Instability walking is a fairly common complaint made by patients who come to be examined by a neurologist in polyclinics and hospitals. From a medical point of view, this symptom is included in the concept of "ataxia". Neurologists distinguish four types of ataxia depending on the localization of the pathological process: cortical, cerebellar, vestibular, and sensitive. There are often combinations of different types of ataxia in the same patient, for example, cortical-vestibular, sensitive-cerebellar. In addition to establishing the variant of the atactic syndrome, there is an urgent question of verifying the etiological factor that led to this pathology. Pathological heredity becomes the least obvious. In this article, we draw attention to a similar case from practice in order to form the alertness of doctors regarding hereditary coordination disorders. Episodic ataxia is a group of rare hereditary diseases of the nervous system, the main clinical manifestation of which are paroxysms of cerebellar ataxia of varying duration and frequency. The most studied from a genetic and clinical point of view are episodic cerebellar ataxia of the first and second types. The authors present a clinical case of episodic paroxysmal cerebellar ataxia type 2 in a 22-year-old patient. The diagnosis of the disease was based on a typical clinical picture and confirmed by a molecular genetic study that revealed a mutation in the CACNA1A gene. The article discusses aspects of the pathogenesis of the main forms of episodic paroxysmal ataxia, age of onset, frequency and duration of seizures, features of the clinical picture, neurological status. This clinical observation draws the attention of practitioners to the possibilities of modern methods of molecular genetic diagnosis and treatment of these conditions.