SYNE1 gene mutation: A recessive ataxic syndrome presenting with weakness and muscle atrophy. A case report

•SCAR8 is a rare neurodegenerative pathology resulting from a SINE1 gene mutation.•Autosomal recessive disease, with 11 cases reported in Latin America.•Motoneuron disease spectrum is a confounding factor in identifying this rare condition. Autosomal recessive spinocerebellar ataxia type 8 (SCAR8) is a rare neurodegenerative disease that can be manifest in a wide spectrum from ataxias and motoneuron syndromes. To report a case of mutation in the SYNE1 gene with predominant motoneuron disease signs. Index case medical report and literature review. A 32-year-old woman onset with pyramidal and lower motoneuron signs and symptoms during the second decade of life, with marked dysarthria showing associated cerebellar pattern. Clinical investigation with electroneuromyography showed chronic preganglionic disease and brain MRI showed cerebellar atrophy. Genetic testing confirmed pathogenic mutation in homozygosity in the SYNE1 gene. Rare neurological condition that may be associated with signs of impairment of the pyramidal pathway and second motoneuron (amyotrophic lateral sclerosis-like syndrome), in addition to cerebellar ataxia in insidious course.