What are the racial predilections of hemoglobinopathy retinopathy?

Updated: Sep 03, 2019
  • Author: Brian A Phillpotts, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Answer

Although sickle cell disease first was described in a black patient, it is not confined to patients of African ancestry. Sickle cell trait is more common in Central Africa but is infrequent in North and South Africa.

Of people living in Northern Greece, 20-30% reportedly have Hb S.

Of Saudi Arabians, especially in the Qatif oasis, 25% have the variant gene.

Other locations where sickle cell disease occurs include Turkey, Southern Italy, the Mediterranean, and Central India (Orissa, Madhya Pradesh, and Maharastra).

Theories for this distribution include the protective mechanism of Hb S heterozygosity against falciparum malaria. The gene is most prevalent in Central Africa, particularly in regions where malaria is endemic. The gene is thought to persist because heterozygosity protects slightly against falciparum malaria. Parasitized sickle cell (Hb AS) erythrocytes have a shorter lifespan, so the parasite probably cannot complete its development. Furthermore, the growth of trophozoites is inhibited by low oxygen tension.


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