[Clinical manifestations and genetic diagnosis of paroxysmal kinesigenic dyskinesia]

The clinical manifestations of five children with paroxysmal kinesigenic dyskinesia (PKD) were retrospectively analyzed and their gene mutations were analyzed by high-throughput sequencing and chromosome microarray. The 5 patients consisted of 4 males and 1 female and the age of onset was 6-9 years. Dyskinesia was induced by sudden turn movement, scare, mental stress, or other factors. These patients were conscious and had abnormal posture of unilateral or bilateral extremities, athetosis, facial muscle twitching, and abnormal body posture. The frequency of onset ranged from 3-5 times a month to 2-7 times a day, with a duration of <30 seconds every time. Electroencephalography showed no abnormality in these patients. Three patients had a family history of similar disease. The high-throughput sequencing results showed that a heterozygous mutation in the PRRT2 gene, c.649_650insC (p.R217PfsX8), was found in two patients; the mutation c.436C>T (p.P146S) was found in one patient; a splice site mutation, IVS2-1G>A, was found in one patient. The two mutations c.436C>T and IVS2-1G>A had not been reported previously. The chromosome microarray analysis was performed in one patient with negative results of gene detection, and the chromosome 16p11.2 deletion (0.55 Mb) was observed. Low-dose carbamazepine was effective for treatment of the 5 patients. PKD is a rare neurological disease. The detection of the PRRT2 gene by multiple genetic analysis can help the early diagnosis of PKD.