This is the first study of MG in Latvia and the second population-based study of MG in Eastern Europe. Our epidemiological results are similar to those in some other European and Northern American countries, and show high prevalence and increasing incidence of late-onset MG.

Background: Spinal and bulbar muscular atrophy (SBMA) or Kennedy disease [OMIM: 313200] is a rare X-linked neuromuscular disease. Patients commonly present with muscle cramps, tremors, leg weakness, dysarthria and dysphagia.Methods: We deeply phenotyped and evaluated the possible extent of affected systems in all patients with SBMA in Latvia (n = 5). In addition, neurophysiological studies and blood analyses were used to perform a molecular diagnosis and evaluate biochemical values. We analyzed neurofilament light (NfL) as a possible biomarker.Results: Neurological examination revealed typical SBMA clinical manifestations; all patients had small or large nerve fiber neuropathy. Three of five patients had increased neurofilament light levels.Conclusion: The study confirms the systemic involvement in patients suffering from SBMA. Increased NfL concentration was associated with either peripheral neuropathy or decreased body mass index. The complex phenotype of the disease should be kept in mind, as it could help to diagnose patients with SBMA.

Background: Kennedy disease or spinal and bulbar muscular atrophy (SBMA) is a rare X-linked neuromuscular disease. Patients commonly present with muscle cramps, tremor, leg weakness, dysarthria, and dysphagia. Methods: We deeply phenotyped and evaluated the possible extent of affected systems in all Kennedy disease patients in Latvia (n = 5), neurophysiological studies, blood analysis was used in order to carry out molecular diagnosis and evaluate biochemical values. We analysed neurofilament light as possible biomarker. Results: Neurological examination revealed typical manifestations of lower-motor neuron damage; two patients had polyneuropathy. Quantitative sensory testing revealed tactile threshold abnormalities and perception of mechanical pain in all patients. Three of five patients had increased neurofilament light levels. Conclusion: Study confirms the systemic involvement in patients suffering from Kennedy disease. Increased NfL concentration was associated with either peripheral neuropathy or decreased body mass index. The complex phenotype of the disease should be kept in mind as it could help to diagnose patients with SBMA.