Introduction:
Spinocerebellar ataxias (SCAs) denote a heterogeneous group of hereditary neurodegenerative disorders, most commonly presenting in adulthood. Nevertheless, few entities have their onset in childhood, including SCA type 29 (SCA29). It is associated with dominant pathogenic variants in the ITPR1 gene, which encodes a calcium channel essential for Purkinje cell function. Clinically, SCA29 is characterized by early-onset cerebellar ataxia, global motor delay, and infantile muscular hypotonia.

Aim:
The aim of this case report is to present detailed clinical and therapeutic management of an individual affected with SCA29.

Material and methods:
The patient is a 5-year-old boy born at term after an uneventful pregnancy. From infancy, he exhibited hypotonia, delayed attainment of milestones, and reduced responsiveness to visual stimuli. Since the age of 4 years, he has been walking only with bilateral support. The patient’s cognitive development is normal, speech is inadequate for the age, dysarthric. Magnetic resonance imaging revealed cerebellar hypoplasia, a significant feature of SCA29. Trio-based whole exome sequencing identified a pathogenic heterozygous missense variant in the ITPR1 gene: c.722G>A p.(Arg241Lys). The variant was absent from both parents, confirming its de novo character. Genetic testing combined with clinical findings led to a diagnosis of SCA29.

Conclusions:
SCA29 is an ultra-rare disorder, which clinical manifestation overlaps with various other neurological entities, posing difficulties in differential diagnosis. Genetic analysis should be considered in any child exhibiting signs of ataxia of unknown etiology. Early diagnosis is of particular importance, as timely implemented interprofessional rehabilitation may enhance the children’s development and facilitate access to patient support groups.