Paroxysmal Kinesigenic Dyskinesia With Infantile Convulsions in a Child With Inherited Co-deletion of 16p11.2 and 16p12.2: A Case Report and Literature Review.

16p11.2 deletion syndrome is a group disorder associated with intellectual impairment, developmental delay, and autism spectrum disorder (ASD). Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) is an extremely rare condition. A 6-year-old Chinese boy presented with a two-month history of involuntary dystonic movements triggered by movement initiation (e.g., starting to walk, sudden activity after rest) or occurring spontaneously. He had a history of self-limiting infantile epilepsy from 6 months to 2 years of age. Notably, his father experienced benign infantile epilepsy during infancy (onset at 9 months, duration one year), and his grandparents were consanguineous. Based on clinical manifestations and whole-exome sequencing revealing biallelic inherited deletions, a 661.385 kb deletion at 16p11.2 (encompassing the PRRT2 gene) and a 760.266 kb deletion at 16p12.2 in the proband, with corresponding paternal deletions, the patient was diagnosed with PKD/IC. The patient received oral oxcarbazepine (OXC, 150 mg/day) to improve the symptoms. During follow-up after treatment initiation, his symptoms were well controlled, with no further PKD attacks. Early diagnosis of the disease is highly cost-effective and can help avoid unnecessary diagnostic and therapeutic interventions.