Background: Myotonic dystrophy type 2 (DM2) is a multisystem disorder, mostly presented with mild but heterogeneous spectrum of symptoms. Objective: The aim of this research was to provide detailed sociodemographic, clinical and laboratory data of a

Leber’s hereditary optic neuropathy (LHON) is a maternally inherited disorder that affects central vision in young adults and is typically associated with mitochondrial DNA (mtDNA) mutations. This study is based on a mutational screening of entire mtDNA in eight Serbian probands clinically and genetically diagnosed with LHON and four of their family members, who are asymptomatic mutation carriers. All obtained sequence variants were compared to human mtDNA databases, and their potential pathogenic characteristics were assessed by bioinformatics tools. Mitochondrial haplogroup analysis was performed by MITOMASTER. Our study revealed two well-known primary LHON mutations, m.11778G>A and m.3460G>A, and one rare LHON mutation, m.8836A>G. Various secondary mutations were detected in association with the primary mutations. MITOMASTER analysis showed that the two well-known primary mutations belong to the R haplogroup, while the rare LHON m.8836A>G was detected within the N1b haplogroup. Our results support the need for further studies of genetic background and its role in the penetrance and severity of LHON.