Use of Basket Trials to Solve Sleep Problems in Patients with Rare Diseases.

The need for sleep is universal, and the ability to meet this need impacts the quality of life for patients, families, and caregivers. Although substantial progress has been made in treating rare diseases, many patients have unmet medical sleep needs, and current regulatory policy makes it prohibitively difficult to address those needs medically. This opinion reviews the rare disease experience with sleep disorders and explores potential solutions.

Modulating Endoplasmic Reticulum Chaperones and Mutant Protein Degradation in GABRG2(Q390X) Associated with Genetic Epilepsy with Febrile Seizures Plus and Dravet Syndrome.

A significant number of patients with genetic epilepsy do not obtain seizure freedom, despite developments in new antiseizure drugs, suggesting a need for novel therapeutic approaches. Many genetic epilepsies are associated with misfolded mutant proteins, including -associated Dravet syndrome, which we have previously shown to result in intracellular accumulation of mutant GABA receptor γ2(Q390X) subunit protein. Thus, a potentially promising therapeutic approach is modulation of proteostasis, such as increasing endoplasmic reticulum (ER)-associated degradation (ERAD).

γ-Aminobutyric acid transporter and GABA receptor mechanisms in and mice associated with developmental and epileptic encephalopathies.

We have previously characterized the molecular mechanisms for variants in γ-aminobutyric acid transporter 1-encoding solute carrier family 6-member 1 () and concluded that a partial or complete loss of γ-aminobutyric acid uptake due to impaired protein trafficking is the primary aetiology. Impairment of γ-aminobutyric acid transporter 1 function could cause compensatory changes in the expression of γ-aminobutyric acid receptors, which, in turn, modify disease pathophysiology and phenotype. Here we used different approaches including radioactive H γ-aminobutyric acid uptake in cells and synaptosomes, immunohistochemistry and confocal microscopy as well as brain slice surface protein biotinylation to characterize and mice, representative of a partial or a complete loss of function of mutations, respectively.

4-Phenylbutyrate promoted wild-type γ-aminobutyric acid type A receptor trafficking, reduced endoplasmic reticulum stress, and mitigated seizures in Gabrg2 mice associated with Dravet syndrome.

Objective: γ-Aminobutyric acid type A (GABA ) receptor subunit gene mutations are major causes of various epilepsy syndromes, including severe kinds such as Dravet syndrome. Although the GABA receptor is a major target for antiseizure medications, treating GABA receptor mutations with receptor channel modulators is ineffective. Here, we determined the effect of a novel treatment with 4-phenylbutyrate (PBA) in Gabrg2 knockin mice associated with Dravet syndrome.

GABA Receptor β3 Subunit Mutation N328D Heterozygous Knock-in Mice Have Lennox-Gastaut Syndrome.

Lennox-Gastaut Syndrome (LGS) is a developmental and epileptic encephalopathy (DEE) characterized by multiple seizure types, electroencephalogram (EEG) patterns, and cognitive decline. Its etiology has a prominent genetic component, including variants in that encodes the GABA receptor (GABAR) β subunit. LGS has an unknown pathophysiology, and few animal models are available for studying LGS.

4-Phenylbutyrate restored γ-aminobutyric acid uptake and reduced seizures in patient variant-bearing cell and mouse models.

We have studied the molecular mechanisms of variants in solute carrier Family 6 Member 1 associated with neurodevelopmental disorders, including various epilepsy syndromes, autism and intellectual disability. Based on functional assays of solute carrier Family 6 Member 1 variants, we conclude that partial or complete loss of γ-amino butyric acid uptake due to reduced membrane γ-amino butyric acid transporter 1 trafficking is the primary aetiology. Importantly, we identified common patterns of the mutant γ-amino butyric acid transporter 1 protein trafficking from biogenesis, oligomerization, glycosylation and translocation to the cell membrane across variants in different cell types such as astrocytes and neurons.

Astrocytic GABA transporter 1 deficit in novel SLC6A1 variants mediated epilepsy: Connected from protein destabilization to seizures in mice and humans.

Objective: Mutations in γ-aminobutyric acid (GABA) transporter 1 (GAT-1)-encoding SLC6A1 have been associated with myoclonic atonic epilepsy and other phenotypes. We determined the patho-mechanisms of the mutant GAT-1, in order to identify treatment targets.

Methods: We conducted whole-exome sequencing of patients with myoclonic atonic epilepsy (MAE) and characterized the seizure phenotypes and EEG patterns.

Disruption of the Ubiquitin-Proteasome System and Elevated Endoplasmic Reticulum Stress in Epilepsy.

The epilepsies are a broad group of conditions characterized by repeated seizures, and together are one of the most common neurological disorders. Additionally, epilepsy is comorbid with many neurological disorders, including lysosomal storage diseases, syndromic intellectual disability, and autism spectrum disorder. Despite the prevalence, treatments are still unsatisfactory: approximately 30% of epileptic patients do not adequately respond to existing therapeutics, which primarily target ion channels.

Common molecular mechanisms of SLC6A1 variant-mediated neurodevelopmental disorders in astrocytes and neurons.

Solute carrier family 6 member 1 (SLC6A1) is abundantly expressed in the developing brain even before the CNS is formed. Its encoded GABA transporter 1 (GAT-1) is responsible for the reuptake of GABA into presynaptic neurons and glia, thereby modulating neurotransmission. GAT-1 is expressed globally in the brain, in both astrocytes and neurons.

Genetic mosaicism, intrafamilial phenotypic heterogeneity, and molecular defects of a novel missense SLC6A1 mutation associated with epilepsy and ADHD.

Background: Mutations in SLC6A1, encoding γ-aminobutyric acid (GABA) transporter 1 (GAT-1), have been recently associated with a spectrum of neurodevelopmental disorders ranging from variable epilepsy syndromes, intellectual disability (ID), autism and others. To date, most identified mutations are de novo. We here report a pedigree of two siblings associated with myoclonic astatic epilepsy, attention deficit hyperactivity disorder (ADHD), and ID.

Endoplasmic reticulum stress increases inflammatory cytokines in an epilepsy mouse model Gabrg2 knockin: A link between genetic and acquired epilepsy?

Objective: Neuroinflammation is a major theme in epilepsy, which has been characterized in acquired epilepsy but is poorly understood in genetic epilepsy. γ-Aminobutyric acid type A receptor subunit gene mutations are significant causes of epilepsy, and we have studied the pathophysiology directly resulting from defective receptor channels. Here, we determined the proinflammatory factors in a genetic mouse model, the Gabrg2 knockin (KI).

Endoplasmic reticulum retention and degradation of a mutation in SLC6A1 associated with epilepsy and autism.

Mutations in SLC6A1, encoding γ-aminobutyric acid (GABA) transporter 1 (GAT-1), have been recently associated with a spectrum of epilepsy syndromes, intellectual disability and autism in clinic. However, the pathophysiology of the gene mutations is far from clear. Here we report a novel SLC6A1 missense mutation in a patient with epilepsy and autism spectrum disorder and characterized the molecular defects of the mutant GAT-1, from transporter protein trafficking to GABA uptake function in heterologous cells and neurons.

Synaptic clustering differences due to different GABRB3 mutations cause variable epilepsy syndromes.

GABRB3 is highly expressed early in the developing brain, and its encoded β3 subunit is critical for GABAA receptor assembly and trafficking as well as stem cell differentiation in embryonic brain. To date, over 400 mutations or variants have been identified in GABRB3. Mutations in GABRB3 have been increasingly recognized as a major cause for severe paediatric epilepsy syndromes such as Lennox-Gastaut syndrome, Dravet syndrome and infantile spasms with intellectual disability as well as relatively mild epilepsy syndromes such as childhood absence epilepsy.

The DEAD-box helicase Mss116 plays distinct roles in mitochondrial ribogenesis and mRNA-specific translation.

Members of the DEAD-box family are often multifunctional proteins involved in several RNA transactions. Among them, yeast Saccharomyces cerevisiae Mss116 participates in mitochondrial intron splicing and, under cold stress, also in mitochondrial transcription elongation. Here, we show that Mss116 interacts with the mitoribosome assembly factor Mrh4, is required for efficient mitoribosome biogenesis, and consequently, maintenance of the overall mitochondrial protein synthesis rate.

Longitudinal changes in calcium and vitamin D intakes and relationship to bone mineral density in a prospective population-based study: the Canadian Multicentre Osteoporosis Study (CaMos).

Objectives: Our objective was to study changes in calcium and vitamin D intakes over time, and their cross-sectional and longitudinal associations with bone mineral density (BMD).

Methods: We followed 9382 women and men aged ≥25 and 899 aged 16-24, for 10 and 2 years respectively.

Results: Calcium and vitamin D intakes increased over time in adults, but decreased in women aged 16-18.

Dietary patterns and incident low-trauma fractures in postmenopausal women and men aged ≥ 50 y: a population-based cohort study.

Background: Previous research has shown that dietary patterns are related to the risk of several adverse health outcomes, but the relation of these patterns to skeletal fragility is not well understood.

Objective: Our objective was to determine the relation between dietary patterns and incident fracture and possible mediation of this relation by body mass index, bone mineral density, or falls.

Design: We performed a retrospective cohort study based on the Canadian Multicentre Osteoporosis Study-a randomly selected population-based cohort.

25-Hydroxyvitamin D in Canadian adults: biological, environmental, and behavioral correlates.

Summary: We assessed vitamin D status and its correlates in the population-based Canadian Multicentre Osteoporosis Study (CaMos). Results showed that serum 25-hydroxyvitamin D levels <75 nmol/L were common. Given Canada's high latitude, attention should be given to strategies for enhancing vitamin D status in the population.

Health-related quality of life in Canadian adolescents and young adults: normative data using the SF-36.

Objectives: Normative data for the SF-36 measure of health-related quality of life (HRQOL) exist for those over 25 years of age, based on data from the population-based Canadian Multicentre Osteoporosis Study (CaMos). CaMos recently recruited a sample of young Canadians aged between 16 and 24 years. The purpose of this study was to develop normative SF-36 data for this age group.

Dietary patterns in Canadian men and women ages 25 and older: relationship to demographics, body mass index, and bone mineral density.

Background: Previous research has shown that underlying dietary patterns are related to the risk of many different adverse health outcomes, but the relationship of these underlying patterns to skeletal fragility is not well understood. The objective of the study was to determine whether dietary patterns in men (ages 25-49, 50+) and women (pre-menopause, post-menopause) are related to femoral neck bone mineral density (BMD) independently of other lifestyle variables, and whether this relationship is mediated by body mass index.

Methods: We performed an analysis of 1928 men and 4611 women participants in the Canadian Multicentre Osteoporosis Study, a randomly selected population-based longitudinal cohort.

Calcium and vitamin D intakes in an adult Canadian population.

Purpose: Calcium and vitamin D intakes from food and supplements were estimated in Canadian men and women.

Methods: Calcium intakes from both diet and supplements and vitamin D intakes from fortified milk and supplements were estimated using cross-sectional data from 9423 randomly selected subjects aged 25 years or older, who were participating in a longitudinal study on osteoporosis. Subjects completed an abbreviated food frequency questionnaire administered by a trained interviewer between July 1995 and December 1997.

The association between body mass index and health-related quality of life: data from CaMos, a stratified population study.

Background: Deviation from normal weight is associated with health risks, but less is known about the association between weight and health-related quality of life (HRQOL). We investigated this in the context of a population-based study, using a standard five-category weight classification system based on body mass index (BMI).

Methods: The Canadian Multicentre Osteoporosis Study is a randomly selected sample of men and women over 25 years of age from nine centres across Canada.

Changes in body mass index in Canadians over a five-year period: results of a prospective, population-based study.

Background: The initiation of the Canadian Multicentre Osteoporosis Study in 1996, and subsequent follow-up of the cohort 5 years later, provided longitudinal body mass index (BMI) data for a random sample of Canadians.

Methods: Height and weight were measured at baseline and 5 years and used to calculate BMI and assign one of six weight categories. Multiple imputation was used to adjust for missing weight at year 5.

Stability of normative data for the SF-36: results of a three-year prospective study in middle-aged Canadians.

Background: The SF-36 is widely used to assess health-related quality of life (HRQOL), but with few longitudinal studies in healthy populations, it is difficult to quantify its natural history. This is important because any measure of change following an intervention may be confounded by natural changes in HRQOL. This paper assesses mean changes in SF-36 scores over a 3-year period in men and women between the ages of 40 and 59 years at baseline.

The association between osteoporotic fractures and health-related quality of life as measured by the Health Utilities Index in the Canadian Multicentre Osteoporosis Study (CaMos).

Osteoporotic fractures can be a major cause of morbidity. It is important to determine the impact of fractures on health-related quality of life (HRQL). A total of 3,394 women and 1,122 men 50 years of age and older, who were recruited for the Canadian Multicentre Osteoporosis Study (CaMos), participated in this cross-sectional study.

Associations among disease conditions, bone mineral density, and prevalent vertebral deformities in men and women 50 years of age and older: cross-sectional results from the Canadian Multicentre Osteoporosis Study.

This cross-sectional cohort study of 5566 women and 2187 men 50 years of age and older in the population-based Canadian Multicentre Osteoporosis Study was conducted to determine whether reported past diseases are associated with bone mineral density or prevalent vertebral deformities. We examined 12 self-reported disease conditions including diabetes mellitus (types 1 or 2), nephrolithiasis, hypertension, heart attack, rheumatoid arthritis, thyroid disease, breast cancer, inflammatory bowel disease, neuromuscular disease, Paget's disease, and chronic obstructive pulmonary disease. Multivariate linear and logistic regression analyses were performed to determine whether there were associations among these disease conditions and bone mineral density of the lumbar spine, femoral neck, and trochanter, as well as prevalent vertebral deformities.