Spectrum of genetic variants associated with maple syrup urine disease in the Middle East, North Africa, and Türkiye (MENAT): a systematic review

Abstract

Background Maple syrup urine disease (MSUD) is a hereditary metabolic disorder caused by a deficiency in the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. The Middle East and North Africa, and Türkiye (MENAT) region has witnessed a significant rise in the prevalence of MSUD due to high rates of consanguinity. Despite numerous genetic association studies, the complex relationships between genotype and phenotype in MSUD remain elusive.

Aim This study aimed to systematically review the variants significantly associated with MSUD in the MENAT region.

Methods We systematically searched four literature databases (PubMed, Scopus, Web of Science, and Science Direct) from inception until December 2023 to gather all reported genetic data pertaining to MSUD in the MENAT region. Quality assessment and data extraction were diligently performed by a team of six investigators.

Results A total of 16 studies, involving patients, were included in this systematic review. Among them, 211 patients presented with 105 variants located within genes known to be associated with MSUD. The majority of the identified MSUD variants were found in BCKDHA (38%), followed by BCKDHB (38%), DBT (23%), and PPM1K (1%). Notably, 77% of the captured variants were unique to the MENAT region.

Conclusion Our systematic review reveals a distinctive genetic and clinical susceptibility profile of MSUD among individuals from the MENAT region. These findings highlight the importance of understanding the specific genetic landscape of MSUD in this population. Further research is warranted to elucidate the complex genotype-phenotype relationships in MSUD in the MENAT region.