One case of acute encephalopathy associated with 16p11.2 deletion and PRRT2 gene mutation

BACKGROUND: PRRT2 is associated with autosomal dominant paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile epilepsy (BFIE) and other diseases. OBJECTIVE: To explore the phenotypic spectrum associated with PRRT2 mutations, we analyzed a patient carrying a 16p11.2 deletion including PRRT2. METHODS: A retrospective analysis was conducted on the clinical and genetic characteristics of a patient with a 16p11.2 deletion containing PRRT2. A literature search was performed in CNKI, Wanfang, and PubMed from the establishment of the databases to December 2025, using the keywords "acute encephalopathy", "PRRT2", "paroxysmal non-kinesigenic dyskinesia", "ataxia", "copy number variation of chromosome 16", and "16p11.2 deletion", to identify case reports similar to the present case. RESULT: This patient presented with infection-induced acute encephalopathy, acute-onset non-motor-induced movement disorders and ataxia phenotype. Genetic testing indicated a 16p11.2 deletion involving PRRT2, de novo. After immunotherapy and rehabilitation treatment, the patient achieved a favorable prognosis. Literature review identified only two complete international case reports similar to this case (specifically regarding ataxia), and genetic analysis showed that they were respectively a 16p11.2 deletion containing PRRT2 and a PRRT2 gene variation. CONCLUSION: The 16p11.2 deletion containing PRRT2 has been reported for the first time to present as an acute encephalopathy phenotype. Rare cases of paroxysmal non-motor-induced movement disorder (PNKD) and ataxia have also been reported. These findings underscore the importance of timely genetic testing and appropriate genetic counseling for patients presenting with unexplained acute encephalopathy and/or acute episodic non-motor-induced movement disorders, as well as those with ataxia symptoms.