AXH is a protein-protein and RNA binding motif found in Ataxin-1 (ATX1). ATX1 is responsible for the autosomal-dominant neurodegenerative disorder Spinocerebellar ataxia type-1 (SCA1) in humans. The AXH module has also been identified in the apparently unrelated transcription factor HBP1 which is thought to be involved in the architectural regulation of chromatin and in specific gene expression .
Spinocerebellar ataxia type 1 is late-onset neurodegenerative diseases caused by the expansion of a CAG triplet repeat in the SCA1 gene. This results in the lengthening of a polyglutamine tract in the gene product ataxin-1 producing a toxic gain of function that results in neuronal death.