Racial and Ethnic Concentration of Genetic Disorders
Most genetic diseases occur without regard for the affected individual’s racial or ethnic background. Some, however, are concentrated in certain population groups and may reflect a previous advantage of the mutation (particularly in the carrier state). For example, sickle cell carriers are more resistant to malaria and the disease is common in African-derived populations.
Tay-Sachs disease (GM2 gangliosidosis type I), with its characteristic macular cherryred spot, occurs predominantly in persons of Eastern European Jewish (Ashkenazic) ancestry. An estimated rate of 1 in 30 for carriers of this disorder in the Jewish population of New York City compares with an estimated carrier rate of 1 in 300 in non-Jewish Americans. Familial dysautonomia (Riley-Day syndrome)—characterized by alacrima, corneal hypoesthesia, exodeviation, and methacholine-induced miosis—also occurs more frequently in persons of Ashkenazic ancestry, as do MAK (male germ cell–associated kinase)-associated RP, Gaucher disease, and Niemann-Pick disease.
Several types of achromatopsia (complete color blindness) with myopia are common on the South Pacific island of Pingelap, affecting 5% of the Pingelapese population in the Caroline Islands of Micronesia. Oguchi disease is observed primarily, though not exclusively, in Japanese people. Similarly, sickle cell hemoglobinopathies are inherited largely among African Americans.
The prevalence of oculocutaneous albinism is high among the Kuna Indians in Panama. Hermansky-Pudlak syndrome (HPS) occurs with a higher frequency in persons of Puerto Rican ancestry. HPS is an autosomal recessive disorder characterized by oculocutaneous albinism, pulmonary interstitial fibrosis, easy bruising, and bleeding tendency, associated with a prolonged bleeding time and abnormal platelet aggregation.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.