RESUMEN
Alternating hemiplegia, a rare neurological disease that manifests in children under the age of 18 months, is characterized by transient episodes of hemiparesis of an alternating nature in the waking period. In addition to transient hemiparesis, neurological symptoms in the form of choreoathetosis, ataxia, dystonia, autonomic dysfunction, ocular apraxia, nystagmus, seizures, dysarthria and intellectual disorders may develop. Mutation in the ATP1A3 gene is the cause of the disease in more than 75% of patients. In some cases, the use of flunarizine, adenosine triphosphate and a ketogenic diet can reduce the frequency and duration of hemiplegic attacks. The authors report a case of a patient with alternating hemiplegia caused by a heterozygous mutation in exon 8 of the ATP1A3 gene (chr19: 42489098A>T, rs606231428), resulting in an amino acid substitution at position 335 (p.Val335Asp, NM_001256214.1). The use of flunarizin in a dose of 5 mg/day significantly reduces the number and duration of seizures, while oral adenosine-5-triphosphoric acid in a dose of 20 mg/kg/day is not effective.