Praise be to Allah.
If it has become clear that the children of your husband’s brothers are afflicted by vitiligo – which is hereditary – and you are afraid of having children with the same problem, it is permissible for you to seek divorce, because this is a valid reason. The fuqaha’ have stated that one of the reasons that make it permissible to seek an annulment of the marriage is if the husband or wife has vitiligo that it is feared may be passed on to any offspring.
Ibn Qudaamah (may Allah have mercy on him) said in al-Mughni (7/185): Why these defects in particular are listed as valid reasons for annulment of the marriage is because they prevent enjoyment of intimacy, which is the purpose of marriage. Vitiligo and leprosy provoke revulsion and prevent one from coming near the afflicted person, and there is the fear that it may be contagious or may be passed on to any offspring, which is an impediment to intimacy. End quote.
Ahmad (22440), Abu Dawood (2226), at-Tirmidhi (1187) and Ibn Maajah (2055) narrated that Thawbaan (may Allah be pleased with him) said: The Messenger of Allah (blessings and peace of Allah be upon him) said:
“Any woman who asks her husband for divorce when there is no problem, the fragrance of Paradise will be forbidden to her.”
This hadith was classed as saheeh by Ibn Khuzaymah and Ibn Hibbaan, as was stated by al-Haafiz in al-Fath (9/403). It was also classed as saheeh by al-Albaani in Saheeh Abi Dawood, and by Shu‘ayb al-Arna’oot in Tahqeeq al-Musnad.
Psychological distress is included under the heading of the problems which make it permissible to seek divorce.
And Allah knows best.