted by Nusbaum and Fuentefria in 2009 found that 81% had a widow's peak.
Read more about this topic: Widow's Peak