ATP1A3 mosaicism in families with alternating hemiplegia of childhood.

Alternating hemiplegia of childhood (AHC) is a rare and severe neurodevelopmental disorder characterized by recurrent hemiplegic episodes. Most AHC cases are sporadic and caused by de novo ATP1A3 pathogenic variants. In this study, the aim was to identify the origin of ATP1A3 pathogenic variants in a Chinese cohort. In 105 probands including 101 sporadic and 4 familial cases, 98 patients with ATP1A3 pathogenic variants were identified, and 96.8% were confirmed as de novo. Micro-droplet digital polymerase chain reaction was applied for detecting ATP1A3 mosaicism in 80 available families. In blood samples, four asymptomatic parents, including two paternal and two maternal, and one proband with a milder phenotype were identified as mosaicism. Six (7.5%) parental mosaicisms were identified in multiple tissues, including four previously identified in blood and two additional cases identified from paternal sperms. Mosaicism was identified in multiple tissues with varied mutant allele fractions (MAFs, 0.03%-33.03%). The results suggested that MAF of mosaicism may be related to phenotype severity. This is the first systematic report of ATP1A3 mosaicism in AHC and showed mosaicism as an unrecognized source of previously considered "de novo" AHC. Identifying ATP1A3 mosaicism provides more evidence for estimating recurrence risk and has implications in genetic counseling of AHC.

Profiling the RNA editomes of wild-type C. elegans and ADAR mutants.

RNA editing increases transcriptome diversity through post-transcriptional modifications of RNA. Adenosine deaminases that act on RNA (ADARs) catalyze the adenosine-to-inosine (A-to-I) conversion, the most common type of RNA editing in higher eukaryotes. Caenorhabditis elegans has two ADARs, ADR-1 and ADR-2, but their functions remain unclear. Here, we profiled the RNA editomes of C. elegans at different developmental stages of wild-type and ADAR mutants. We developed a new computational pipeline with a "bisulfite-seq-mapping-like" step and achieved a threefold increase in identification sensitivity. A total of 99.5% of the 47,660 A-to-I editing sites were found in clusters. Of the 3080 editing clusters, 65.7% overlapped with DNA transposons in noncoding regions and 73.7% could form hairpin structures. The numbers of editing sites and clusters were highest at the L1 and embryonic stages. The editing frequency of a cluster positively correlated with the number of editing sites within it. Intriguingly, for 80% of the clusters with 10 or more editing sites, almost all expressed transcripts were edited. Deletion of adr-1 reduced the editing frequency but not the number of editing clusters, whereas deletion of adr-2 nearly abolished RNA editing, indicating a modulating role of ADR-1 and an essential role of ADR-2 in A-to-I editing. Quantitative proteomics analysis showed that adr-2 mutant worms altered the abundance of proteins involved in aging and lifespan regulation. Consistent with this finding, we observed that worms lacking RNA editing were short-lived. Taken together, our results reveal a sophisticated landscape of RNA editing and distinct modes of action of different ADARs.

Identifying "hot papers" and papers with "delayed recognition" in large-scale datasets by using dynamically normalized citation impact scores.

"Hot papers" (HPs) are papers which received a boost of citations shortly after publication. Papers with "delayed recognition" (DRs) received scarcely impact over a long time period, before a considerable citation boost started. DRs have attracted a lot of attention in scientometrics and beyond. Based on a comprehensive dataset with more than 5,000,000 papers published between 1980 and 1990, we identified HPs and DRs. In contrast to many other studies on DRs, which are based on raw citation counts, we calculated dynamically field-normalized impact scores for the search of HPs and DRs. This study is intended to investigate the differences between HPs (n = 323) and DRs (n = 315). The investigation of the journals which have published HPs and DRs revealed that some journals (e.g. Physical Review Letters and PNAS) were able to publish significantly more HPs than other journals. This pattern did not appear in DRs. Many HPs and DRs have been published by authors from the USA; however, in contrast to other countries, authors from the USA have published statistically significantly more HPs than DRs. Whereas "Biochemistry & Molecular Biology," "Immunology," and "Cell Biology" have published significantly more HPs than DRs, the opposite result arrived for "Surgery" and "Orthopedics." The results of the analysis of certain properties of HPs and DRs (e.g. number of pages) suggest that the emergence of DRs is an unpredictable process.

Sequence analysis of annually normalized citation counts: an empirical analysis based on the characteristic scores and scales (CSS) method.

In bibliometrics, only a few publications have focused on the citation histories of publications, where the citations for each citing year are assessed. In this study, therefore, annual categories of field- and time-normalized citation scores (based on the characteristic scores and scales method: 0 = poorly cited, 1 = fairly cited, 2 = remarkably cited, and 3 = outstandingly cited) are used to study the citation histories of papers. As our dataset, we used all articles published in 2000 and their annual citation scores until 2015. We generated annual sequences of citation scores (e.g., [Formula: see text]) and compared the sequences of annual citation scores of six broader fields (natural sciences, engineering and technology, medical and health sciences, agricultural sciences, social sciences, and humanities). In agreement with previous studies, our results demonstrate that sequences with poorly cited (0) and fairly cited (1) elements dominate the publication set; sequences with remarkably cited (3) and outstandingly cited (4) periods are rare. The highest percentages of constantly poorly cited papers can be found in the social sciences; the lowest percentages are in the agricultural sciences and humanities. The largest group of papers with remarkably cited (3) and/or outstandingly cited (4) periods shows an increasing impact over the citing years with the following orders of sequences: [Formula: see text] (6.01%), which is followed by [Formula: see text] (1.62%). Only 0.11% of the papers (n = 909) are constantly on the outstandingly cited level.

Human transporter database: comprehensive knowledge and discovery tools in the human transporter genes.

Transporters are essential in homeostatic exchange of endogenous and exogenous substances at the systematic, organic, cellular, and subcellular levels. Gene mutations of transporters are often related to pharmacogenetics traits. Recent developments in high throughput technologies on genomics, transcriptomics and proteomics allow in depth studies of transporter genes in normal cellular processes and diverse disease conditions. The flood of high throughput data have resulted in urgent need for an updated knowledgebase with curated, organized, and annotated human transporters in an easily accessible way. Using a pipeline with the combination of automated keywords query, sequence similarity search and manual curation on transporters, we collected 1,555 human non-redundant transporter genes to develop the Human Transporter Database (HTD) (http://htd.cbi.pku.edu.cn). Based on the extensive annotations, global properties of the transporter genes were illustrated, such as expression patterns and polymorphisms in relationships with their ligands. We noted that the human transporters were enriched in many fundamental biological processes such as oxidative phosphorylation and cardiac muscle contraction, and significantly associated with Mendelian and complex diseases such as epilepsy and sudden infant death syndrome. Overall, HTD provides a well-organized interface to facilitate research communities to search detailed molecular and genetic information of transporters for development of personalized medicine.

Postzygotic single-nucleotide mosaicisms in whole-genome sequences of clinically unremarkable individuals.

Postzygotic single-nucleotide mutations (pSNMs) have been studied in cancer and a few other overgrowth human disorders at whole-genome scale and found to play critical roles. However, in clinically unremarkable individuals, pSNMs have never been identified at whole-genome scale largely due to technical difficulties and lack of matched control tissue samples, and thus the genome-wide characteristics of pSNMs remain unknown. We developed a new Bayesian-based mosaic genotyper and a series of effective error filters, using which we were able to identify 17 SNM sites from ~80× whole-genome sequencing of peripheral blood DNAs from three clinically unremarkable adults. The pSNMs were thoroughly validated using pyrosequencing, Sanger sequencing of individual cloned fragments, and multiplex ligation-dependent probe amplification. The mutant allele fraction ranged from 5%-31%. We found that C→T and C→A were the predominant types of postzygotic mutations, similar to the somatic mutation profile in tumor tissues. Simulation data showed that the overall mutation rate was an order of magnitude lower than that in cancer. We detected varied allele fractions of the pSNMs among multiple samples obtained from the same individuals, including blood, saliva, hair follicle, buccal mucosa, urine, and semen samples, indicating that pSNMs could affect multiple sources of somatic cells as well as germ cells. Two of the adults have children who were diagnosed with Dravet syndrome. We identified two non-synonymous pSNMs in SCN1A, a causal gene for Dravet syndrome, from these two unrelated adults and found that the mutant alleles were transmitted to their children, highlighting the clinical importance of detecting pSNMs in genetic counseling.

De novo insertions and deletions of predominantly paternal origin are associated with autism spectrum disorder.

Whole-exome sequencing (WES) studies have demonstrated the contribution of de novo loss-of-function single-nucleotide variants (SNVs) to autism spectrum disorder (ASD). However, challenges in the reliable detection of de novo insertions and deletions (indels) have limited inclusion of these variants in prior analyses. By applying a robust indel detection method to WES data from 787 ASD families (2,963 individuals), we demonstrate that de novo frameshift indels contribute to ASD risk (OR = 1.6; 95% CI = 1.0-2.7; p = 0.03), are more common in female probands (p = 0.02), are enriched among genes encoding FMRP targets (p = 6 × 10(-9)), and arise predominantly on the paternal chromosome (p < 0.001). On the basis of mutation rates in probands versus unaffected siblings, we conclude that de novo frameshift indels contribute to risk in approximately 3% of individuals with ASD. Finally, by observing clustering of mutations in unrelated probands, we uncover two ASD-associated genes: KMT2E (MLL5), a chromatin regulator, and RIMS1, a regulator of synaptic vesicle release.

A guide RNA sequence design platform for the CRISPR/Cas9 system for model organism genomes.

Cas9/CRISPR has been reported to efficiently induce targeted gene disruption and homologous recombination in both prokaryotic and eukaryotic cells. Thus, we developed a Guide RNA Sequence Design Platform for the Cas9/CRISPR silencing system for model organisms. The platform is easy to use for gRNA design with input query sequences. It finds potential targets by PAM and ranks them according to factors including uniqueness, SNP, RNA secondary structure, and AT content. The platform allows users to upload and share their experimental results. In addition, most guide RNA sequences from published papers have been put into our database.

Recent adaptive events in human brain revealed by meta-analysis of positively selected genes.

BACKGROUND AND OBJECTIVES: Analysis of positively-selected genes can help us understand how human evolved, especially the evolution of highly developed cognitive functions. However, previous works have reached conflicting conclusions regarding whether human neuronal genes are over-represented among genes under positive selection. METHODS AND RESULTS: We divided positively-selected genes into four groups according to the identification approaches, compiling a comprehensive list from 27 previous studies. We showed that genes that are highly expressed in the central nervous system are enriched in recent positive selection events in human history identified by intra-species genomic scan, especially in brain regions related to cognitive functions. This pattern holds when different datasets, parameters and analysis pipelines were used. Functional category enrichment analysis supported these findings, showing that synapse-related functions are enriched in genes under recent positive selection. In contrast, immune-related functions, for instance, are enriched in genes under ancient positive selection revealed by inter-species coding region comparison. We further demonstrated that most of these patterns still hold even after controlling for genomic characteristics that might bias genome-wide identification of positively-selected genes including gene length, gene density, GC composition, and intensity of negative selection. CONCLUSION: Our rigorous analysis resolved previous conflicting conclusions and revealed recent adaptation of human brain functions.