A rare neurodegenerative disorder mimicking autoimmune encephalitis induced by COVID-19: CONDSIAS

Introduction: Stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS) is an autosomal recessive disorder associated with a very rare childhood onset severe neurodegeneration syndrome with episodic, stress-induced seizures, ataxia, and axonal neuropathy. the ADP-Ribosylhydrolase Like 2(ADPRHL2) gene that encodes the protein reverses ADP-ribosylation is defected. In this study, we introduce a case of CONDSIAS with severe clinical presentation. Case: A three-year-old female patient, born to a nonconsanguineous family,was referred with various clinical symptoms including variable ataxia, torticollis, and gradual onset of truncal hypotonia in one year gradually. Magnetic resonance imagings(MRI) were done several and different period of times and found normal. She developed complete motor and speech regression, infrequent seizures, and loss of consciousness after three weeks of COVID-19 infection. Abnormal movements mostly myoclonic and choreiform types are seen.An electroencephalogram was performed and showed epileptic encephalopathy. Our patient developed a severe septicemia and had cardiac arrests several times. Neurodegenerative disorders and autoimmune encephalitis were in our differential diagnosis and intravenous immunoglobulin, neurotransmitter precursors were administered for these disorders. All basic metabolic tests and tests for autoimmune encephalitis were normal. A homozygous frameshift variant in the ADPRHL2 gene(NM_017825.3; c.529_530del,p.S177Gfs*48) was identified by whole-exome sequencing (WES).She is being followed up inpatient clinic and new MRI showed minimal cerebral,cerebellar atrophy. Conclusion:CONDSIAS is a neurodegenerative disorder which has broad phenotypic spectrum. In the present study, we introduced a female child with a variation in the ADPRHL2 gene presented with ataxia, abnormal movements, seizures and similar clinical course with autoimmune encephalitis induced by COVID-19.
Keywords: CONDSIAS, Covid-19, ataxia