The genetic elucidation of monogenic obesity in the Arab world: a systematic review

Background Investigation of monogenic obesity (MO), a rare condition caused by a single gene variant(s), especially in consanguineous populations, is a powerful approach for obtaining novel insights into the genetic alterations involved. Here, we present a systematic review of the genetics of MO in the 22 Arab countries and apply protein modeling in silico to the missense variants reported. Methods We searched four literature databases (PubMed, Web of Science, Science Direct and Scopus) from the time of their first creation until December 2020, utilizing broad search terms to capture all genetic studies related to MO in the Arab countries. Only articles published in peer-reviewed journals involving subjects from at least one of the 22 Arab countries and dealing with genetic variants related to MO were included. Protein modelling of the variants identified was performed using PyMOL. Results The 30 cases with severe early-onset obesity identified in 13 studies carried 14 variants in five genes ( LEP, LEPR, POMC, MC4R and CPE ). All of these variants were pathogenic, homozygous and carried by members of consanguineous families. Conclusion Despite the elevated presence of consanguinity in the Arab countries, the genetic origins of MO remain largely unexplained and require additional studies, both of a genetic and functional character.