Novel SLC18A2 variant in infantile dystonia parkinsonism type 2: a case report

Abstract

Background: Infantile dystonia parkinsonism type 2 (PKDYS2) is a rare inherited autosomal recessive movement disorder with onset in infancy. The disease is associated with a mutation in the solute carrier family 18 member A2 gene (SLC18A2). There are reports of trials with dopaminergic drugs, mainly levodopa and dopamine agonists, and the condition of patients given levodopa almost always worsens and dopamine agonists give varying degrees of benefit to some. Here, we report the first PKDYS2 patient in Finland who underwent multiple trials of pharmacotherapy. Case report: The abnormalities in development and neurological examination were first noted at the age of 2 months, and after a series of treatment attempts (e.g. with antiepileptics) and diagnostic procedures, the diagnosis of PKDYS2 was finally determined when whole exome sequencing (WES) at age 6, revealed a homozygous pathologic variant NM_003054.4:c.1107dup, p.(Val370Serfs*91) in the SLC18A2 gene. After the correct diagnosis was confirmed, the patient received treatment with dopaminergic drugs (e.g. levodopa, pramipexole, methylphenidate). Conclusions: We report a patient with PKDYS2 harboring a new variant in SLC18A2. The phenotype of the patient resembles that of some previously reported patients with PKDYS2. The patient received minor benefit from certain drugs, such as pramipexole, but prominent side effects led to the discontinuation of all tested medications.