Identification of a putative founder variant in SLC30A10 associated with hypermanganesemia with dystonia 1 in Iranian patients: a case series and literature review

Hypermanganesemia with dystonia 1 (HMNDYT1) is an rare autosomal recessive condition resulting from pathogenic variants in the SLC30A10 gene. The presence of biallelic variants in this gene results in systemic accumulation of manganese, which leads to dystonia, polycythemia, and liver dysfunction. We conducted clinical and genetic evaluations of seven affected individuals from six Iranian consanguineous families, emphasizing the identification of potential founder mutations, and integrated this information with a total of 80 previously reported cases. Analysis of exome sequencing in all seven individuals affected revealed the presence of the identical homozygous variant in SLC30A10 (c.1006 C > T; p.His336Tyr), suggesting a potential founder effect. The estimated most recent common ancestor for these patients lived approximately 47 generations ago, suggesting an ancient mutation originating from a common ancestor. A literature review of 80 reported HMNDYT1 cases demonstrated that hypermanganesemia, T1 hyperintensity of the basal ganglia and dentate nuclei, dystonia, and polycythemia constitute the predominant clinical features. Symptom onset occurred primarily within the first five years of life (median: ~2 years, range: 0.25–57 years). Collectively, these observations underscore the need to identify potential founder variants and to more comprehensively characterize the genotypic and phenotypic spectrum of SLC30A10 to inform genetic counseling and population-based screening strategies.