A CAPOS syndrome patient presenting a good clinical course regarding recurrent acute encephalopathy and acute cerebellar ataxia attacks after acetazolamide treatment

Abstract

  CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing loss) syndrome is an ATP1A3-related disorder caused by a heterozygous mutation (c.2452G>A) of the ATP1A3 gene. We herein report a male patient with CAPOS syndrome who presented disturbance of consciousness, ataxia, muscular hypotonia and areflexia associated with febrile illness three times during his early childhood. He was suspected of having CAPOS syndrome because of sensorineural hearing loss and an optic nerve disorder found by a detailed examination, although pes cavus was absent. Sanger sequencing revealed a de novo heterozygous mutation (NM_152296.5 : c.2452G>A [p.Glu818Lys]) in exon 18 of the ATP1A3 gene. After acetazolamide treatment was initiated, the patient did not experience any acute episodes for 2 years and 5 months. A detailed family history evaluation, an ophthalmologic work-up, a hearing examination and genetic testing are recommended for patients with repetitive acute encephalopathy, acute cerebellar ataxia or Guillain-Barré syndrome-like episodes.