Neurodevelopmental trajectory and modifiers of 16p11.2 microdeletion: A follow-up study of four Chinese children carriers
MOLECULAR GENETICS & GENOMIC MEDICINE
Authors: Xie, Hua; Liu, Fang; Zhang, Yu; Chen, Qian; Shangguan, Shaofang; Gao, Zhijie; Wu, Nan; Wang, Jian; Cui, Xiaodai; Wang, Lin; Chen, Xiaoli
Abstract
Background: Neurodevelopmental disorders (NDDs) are a group of disorders with high genetic and phenotypic heterogeneities. The 16p11.2 microdeletion has been implicated as an important genetic risk factor for NDDs. Methods: Multiple genetic tests were used to detect the 16p11.2 microdeletion from 918 Chinese children with NDDs. Targeted sequencing of genes in the 16p11.2 interval was performed in all carriers of the 16p11.2 microdeletion, and whole-genome expression profiling analysis was performed for the patient carriers and normal carriers in their intra-family. Results: Three patients carrying the 16p11.2 microdeletion were screened out, indicating a frequency of 0.33% for the 16p11.2 microdeletion in this cohort. We reviewed the neurodevelopmental trajectories of the 16p11.2 microdeletion carriers from childhood to puberty and confirmed that this microdeletion was associated with abnormal neurodevelopment, with varied neurodevelopmental phenotypes. A differentialPRRT2genotype (rs10204, T>C) was identified between patients and normal carriers of the 16p11.2 microdeletion. Moreover, the determination of differential whole-genome expression profiling demonstrated the destruction of the top-ranked network in neurogenesis and accounted for observation of abnormal neurodevelopmental phenotypes in the 16p11.2 microdeletion carriers. Conclusions: We have provided the frequency of the 16p11.2 microdeletion in a Chinese pediatric NDD cohort with a variable NDD phenotype from childhood to puberty, which is useful for Chinese geneticists/pediatricians to conduct the 16p11.2 microdeletion testing in children with NDDs.
PRRT2 Regulates Synaptic Fusion by Directly Modulating SNARE Complex Assembly
CELL REPORTS
Authors: Coleman, Jeff; Jouannot, Ouardane; Ramakrishnan, Sathish K.; Zanetti, Maria N.; Wang, Jing; Salpietro, Vincenzo; Houlden, Henry; Rothman, James E.; Krishnakumar, Shyam S.
Abstract
Mutations in proline-rich transmembrane protein 2 (PRRT2) are associated with a range of paroxysmal neurological disorders. PRRT2 predominantly localizes to the pre-synaptic terminals and is believed to regulate neurotransmitter release. However, the mechanism of action is unclear. Here, we use reconstituted single vesicle and bulk fusion assays, combined with live cell imaging of single exocytotic events in PC12 cells and biophysical analysis, to delineate the physiological role of PRRT2. We report that PRRT2 selectively blocks the trans SNARE complex assembly and thus negatively regulates synaptic vesicle priming. This inhibition is actualized via weak interactions of the N-terminal proline-rich domain with the synaptic SNARE proteins. Furthermore, we demonstrate that paroxysmal dyskinesia-associated mutations in PRRT2 disrupt this SNARE-modulatory function and with efficiencies corresponding to the severity of the disease phenotype. Our findings provide insights into the molecular mechanisms through which loss-of-function mutations in PRRT2 result in paroxysmal neurological disorders.