This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autoimmune skin disorders, Subject name: Dental
Melanocytes are reduced in number in all of the following Except 
Select and explain. 
A. Albinism, B. Vitiligo, C. Piebaldism, D. Chemical induced hypopigmentation
A: Albinism
Answer: A: Albinism 
Explanation: Albinism is a defect in the synthesis of melanin. Melanocytes are normally present and distributed Disorders of reduced melanin synthesis: albinism, Chediak-Higashi and Hermansky-Pudlack Reduced melanocytes is seen in vitiligo, piebaldism and Waardenburg syndrome Albinism. Albinism is a group of genetic disorders characterized by reduced or absent melanin pigmentation, with an overall estimated frequency of about 1 per 20000 in most populations (Ref: Harrison 20th edition pg 1234