EEFSEC deficiency: A selenopathy with early-onset neurodegeneration.

Inborn errors of selenoprotein expression arise from deleterious variants in genes encoding selenoproteins or selenoprotein biosynthetic factors, some of which are associated with neurodegenerative disorders. This study shows that bi-allelic selenocysteine tRNA-specific eukaryotic elongation factor (EEFSEC) variants cause selenoprotein deficiency, leading to progressive neurodegeneration. EEFSEC deficiency, an autosomal recessive disorder, manifests with global developmental delay, progressive spasticity, ataxia, and seizures.

From spastic paraplegia to infantile neurodegenerative disorder: Expanding the phenotypic spectrum associated with biallelic SPAST variants.

Purpose: Heterozygous pathogenic variants in SPAST are known to cause Hereditary Spastic Paraplegia 4 (SPG4), the most common form of HSP, characterized by progressive bilateral lower limbs spasticity with frequent sphincter disorders. However, there are very few descriptions in the literature of patients carrying biallelic variants in SPAST.

Methods: Targeted Sanger sequencing, panel sequencing and exome sequencing were used to identify the genetic causes in 9 patients from 6 unrelated families with symptoms of HSP or infantile neurodegenerative disorder.

Rare Spinocerebellar Ataxia Types in Canada: A Case Series and Review of the Literature.

Background: There is limited information on rare spinocerebellar ataxia (SCA) variants, particularly in the Canadian population. This study aimed to describe the demographic and clinical features of uncommon SCA subtypes in Canada and compare them with international data.

Methods: We conducted a case series and literature review of adult patients with rare SCA subtypes, including SCA5, SCA7, SCA12, SCA14, SCA15, SCA28, SCA34, SCA35 and SCA36.

Levodopa-Carbidopa Intestinal Gel for Parkinson's Disease over 11 years: One Center's "Real-World" Experience.

Background: Levodopa-carbidopa intestinal gel (LCIG) therapy has been shown to be a safe and effective treatment for advanced Parkinson's disease (PD). Limited data are available regarding long-term benefits and complications in Canada. Objective of the study was to review long-term experience and clinical outcomes in PD patients with LCIG therapy over 11 years in a multidisciplinary University clinic setting.

International Genetic Testing and Counseling Practices for Parkinson's Disease.

Background: There is growing clinical and research utilization of genetic testing in Parkinson's disease (PD), including direct-to-consumer testing.

Objectives: The aim is to determine the international landscape of genetic testing in PD to inform future worldwide recommendations.

Methods: A web-based survey assessing current practices, concerns, and barriers to genetic testing and counseling was administered to the International Parkinson and Movement Disorders Society membership.

HostSeq: a Canadian whole genome sequencing and clinical data resource.

HostSeq was launched in April 2020 as a national initiative to integrate whole genome sequencing data from 10,000 Canadians infected with SARS-CoV-2 with clinical information related to their disease experience. The mandate of HostSeq is to support the Canadian and international research communities in their efforts to understand the risk factors for disease and associated health outcomes and support the development of interventions such as vaccines and therapeutics. HostSeq is a collaboration among 13 independent epidemiological studies of SARS-CoV-2 across five provinces in Canada.

Demographics and Clinical Characteristics of Autosomal Dominant Spinocerebellar Ataxia in Canada.

Background: Autosomal dominant (AD) spinocerebellar ataxias (SCAs) encompass a large group of rare disorders, which occurs in individuals of different ethnic backgrounds. To date, demographics, and clinical descriptions of AD SCA in Canada are lacking.

Methods: A retrospective chart review of patients with a genetically confirmed diagnosis of AD SCAs was performed at five tertiary centers across Canada in the provinces of Quebec, Alberta, and Ontario.

Hereditary spastic paraplegia initially diagnosed as cerebral palsy.

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.

Predictive modeling of spread in adult-onset isolated dystonia: Key properties and effect of tremor inclusion.

Background And Purpose: Several clinical and demographic factors relate to anatomic spread of adult-onset isolated dystonia, but a predictive model is still lacking. The aims of this study were: (i) to develop and validate a predictive model of anatomic spread of adult-onset isolated dystonia; and (ii) to evaluate whether presence of tremor associated with dystonia influences model predictions of spread.

Methods: Adult-onset isolated dystonia participants with focal onset from the Dystonia Coalition Natural History Project database were included.

Longitudinal Change in Quality of Life in Neurological Disorders Measures Over 3 Years in Patients with Early Parkinson's Disease.

Background: The Quality of Life in Neurological Disorders (Neuro-QoL) is a publicly available health-related quality-of-life measurement system.

Objective: The aim of this study was to evaluate the utility of Neuro-QoL item banks as outcome measures for clinical trials in Parkinson's disease.

Methods: An analysis of Neuro-QoL responsiveness to change and construct validity was performed in a multicenter clinical trial cohort.

Vitamins and Infusion of Levodopa-Carbidopa Intestinal Gel.

Levodopa-carbidopa intestinal gel infusion (LCIG) is an established therapy for advanced Parkinson disease (PD), resulting in a significant improvement of quality of life. With increased LCIG adoption worldwide, potential complications due to abnormal vitamin absorption or metabolism have been reported in these patients. Neurologists are unfamiliar with vitamins physiology and pathophysiological mechanisms in case of their deficiency.

Evidence for Non-Mendelian Inheritance in Spastic Paraplegia 7.

Background: Although the typical inheritance of spastic paraplegia 7 is recessive, several reports have suggested that SPG7 variants may also cause autosomal dominant hereditary spastic paraplegia (HSP).

Objectives: We aimed to conduct an exome-wide genetic analysis on a large Canadian cohort of HSP patients and controls to examine the association of SPG7 and HSP.

Methods: We analyzed 585 HSP patients from 372 families and 1175 controls, including 580 unrelated individuals.

Channelopathies Are a Frequent Cause of Genetic Ataxias Associated with Cerebellar Atrophy.

Background: Cerebellar atrophy is a nonspecific imaging finding observed in a number of neurological disorders. Genetic ataxias associated with cerebellar atrophy are a heterogeneous group of conditions, rendering the approach to diagnosis challenging.

Objectives: To define the spectrum of genetic ataxias associated with cerebellar atrophy in a Canadian cohort and the diagnostic yield of exome sequencing for this group of conditions.

Assessing non-Mendelian inheritance in inherited axonopathies.

Purpose: Inherited axonopathies (IA) are rare, clinically and genetically heterogeneous diseases that lead to length-dependent degeneration of the long axons in central (hereditary spastic paraplegia [HSP]) and peripheral (Charcot-Marie-Tooth type 2 [CMT2]) nervous systems. Mendelian high-penetrance alleles in over 100 different genes have been shown to cause IA; however, about 50% of IA cases do not receive a genetic diagnosis. A more comprehensive spectrum of causative genes and alleles is warranted, including causative and risk alleles, as well as oligogenic multilocus inheritance.

The R941L mutation in MYH14 disrupts mitochondrial fission and associates with peripheral neuropathy.

Background: Peripheral neuropathies are often caused by disruption of genes responsible for myelination or axonal transport. In particular, impairment in mitochondrial fission and fusion are known causes of peripheral neuropathies. However, the causal mechanisms for peripheral neuropathy gene mutations are not always known.