SCA15 is a cerebellar ataxia characterized by postural tremor, hyperreflexia, dysarthria and scanning speech, as well as gait, limb and truncal ataxia. Ocular anomalies include dysmetric saccades, impaired smooth pursuits and horizontal, gaze-evoked nystagmus. Affected individuals exhibit cerebellar atrophy mainly affecting the vermis. The disease has a wide range of onset, affecting people between the ages of 10 and 50 years. It has a very slow progression and most patients remain ambulatory. Even though there have been only around 80 reported cases of SCA15 worldwide, the condition has been noted as the most common non-trinucleotide repeat spinocerebellar ataxia in Central Europe.
SCA15 is diagnosed based on clinical features, neuroimaging studies and molecular analysis of the ITPR1 gene. While there is currently no cure for the condition, patients usually benefit from physical and occupational therapy. Affected individuals may also require ambulatory aids and treatment for osteoporosis. Prenatal testing and genetic counselling is available for affected families.