The human fragile X mental retardation 1 (FMR1) gene contains a (CGG)(n) trinucleotide repeat in its 5' untranslated region (5'UTR). Expansions of this repeat result in a number of clinical disorders ...with distinct molecular pathologies, including fragile X syndrome (FXS; full mutation range, greater than 200 CGG repeats) and fragile X-associated tremor/ataxia syndrome (FXTAS; premutation range, 55-200 repeats). Study of these diseases has been limited by an inability to sequence expanded CGG repeats, particularly in the full mutation range, with existing DNA sequencing technologies. Single-molecule, real-time (SMRT) sequencing provides an approach to sequencing that is fundamentally different from other "next-generation" sequencing platforms, and is well suited for long, repetitive DNA sequences. We report the first sequence data for expanded CGG-repeat FMR1 alleles in the full mutation range that reveal the confounding effects of CGG-repeat tracts on both cloning and PCR. A unique feature of SMRT sequencing is its ability to yield real-time information on the rates of nucleoside addition by the tethered DNA polymerase; for the CGG-repeat alleles, we find a strand-specific effect of CGG-repeat DNA on the interpulse distance. This kinetic signature reveals a novel aspect of the repeat element; namely, that the particular G bias within the CGG/CCG-repeat element influences polymerase activity in a manner that extends beyond simple nearest-neighbor effects. These observations provide a baseline for future kinetic studies of repeat elements, as well as for studies of epigenetic and other chemical modifications thereof.
Abstract
Introduction
Treatment with sodium oxybate (SXB) has been associated with weight loss in patients with narcolepsy. Lower-sodium oxybate (LXB) contains the same active moiety as SXB, with 92% ...less sodium, and is approved in the US for treatment of cataplexy or excessive daytime sleepiness in patients ≥7 years of age with narcolepsy and for treatment of adults with idiopathic hypersomnia. This analysis assessed weight changes after 14 weeks of open-label LXB treatment in a phase 3 clinical study in patients with narcolepsy (NCT03030599).
Methods
Participants 18‒70 years of age with narcolepsy with cataplexy (taking SXB only, SXB+other anticataplectics, or other anticataplectics, or who were anticataplectic-naive at study entry) began LXB treatment in a 12-week, open-label, optimized treatment and titration period, followed by a 2-week stable-dose period (SDP) on LXB.
Results
Study participants (N=201) had a mean (SD) age of 37.2 (12.2) years. At baseline, mean (SD) weight and body mass index (BMI) were 83.7 (19.2) kg and 28.8 (6.1) kg/m2, respectively; 31.8% of participants (64/201) were normal weight (BMI 18.5 to <25 kg/m2), 31.8% (64/201) were overweight (BMI 25 to <30 kg/m2), and 35.3% (71/201) were obese (BMI ≥30 kg/m2). At the end of SDP, mean (SD) weight and BMI changes in SXB-only (n=45 weight; n=44 BMI), SXB+anticataplectics (n=14), other-anticataplectics (n=23), and anticataplectic-naive (n=65) participants were, respectively, −0.2 (2.5) kg and 0.0 (0.9) kg/m2, −1.0 (1.9) kg and −0.3 (0.6) kg/m2, −2.3 (4.0) kg and −0.8 (1.4) kg/m2, and −2.5 (3.8) kg and −0.9 (1.3) kg/m2. Weight loss ≥5% at the end of SDP occurred in 6.7% of SXB-only, 0.0% of SXB+anticataplectics, 21.7% of other-anticataplectics, and 27.7% of anticataplectic-naive participants. In normal weight, overweight, and obese participants at baseline, mean (SD) decreases in weight at the end of SDP were −1.5 (3.1) kg, −3.3 (3.5) kg, and −2.6 (4.7) kg, respectively (participants who were oxybate-naive at study entry), and −0.1 (1.8) kg, −1.0 (2.4) kg, and 0.2 (2.8) kg, respectively (participants taking SXB at study entry).
Conclusion
In this study, adults with narcolepsy who were oxybate-naive at study entry experienced greater weight loss during LXB treatment compared with adults previously taking SXB.
Support (If Any)
Jazz Pharmaceuticals.
Abstract
Introduction
Treatment with sodium oxybate (SXB) has been associated with weight loss in patients with narcolepsy. Lower-sodium oxybate (LXB) contains the same active moiety as SXB, with 92% ...less sodium, and is approved in the United States for the treatment of idiopathic hypersomnia in adults. This analysis assessed weight changes during LXB treatment in a phase 3 clinical study (NCT03533114).
Methods
Participants 18–75 years of age with idiopathic hypersomnia (treatment naive or taking an alerting agent with or without SXB at study entry) began LXB treatment in a 10- to 14-week, open-label, optimized treatment and titration period. After a 2-week stable-dose period (SDP) on their optimized dose of LXB, participants were randomized (1:1) to LXB or placebo for a 2-week, double-blind, randomized withdrawal period, followed by a 24-week open-label extension (OLE).
Results
Study participants (N=154) had a mean (SD) age of 40.3 (13.7) years; baseline mean (SD) weight was 76.9 (18.6) kg, and baseline mean (SD) body mass index (BMI) was 27.1 (5.9) kg/m2. At baseline, 1.3% (2/154) of participants were underweight (BMI <18.5 kg/m2), 40.3% (62/154) of participants had a normal weight (BMI 18.5 to <25 kg/m2), 33.8% (52/154) were overweight (BMI 25 to <30 kg/m2), and 24.7% (38/154) were obese (BMI ≥30 kg/m2). At the end of the SDP, 28.7% (31/108) of participants had weight loss ≥5%. Mean (SD) change in weight at the end of the SDP (n=108) was −2.5 (4.1) kg. Mean (SD) decreases in weight at the end of SDP were numerically greater in participants with higher baseline BMI (normal baseline BMI, −1.8 3.0 kg; overweight baseline BMI, −2.8 3.1 kg; obese baseline BMI, −3.2 5.9 kg).
Conclusion
In this phase 3 clinical trial, adults with idiopathic hypersomnia treated with LXB experienced weight loss, including weight loss ≥5% in 28.7% of participants. Mean weight loss was greater in participants with a higher baseline BMI.
Support (If Any)
Jazz Pharmaceuticals.
Current clinical genomics assays primarily utilize short-read sequencing (SRS), but SRS has limited ability to evaluate repetitive regions and structural variants. Long-read sequencing (LRS) has ...complementary strengths, and we aimed to determine whether LRS could offer a means to identify overlooked genetic variation in patients undiagnosed by SRS.
We performed low-coverage genome LRS to identify structural variants in a patient who presented with multiple neoplasia and cardiac myxomata, in whom the results of targeted clinical testing and genome SRS were negative.
This LRS approach yielded 6,971 deletions and 6,821 insertions>50bp. Filtering for variants that are absent in an unrelated control and overlap a disease gene coding exon identified three deletions and three insertions. One of these, a heterozygous 2,184bp deletion, overlaps the first coding exon of PRKAR1A, which is implicated in autosomal dominant Carney complex. RNA sequencing demonstrated decreased PRKAR1A expression. The deletion was classified as pathogenic based on guidelines for interpretation of sequence variants.
This first successful application of genome LRS to identify a pathogenic variant in a patient suggests that LRS has significant potential for the identification of disease-causing structural variation. Larger studies will ultimately be required to evaluate the potential clinical utility of LRS.
FMR1 premutation carriers (55–200 CGG repeats) are at risk for developing Fragile X-associated Tremor/Ataxia Syndrome (FXTAS), an adult onset neurodegenerative disorder. Approximately 20% of female ...carriers will develop Fragile X-associated Primary Ovarian Insufficiency (FXPOI), in addition to a number of clinical problems affecting premutation carriers throughout their life span. Marked elevation in FMR1 mRNA levels have been observed with premutation alleles resulting in RNA toxicity, the leading molecular mechanism proposed for the FMR1 associated disorders observed in premutation carriers.
The FMR1 gene undergoes alternative splicing and we have recently reported that the relative abundance of all FMR1 mRNA isoforms is significantly increased in premutation carriers.
In this study, we characterized the transcriptional FMR1 isoforms distribution pattern in different tissues and identified a total of 49 isoforms, some of which observed only in premutation carriers and which might play a role in the pathogenesis of FXTAS.
Further, we investigated the distribution pattern and expression levels of the FMR1 isoforms in asymptomatic premutation carriers and in those with FXTAS and found no significant differences between the two groups.
Our findings suggest that the characterization of the expression levels of the different FMR1 isoforms is fundamental for understanding the regulation of the FMR1 gene as imbalance in their expression could lead to an altered functional diversity with neurotoxic consequences. Their characterization will also help to elucidating the mechanism(s) by which “toxic gain of function” of the FMR1 mRNA may play a role in FXTAS and/or in the other FMR1-associated conditions.
•49 FMR1 isoforms were identified, but no differential expression was found in tissues.•Characterizing the FMR1 isoforms expression levels helps understand the FMR1 gene regulation•This study elucidate one of the mechanisms of FMR1-associated disorders.
To evaluate 6-month efficacy and safety of low-sodium oxybate (LXB) in people with idiopathic hypersomnia during an open-label extension period (OLE) of a phase 3 clinical trial.
Efficacy measures ...included the Epworth Sleepiness Scale (ESS), Idiopathic Hypersomnia Severity Scale (IHSS), Patient Global Impression of Change (PGIc), Functional Outcomes of Sleep Questionnaire, short version (FOSQ-10), and Work Productivity and Activity Impairment Questionnaire: Specific Health Problem (WPAI:SHP). Treatment-emergent adverse events (TEAEs) were collected throughout the OLE.
The OLE population included 106 participants. Most were female (71%) and White (83%), and the mean (SD) age was 41.0 (13.8) years. ESS scores decreased (improved) during OLE (mean SD, study baseline: 16.3 2.8; OLE week (W)2: 6.7 4.7; OLE end: 5.3 3.7), and IHSS total scores trended toward a decrease (study baseline: 32.6 7.3; OLE W2: 16.2 8.9; OLE end: 14.8 8.6. Median (min, max) paired differences from OLE W2 to OLE end were ESS, -1.0 (-20, 7), nominal
=0.012; IHSS, -1.0 (-31, 19), nominal
=0.086). The proportion of participants reporting PGIc ratings of "very much improved" increased from 36.7% at OLE W2 to 53.8% at OLE end. FOSQ-10 and WPAI:SHP scores remained stable during OLE. The incidence of newly reported TEAEs decreased over the duration of OLE.
Efficacy and safety of LXB were maintained or improved during the 6-month OLE, supporting long-term treatment with LXB in adults with idiopathic hypersomnia.
Registry: ClinicalTrials.gov; Identifier: NCT03533114 and Registry: EU Clinical Trials; Identifier: 2018-001311-79.
Purpose: To report the efficacy and safety of lower-sodium oxybate (LXB; XywavR) during the open-label titration and optimization period (OLT) and stable-dose period (SDP) in a clinical study for the ...treatment of idiopathic hypersomnia. Patients and Methods: Data were collected during treatment titration and optimization in a phase 3 randomized withdrawal trial in adults (18-75 years of age) with idiopathic hypersomnia who took LXB treatment (once, twice, or thrice nightly, administered orally) in the OLT (10-14 weeks), followed by the 2-week, open-label SDP. Endpoints included the Epworth Sleepiness Scale (ESS), Idiopathic Hypersomnia Severity Scale (IHSS), Patient Global Impression of Change, Clinical Global Impression of Change, Functional Outcomes of Sleep Questionnaire (FOSQ)-10, and Work Productivity and Activity Impairment Questionnaire: Specific Health Problem (WPALSHP). Results: The safety population included 154 participants; the modified intent-to-treat population comprised 115 participants. During open-label treatment, mean (SD) ESS scores improved (decreased) from 15.7 (3.8) at baseline to 6.1 (4.0) at end of SDP, and IHSS scores improved (decreased) from 31.6 (8.3) to 15.3 (8.5). Improvements were also observed during OLT in each individual IHSS item and in FOSQ-10 and WPALSHP scores. Thirty-five (22.7%) participants discontinued during OLT and SDP, 22 (14.3%) due to treatment-emergent adverse events (TEAEs) during OLT and SDP. The most frequent TEAEs in the first 4 weeks were nausea, headache, dizziness, and dry mouth; TEAE incidence decreased throughout OLT and SDP (weeks 1-4, n = 87 56.5%; weeks 13-16, n = 39 31.7%). Conclusion: During open-label treatment with LXB, participants showed clinically meaningful improvements in idiopathic hypersomnia symptoms and in quality of life and functional measures. TEAE incidence declined over LXB titration and optimization. Keywords: excessive daytime sleepiness, hypersomnolence, quality of life, pharmacotherapy
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