Genetic aetiology of global developmental delay and intellectual disability in Africa: a scoping review

Background: The genetic aetiology of global developmental delay (GDD) and intellectual disability (ID) in Africa is poorly understood. This review synthesises the available information on this topic. Methods: Original articles published in the English language between January 2000 and June 2024 on the African population were included. Literature was retrieved from PubMed, Scopus, and Web of Science, in accordance with the PRISMA guidelines. Results: Of all the 54 African countries, only 13 reported the genetic factors associated with GDD and ID. The genes related to GDD and ID were reported in Egypt (22), Tunisia (17), Morocco (16), South Africa (10), Algeria (4), Sudan (3), Libya (2), Nigeria (2), Rwanda (4), Mali (1), Cameroon (1), DRC (2), and Tanzania (1), although some genes were reported in more than one African country. At least 45 genes associated with GDD and ID have been reported in the African population, whereas 21 genes associated with these disorders are yet to be documented in Africa. Conclusion: This review provides, to the best of our knowledge, the first comprehensive review of the genetic aetiology of GDD and ID in Africa. It presents an imbalance of gene research on GDD and ID across African regions, with North African countries dominating this field of study.