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The distribution of neural crest cells is briefly reviewed. The behaviour of neural crest derivatives in Africans is different from that seen in Caucasians, both in terms of physiology and pathology. The most obvious variation is in the depth of pigmentation of the skin, but most diseases of neural crest derived tissues show differences between Black and White subjects. The reason for these differences are not readily apparent but appear to be of genetic rather than environmental origin.

A case of Crohn's disease occurring in a Kenyan African is described. Review of literature disclosed 14 acceptable cases occurring in African subjects. The symptoms, anatomical distribution, signs, and pathology in black patients in Africa and America are similar to that described in whites. The disease is probably underdiagnosed in Africa because of difficulties in distinguishing schistosomiasis and tuberculosis of the bowel.