Pathogenic variants in ATP8A2 can cause different congenital disorders (i.e. conditions that are present from birth) characterized by lack of voluntary coordination of muscle movements (ataxia) and other clinical features. The most consensually established disorder caused by pathogenic variants in the ATP8A2 gene is cerebellar ataxia, mental retardation and disequilibrium (CAMRQ) type 4. Diagnosis of CAMRQ is made based on the patients’ symptoms, a positive or negative family history, and the presence of a pathogenic mutation in ATP8A2 gene. CAMRQ can be inherited when each parent carry one copy of the altered gene and transmitted to the child (autosomal recessive manner). It is a rare disease, affecting <1 per 1.000.000 people.