Autosplenectomy occurs in:

b. Sickle cell anemia(Ref: Nelson's 20/e p 2336, Ghai 8/e p 345)Patients of sickle cell anemia may undergo auto-splenectomyQ due to multiple infarcts in splenic artery, that causes spleen to be reduced to fibrous tissue (splenic atrophy spleen may become non-palpable).