Sulcus vocalis in monozygotic twins.

Sulcus vocalis is the presence of a groove extending along the vibratory surface of a vocal fold and may result in dysphonia. Depending on the level of severity, this condition may require treatment involving complicated surgical techniques. Cases of sulcus vocalis are classified as physiological, vergeture, or pouch type. A clear explanation of the etiology has not been established, and the currently proposed congenital origin, as described in the literature, remains controversial. This paper presents findings from monozygotic twin sisters with bilateral sulcus vocalis; these patients had similar morphologies, vibratory characteristics, and vocal quality measurements, which support the theory of a congenital etiology.