RESUMEN
Background: Episodic ataxias are rare neurological disorders characterized by recurring episodes of imbalance and coordination difficulties. Obtaining definitive molecular diagnoses poses challenges, as clinical presentation is highly heterogeneous, and literature on the underlying genetics is limited. While the advent of high-throughput sequencing technologies has significantly contributed to Mendelian disorders genetics, interpretation of variants of uncertain significance and other limitations inherent to individual methods still leaves many patients undiagnosed. This study aimed to investigate the utility of multi-omics for the identification and validation of molecular candidates in a cohort of complex cases of ataxia with episodic presentation. Methods: Eight patients lacking molecular diagnosis despite extensive clinical examination were recruited following standard genetic testing. Whole genome and RNA sequencing were performed on samples isolated from peripheral blood mononuclear cells. Integration of expression and splicing data facilitated genomic variants prioritization. Subsequently, long-read sequencing played a crucial role in the validation of those candidate variants. Results: Whole genome sequencing uncovered pathogenic variants in four genes (SPG7, ATXN2, ELOVL4, PMPCB). A missense and a nonsense variant, both previously reported as likely pathogenic, configured in trans in individual #1 (SPG7: c.2228T>C/p.I743T, c.1861C>T/p.Q621*). An ATXN2 microsatellite expansion (CAG32) in another late-onset case. In two separate individuals, intronic variants near splice sites (ELOVL4: c.541 + 5G>A; PMPCB: c.1154 + 5G>C) were predicted to induce loss-of-function splicing, but had never been reported as disease-causing. Long-read sequencing confirmed the compound heterozygous variants configuration, repeat expansion length, as well as splicing landscape for those pathogenic variants. A potential genetic modifier of the ATXN2 expansion was discovered in ZFYVE26 (c.3022C>T/p.R1008*). Conclusion: Despite failure to identify pathogenic variants through clinical genetic testing, the multi-omics approach enabled the molecular diagnosis in 50% of patients, also giving valuable insights for variant prioritization in remaining cases. The findings demonstrate the value of long-read sequencing for the validation of candidate variants in various scenarios. Our study demonstrates the effectiveness of leveraging complementary omics technologies to unravel the underlying genetics in patients with unresolved rare diseases such as ataxia. Molecular diagnoses not only hold significant promise in improving patient care management, but also alleviates the burden of diagnostic odysseys, more broadly enhancing quality of life.
RESUMEN
INTRODUCTION: Women with obesity are at a higher risk of infertility as well as gestational and neonatal complications. Lifestyle changes are universally recommended for women with obesity seeking fertility treatments, but such intervention has only been assessed in very few robust studies. This study's objectives are therefore to assess the clinical outcomes and cost-effectiveness of an interdisciplinary lifestyle intervention (the Fit-For-Fertility Programme; FFFP) targeting women with obesity and subfertility in a diverse population. METHODS AND ANALYSIS: This pragmatic multicentre randomised controlled trial (RCT) will include 616 women with obesity (body mass index ≥30 kg/m2 or ≥27 kg/m2 with polycystic ovary syndrome or at-risk ethnicities) who are evaluated at a Canadian fertility clinic for subfertility. Women will be randomised either to (1) the FFFP (experimental arm) alone for 6 months, and then in combination with usual care for infertility if not pregnant; or (2) directly to usual fertility care (control arm). Women in the intervention group benefit from the programme up to 18 months or, if pregnant, up to 24 months or the end of the pregnancy (whichever comes first). Women from both groups are evaluated every 6 months for a maximum of 18 months. The primary outcome is live birth rate at 24 months. Secondary outcomes include fertility, pregnancy and neonatal outcomes; lifestyle and anthropometric measures; and cost-effectiveness. Qualitative data collected from focus groups of participants and professionals will also be analysed. ETHICS AND DISSEMINATION: This research study has been approved by the Research Ethics Board (REB) of Centre intégré universtaire de santé et des services sociaux de l'Estrie-CHUS (research coordinating centre) on 10 December 2018 and has been or will be approved successively by each participating centres' REB. This pragmatic RCT will inform decision-makers on improving care trajectories and policies regarding fertility treatments for women with obesity and subfertility. TRIAL REGISTRATION NUMBER: NCT03908099. PROTOCOL VERSION: 1.1, 13 April 2019.
