<prompt> Defect seen in Vitiligo is: September 2010Absent melanosomesAbsent melanocytesReduction in melanin synthesisReduction in number of melanocytes  <response>: Ans. B: Absent melanocytes Vitiligo is a chronic disorder that causes depigmentation of patches of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. 