Musannaf Ibn Abi Shayba 9:392

'Abdullah ibn Idris narrated to us, from Yahya ibn Sa'id, from Sa'id ibn al-Musayyib, from 'Umar, who said: "Whoever marries a woman and she has vitiligo, leprosy, or insanity, and he consummates the marriage with her, then she is entitled to the dowry because of what he made lawful of her private part, and that is a liability upon her guardian."