Guy A. Rouleau

Bio: Guy A. Rouleau is an academic researcher from Montreal Neurological Institute and Hospital. The author has contributed to research in topics: Genome-wide association study & Amyotrophic lateral sclerosis. The author has an hindex of 129, co-authored 884 publications receiving 65892 citations. Previous affiliations of Guy A. Rouleau include Utrecht University & University of Helsinki.

TDP–43, Protein Aggregation, and Amyotrophic Lateral Sclerosis

Abstract: Clinical Features of Amyotrophic Lateral Sclerosis Amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease, is a neurological disorder characterized by the selective loss of upper and lower motor neurons in the brain and spinal cord. ALS is characterized by progressive muscle weakness, atrophy, and spasticity. The typical age at onset for most ALS patients is between 45 and 60 years, with an average survival of less than three years. The final fatal event is often the loss of the motor neurons that innervate the respiratory muscles and diaphragm. The worldwide incidence of ALS is one to two new cases per 100,000/year, whereas its prevalence is four to six affected individuals per 100,000, with a lifetime risk of ALS of one in 1,000. Most cases—approximately 90%—of ALS are sporadic (SALS), thus lacking an overt genetic cause. The remaining 10% of cases are mostly inherited in a dominant manner and are thus referred to as familial ALS (FALS). Sporadic and familial patients are largely clinically indistinguishable. ALS is traditionally viewed as lacking in cognitive impairment; however, a diagnosis of frontotemporal dementia (FTD), a neurological disorder characterized by neurodegeneration of the frontal lobe of the brain, has been reported in 3–15% of ALS cases. The human impact of ALS is enormous as it significantly affects a patient’s quality of life, with patients losing their ability to eat, speak, and live independently. At present, while significant advances have been made in palliative therapies, there is no cure or means to significantly slow disease progression. Indeed, currently just one Canadian Agency for Drugs and Technologies in Health (CADTH)/US Food and Drug Administration (FDA)-approved therapy exists (Riluzole), and it offers only a modest slowing of disease progression.

Syngap1 dysfunctions and uses thereof in diagnostic and therapeutic applications for mental retardation

Abstract: The invention identifies Syngap1 dysfunctions as causative of mental retardation. Described are methods of detecting mental retardation and methods of detecting non- syndromic mental retardation (NSMR) in a human subject. Particular methods comprise sequencing a human subject's genomic DNA for comparison with a control sequence from an unaffected individual. Also described are probes, kits, antibodies and isolated mutated Syngap1 proteins.

Hereditary spastic paraplegia initially diagnosed as cerebral palsy.

Abstract: Introduction Spastic diplegia presenting in infancy is common to both cerebral palsy (CP) and hereditary spastic paraplegia (HSP). We report the clinical and genetic features of a cohort of Alberta patients with a diagnosis of HSP, who were initially diagnosed with CP. Methods Fourteen patients with an initial diagnosis of CP were identified from an Alberta registry of HSP patients via chart review. Whole exome sequencing (WES) was performed to identify genetic causes. Results From 90 families in the database, individuals in 29 families had a pediatric presentation of spasticity, with 20 presenting under 3 years of age. Individuals from 14 families had received an initial diagnosis of CP and correct diagnosis was made after neurogenetic assessment due to symptom progression. All had early onset (<3 years) of symptoms. WES identified pathogenic or likely pathogenic mutations in nine cases involving six genes: ATL1, PLP1, PNPLA6, SACS, SPAST, and SYNE1. In five families, WES did not reveal a genetic etiology but progression of symptoms and positive family history suggests HSP is the most likely diagnosis. Conclusion In our cohort, 70% of HSP children presenting with spasticity under 3 years had been misdiagnosed with CP. In a young child presenting with spastic diplegia without clear history of prematurity, intrauterine growth restriction, infection or vascular insult, it is important to consider HSP. Accurate diagnosis has implications for prognosis, management, and recurrence risk.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

A framework for variation discovery and genotyping using next-generation DNA sequencing data

Abstract: Recent advances in sequencing technology make it possible to comprehensively catalogue genetic variation in population samples, creating a foundation for understanding human disease, ancestry and evolution. The amounts of raw data produced are prodigious and many computational steps are required to translate this output into high-quality variant calls. We present a unified analytic framework to discover and genotype variation among multiple samples simultaneously that achieves sensitive and specific results across five sequencing technologies and three distinct, canonical experimental designs. Our process includes (1) initial read mapping; (2) local realignment around indels; (3) base quality score recalibration; (4) SNP discovery and genotyping to find all potential variants; and (5) machine learning to separate true segregating variation from machine artifacts common to next-generation sequencing technologies. We discuss the application of these tools, instantiated in the Genome Analysis Toolkit (GATK), to deep whole-genome, whole-exome capture, and multi-sample low-pass (~4×) 1000 Genomes Project datasets.

Mutations in Cu/Zn superoxide dismutase gene are associated with familial amyotrophic lateral sclerosis

Abstract: Amyotrophic lateral sclerosis (ALS) is a degenerative disorder of motor neurons in the cortex, brainstem and spinal cord. Its cause is unknown and it is uniformly fatal, typically within five years. About 10% of cases are inherited as an autosomal dominant trait, with high penetrance after the sixth decade. In most instances, sporadic and autosomal dominant familial ALS (FALS) are clinically similar. We have previously shown that in some but not all FALS pedigrees the disease is linked to a genetic defect on chromosome 21q (refs 8, 9). Here we report tight genetic linkage between FALS and a gene that encodes a cytosolic, Cu/Zn-binding superoxide dismutase (SOD1), a homodimeric metalloenzyme that catalyzes the dismutation of the toxic superoxide anion O2.- to O2 and H2O2 (ref. 10). Given this linkage and the potential role of free radical toxicity in other neurodenegerative disorders, we investigated SOD1 as a candidate gene in FALS. We identified 11 different SOD1 missense mutations in 13 different FALS families.

Genetic alterations during colorectal-tumor development.

Abstract: Because most colorectal carcinomas appear to arise from adenomas, studies of different stages of colorectal neoplasia may shed light on the genetic alterations involved in tumor progression. We looked for four genetic alterations (ras-gene mutations and allelic deletions of chromosomes 5, 17, and 18) in 172 colorectal-tumor specimens representing various stages of neoplastic development. The specimens consisted of 40 predominantly early-stage adenomas from 7 patients with familial adenomatous polyposis, 40 adenomas (19 without associated foci of carcinoma and 21 with such foci) from 33 patients without familial polyposis, and 92 carcinomas resected from 89 patients. We found that ras-gene mutations occurred in 58 percent of adenomas larger than 1 cm and in 47 percent of carcinomas. However, ras mutations were found in only 9 percent of adenomas under 1 cm in size. Sequences on chromosome 5 that are linked to the gene for familial adenomatous polyposis were not lost in adenomas from the patients with polyposis but were lost in 29 to 35 percent of adenomas and carcinomas, respectively, from other patients. A specific region of chromosome 18 was deleted frequently in carcinomas (73 percent) and in advanced adenomas (47 percent) but only occasionally in earlier-stage adenomas (11 to 13 percent). Chromosome 17p sequences were usually lost only in carcinomas (75 percent). The four molecular alterations accumulated in a fashion that paralleled the clinical progression of tumors. These results are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumorigenesis.