AUTHOR=Liu De-Tian , Tang Xue-Qing , Wan Rui-Ping , Luo Sheng , Guan Bao-Zhu , Li Bin , Liu Li-Hong , Li Bing-Mei , Liu Zhi-Gang , Xie Long-Shan , Yi Yong-Hong 

TITLE=PRRT2 gene mutations associated with infantile convulsions induced by sucking and the genotype-phenotype correlation

JOURNAL=Frontiers in Neurology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.836048

DOI=10.3389/fneur.2022.836048

ISSN=1664-2295

ABSTRACT=<sec><title>Introduction</title><p><italic>PRRT2</italic> is a major causative gene for self-limited familial neonatal-infantile epilepsy, paroxysmal kinesigenic dyskinesia, and paroxysmal kinesigenic dyskinesia with infantile convulsions. Voluntary movement trigger is prominent in adolescence and adulthood, but the triggers are unknown in infants.</p></sec><sec><title>Methods</title><p>A gene panel designed for targeted next-generation sequencing (NGS) was used to screen genetic abnormalities in a cohort of 45 cases with infantile convulsions. The copy number variation was detected by a computational method based on the normalized depth of coverage and validated by a quantitative real-time polymerase chain reaction (RT-qPCR) method. The genotype-phenotype correlation of the <italic>PRRT2</italic> mutation gene was analyzed.</p></sec><sec><title>Results</title><p>A <italic>de novo</italic> heterozygous <italic>PRRT2</italic> deletion was identified in a child who had infantile convulsions induced by vigorous sucking. Seizures happened during the change of feeding behavior from breast to formula, which led to hungry and vigorous sucking. Ictal electroencephalograms recorded seizures with focal origination, which provided direct evidence of epileptic seizures in infants with <italic>PRRT2</italic> mutations. Seizures stopped soon after the feeding behavior was changed by reducing feeding interval time and extending feeding duration. Data reanalysis on our previously reported cases with <italic>PRRT2</italic> mutations showed that six of 18 (33.3%) patients had infantile convulsions or infantile non-convulsion seizures during feeding. The mutations included two truncating mutations (c.579dupA/p.Glu194Argfs<sup>*</sup>6, and c.649dupC/p.Arg217Profs<sup>*</sup>8) that were identified in each of the three affected individuals.</p></sec><sec><title>Conclusions</title><p>This study suggests that feeding, especially vigorous sucking, is potentially a trigger and highlights the significance of feeding behavior in preventing seizures in infants with <italic>PRRT2</italic> mutations. Identification of <italic>PRRT2</italic> haploinsufficiency mutations in the patients with infantile convulsions induced by sucking suggested a potential genotype-phenotype correlation.</p></sec>