Novel Genetic Variation in the KIF1A Gene Associated With Cerebellar Vermis Hypoplasia: A Case Report

<i>KIF1A</i>-associated neuronal disorder (KAND) is a spectrum of disease caused by a genetic mutation in the <i>KIF1A</i> gene. Genetic variants in this gene have been associated with cerebellar vermis hypoplasia, as well as mild to severe symptoms, including ataxia, motor and global developmental delay, and intention tremors. Given the limited number of reported cases, ample research is necessary to effectively manage this condition. A two-year-old girl presents with global developmental, motor, and speech delay, as well as jerky movements, possible athetosis, hand tremors, ataxia, vertical nystagmus, and muscle spasticity in lower limbs. She was referred to the clinic by her neurologist due to abnormal findings in her MRI, which showed cerebellar vermis hypoplasia. These results, together with her symptoms, suggested a genetic basis, for which a chromosomal microarray (CMA) was indicated. Results for the CMA showed two regions of homozygosity, prompting a whole-exome sequencing to be performed. This test revealed an autosomal dominant heterozygous missense mutation known as c.464G>C (p.R155P). Because there was no significant family history correlating with this disease, it appears that the mutation appeared de novo. The gene affected by this mutation is the <i>KIF1A</i> gene, which is located in 2q37.3. The <i>KIF1A</i> gene is responsible for encoding the kinesin-like protein KIF1A. This protein is responsible for microtubule motor function, as well as adenosine triphosphate (ATP) binding. Even though the mutation found in this patient was classified as a variant of uncertain significance, her severe symptoms suggest a pathological correlation. Her prognosis is reserved as there is no targeted treatment available. Due to the low incidence of this disease and the possibility of neurodegeneration in patients, more research is encouraged to develop effective disease management.