Autosomal recessive spinocerebellar ataxia 13 (SCAR13; MIM 614831) is an ultra-rare disorder caused by pathogenic or disruptive mutations in the GRM1 gene, located on chromosome 6q24.3 [31]. This evidence concerns the gene GRM1 and Autosomal recessive congenital cerebellar ataxia due to MGLUR1 deficiency.