Unravelling undiagnosed rare disease cases by HiFi long-read genome sequencing.

Solve-RD is a pan-European rare disease (RD) research program that aims to identify disease-causing genetic variants in previously undiagnosed RD families. We utilised 10-fold coverage HiFi long-read sequencing (LRS) for detecting causative structural variants (SVs), single nucleotide variants (SNVs), insertion-deletions (InDels), and short tandem repeat (STR) expansions in extensively studied RD families without clear molecular diagnoses. Our cohort includes 293 individuals from 114 genetically undiagnosed RD families selected by European Rare Disease Network (ERN) experts. Of these, 21 families were affected by so-called 'unsolvable' syndromes for which genetic causes remain unknown, and 93 families with at least one individual affected by a rare neurological, neuromuscular, or epilepsy disorder without genetic diagnosis despite extensive prior testing. Clinical interpretation and orthogonal validation of variants in known disease genes yielded thirteen novel genetic diagnoses due to de novo and rare inherited SNVs, InDels, SVs, and STR expansions. In an additional four families, we identified a candidate disease-causing SV affecting several genes including an MCF2 / FGF13 fusion and PSMA3 deletion. However, no common genetic cause was identified in any of the 'unsolvable' syndromes. Taken together, we found (likely) disease-causing genetic variants in 13.0% of previously unsolved families and additional candidate disease-causing SVs in another 4.3% of these families. In conclusion, our results demonstrate the added value of HiFi long-read genome sequencing in undiagnosed rare diseases.

Increased Diagnostic Yield by Reanalysis of Whole Exome Sequencing Data in Mitochondrial Disease.

Background: The genetic diagnosis of mitochondrial disorders is complicated by its genetic and phenotypic complexity. Next generation sequencing techniques have much improved the diagnostic yield for these conditions. A cohort of individuals with multiple respiratory chain deficiencies, reported in the literature 10 years ago, had a diagnostic rate of 60% by whole exome sequencing (WES) but 40% remained undiagnosed. Objective: We aimed to identify a genetic diagnosis by reanalysis of the WES data for the undiagnosed arm of this 10-year-old cohort of patients with suspected mitochondrial disorders. Methods: The WES data was transferred and processed by the RD-Connect Genome-Phenome Analysis Platform (GPAP) using their standardized pipeline. Variant prioritisation was carried out on the RD-Connect GPAP. Results: Singleton WES data from 14 individuals was reanalysed. We identified a possible or likely genetic diagnosis in 8 patients (8/14, 57%). The variants identified were in a combination of mitochondrial DNA (n = 1, MT-TN), nuclear encoded mitochondrial genes (n = 2, PDHA1, and SUCLA2) and nuclear genes associated with nonmitochondrial disorders (n = 5, PNPLA2, CDC40, NBAS and SLC7A7). Variants in both the NBAS and CDC40 genes were established as disease causing after the original cohort was published. We increased the diagnostic yield for the original cohort by 15% without generating any further genomic data. CONCLUSIONS: In the era of multiomics we highlight that reanalysis of existing WES data is a valid tool for generating additional diagnosis in patients with suspected mitochondrial disease, particularly when more time has passed to allow for new bioinformatic pipelines to emerge, for the development of new tools in variant interpretation aiding in reclassification of variants and the expansion of scientific knowledge on additional genes.

Structural variant calling and clinical interpretation in 6224 unsolved rare disease exomes.

Structural variants (SVs), including large deletions, duplications, inversions, translocations, and more complex events have the potential to disrupt gene function resulting in rare disease. Nevertheless, current pipelines and clinical decision support systems for exome sequencing (ES) tend to focus on small alterations such as single nucleotide variants (SNVs) and insertions-deletions shorter than 50 base pairs (indels). Additionally, detection and interpretation of large copy-number variants (CNVs) are frequently performed. However, detection of other types of SVs in ES data is hampered by the difficulty of identifying breakpoints in off-target (intergenic or intronic) regions, which makes robust identification of SVs challenging. In this paper, we demonstrate the utility of SV calling in ES resulting in a diagnostic yield of 0.4% (23 out of 5825 probands) for a large cohort of unsolved patients collected by the Solve-RD consortium. Remarkably, 8 out of 23 pathogenic SV were not found by comprehensive read-depth-based CNV analysis, resulting in a 0.13% increased diagnostic value.

Partial loss of desmin expression due to a leaky splice site variant in the human DES gene is associated with neuromuscular transmission defects.

Recessive desminopathies are rare and often present as severe early-onset myopathy. Here we report a milder phenotype in three unrelated patients from southern India (2 M, 1F) aged 16, 21, and 22 years, who presented with childhood-onset, gradually progressive, fatigable limb-girdle weakness, ptosis, speech and swallowing difficulties, without cardiac involvement. Serum creatine kinase was elevated, and repetitive nerve stimulation showed decrement in all. Clinical improvement was noted with pyridostigmine and salbutamol in two patients. All three patients had a homozygous substitution in intron 5: DES(NM_001927.4):c.1023+5G>A, predicted to cause a donor splice site defect. Muscle biopsy with ultrastructural analysis suggested myopathy with myofibrillar disarray, and immunohistochemistry showed partial loss of desmin with some residual staining, while western blot analysis showed reduced desmin. RT-PCR of patient muscle RNA revealed two transcripts: a reduced normal desmin transcript and a larger abnormal transcript suggesting leaky splicing at the intron 5 donor site. Sequencing of the PCR products confirmed the inclusion of intron 5 in the longer transcript, predicted to cause a premature stop codon. Thus, we provide evidence for a leaky splice site causing partial loss of desmin associated with a unique phenotypic presentation of a milder form of desmin-related recessive myopathy overlapping with congenital myasthenic syndrome.

Jugular venous flow dynamics during acute weightlessness.

During spaceflight, fluids shift headward, causing internal jugular vein (IJV) distension and altered hemodynamics, including stasis and retrograde flow, that may increase the risk of thrombosis. This study's purpose was to determine the effects of acute exposure to weightlessness (0-G) on IJV dimensions and flow dynamics. We used two-dimensional (2-D) ultrasound to measure IJV cross-sectional area (CSA) and Doppler ultrasound to characterize venous blood flow patterns in the right and left IJV in 13 healthy participants (6 females) while 1) seated and supine on the ground, 2) supine during 0-G parabolic flight, and 3) supine during level flight (at 1-G). On Earth, in 1-G, moving from seated to supine posture increased CSA in both left (+62 [95% CI: +42 to 81] mm2, P < 0.0001) and right (+86 [95% CI: +58 to 113] mm2, P < 0.00012) IJV. Entry into 0-G further increased IJV CSA in both left (+27 [95% CI: +5 to 48] mm2, P = 0.02) and right (+30 [95% CI: +0.3 to 61] mm2, P = 0.02) relative to supine in 1-G. We observed stagnant flow in the left IJV of one participant during 0-G parabolic flight that remained during level flight but was not present during any imaging during preflight measures in the seated or supine postures; normal venous flow patterns were observed in the right IJV during all conditions in all participants. Alterations to cerebral outflow dynamics in the left IJV can occur during acute exposure to weightlessness and thus, may increase the risk of venous thrombosis during any duration of spaceflight.NEW & NOTEWORTHY The absence of hydrostatic pressure gradients in the vascular system and loss of tissue weight during weightlessness results in altered flow dynamics in the left internal jugular vein in some astronauts that may contribute to an increased risk of thromboembolism during spaceflight. Here, we report that the internal jugular veins distend bilaterally in healthy participants and that flow stasis can occur in the left internal jugular vein during acute weightlessness produced by parabolic flight.

Development of optic disc edema during 30 days of hypercapnic head-down tilt bed rest is associated with short sleep duration and blunted temperature amplitude.

Sleep and circadian temperature disturbances occur with spaceflight and may, in part, result from the chronically elevated carbon dioxide (CO2) levels on the international space station. Impaired sleep may contribute to decreased glymphatic clearance and, when combined with the chronic headward fluid shift during actual spaceflight or the spaceflight analog head-down tilt bed rest (HDTBR), may contribute to the development of optic disc edema. We determined if strict HDTBR combined with mildly elevated CO2 levels influenced sleep and core temperature and was associated with the development of optic disc edema. Healthy participants (5 females) aged 25-50 yr, underwent 30 days of strict 6° HDTBR with ambient Pco2 = 4 mmHg. Measures of sleep, 24-h core temperature, overnight transcutaneous CO2, and Frisén grade edema were made pre-HDTBR, on HDTBR days 4, 17, 28, and post-HDTBR days 4 and 10. During all HDTBR time points, sleep, core temperature, and overnight transcutaneous CO2 were not different than the pre-HDTBR measurements. However, independent of the HDTBR intervention, the odds ratios {mean [95% confidence interval (CI)]} for developing Frisén grade optic disc edema were statistically significant for each hour below the mean total sleep time (2.2 [1.1-4.4]) and stage 2 nonrapid eye movement (NREM) sleep (4.8 [1.3-18.6]), and above the mean for wake after sleep onset (3.6 [1.2-10.6]) and for each 0.1°C decrease in core temperature amplitude below the mean (4.0 [1.4-11.7]). These data suggest that optic disc edema occurring during HDTBR was more likely to occur in those with short sleep duration and/or blunted temperature amplitude.NEW & NOTEWORTHY We determined that sleep and 24-h core body temperature were unaltered by 30 days exposure to the spaceflight analog strict 6° head-down tilt bed rest (HDTBR) in a 0.5% CO2 environment. However, shorter sleep duration, greater wake after sleep onset, and lower core temperature amplitude present throughout the study were associated with the development of optic disc edema, a key finding of spaceflight-associated neuro-ocular syndrome.

Rare disease research workflow using multilayer networks elucidates the molecular determinants of severity in Congenital Myasthenic Syndromes.

Exploring the molecular basis of disease severity in rare disease scenarios is a challenging task provided the limitations on data availability. Causative genes have been described for Congenital Myasthenic Syndromes (CMS), a group of diverse minority neuromuscular junction (NMJ) disorders; yet a molecular explanation for the phenotypic severity differences remains unclear. Here, we present a workflow to explore the functional relationships between CMS causal genes and altered genes from each patient, based on multilayer network community detection analysis of complementary biomedical information provided by relevant data sources, namely protein-protein interactions, pathways and metabolomics. Our results show that CMS severity can be ascribed to the personalized impairment of extracellular matrix components and postsynaptic modulators of acetylcholine receptor (AChR) clustering. This work showcases how coupling multilayer network analysis with personalized -omics information provides molecular explanations to the varying severity of rare diseases; paving the way for sorting out similar cases in other rare diseases.

Mobile element insertions in rare diseases: a comparative benchmark and reanalysis of 60,000 exome samples.

Mobile element insertions (MEIs) are a known cause of genetic disease but have been underexplored due to technical limitations of genetic testing methods. Various bioinformatic tools have been developed to identify MEIs in Next Generation Sequencing data. However, most tools have been developed specifically for genome sequencing (GS) data rather than exome sequencing (ES) data, which remains more widely used for routine diagnostic testing. In this study, we benchmarked six MEI detection tools (ERVcaller, MELT, Mobster, SCRAMble, TEMP2 and xTea) on ES data and on GS data from publicly available genomic samples (HG002, NA12878). For all the tools we evaluated sensitivity and precision of different filtering strategies. Results show that there were substantial differences in tool performance between ES and GS data. MELT performed best with ES data and its combination with SCRAMble increased substantially the detection rate of MEIs. By applying both tools to 10,890 ES samples from Solve-RD and 52,624 samples from Radboudumc we were able to diagnose 10 patients who had remained undiagnosed by conventional ES analysis until now. Our study shows that MELT and SCRAMble can be used reliably to identify clinically relevant MEIs in ES data. This may lead to an additional diagnosis for 1 in 3000 to 4000 patients in routine clinical ES.

Ocular Deformations in Spaceflight-Associated Neuro-Ocular Syndrome and Idiopathic Intracranial Hypertension.

Purpose: Spaceflight-associated neuro-ocular syndrome (SANS) shares several clinical features with idiopathic intracranial-hypertension (IIH), namely disc edema, globe-flattening, hyperopia, and choroidal folds. Globe-flattening is caused by increased intracranial pressure (ICP) in IIH, but the cause in SANS is uncertain. If increased ICP alone causes SANS, then the ocular deformations should be similar to IIH; if not, alternative mechanisms would be implicated. Methods: Using optical coherence tomography (OCT) axial images of the optic nerve head, we compared "pre to post" ocular deformations in 22 patients with IIH to 25 crewmembers with SANS. We used two metrics to assess ocular deformations: displacements of Bruch's membrane opening (BMO-displacements) and Geometric Morphometrics to analyze peripapillary shape changes of Bruch's membrane layer (BML-shape). Results: We found a large disparity in the mean retinal nerve-fiber layer thickness between SANS (108 um; 95% confidence interval [CI] = 105-111 um) and IIH (300 um; 95% CI = 251-350.1 um). The pattern of BML-shape and BMO-displacements in SANS were significantly different from IIH (P < 0.0001). Deformations in IIH were large and preponderantly anterior, whereas the deformations in SANS were small and bidirectional. The degree of disc edema did not explain the differences in ocular deformations. Conclusions: This study showed substantial differences in the degree of disc edema and the pattern of ocular deformations between IIH and SANS. The precise cause for these differences is unknown but suggests that there may be fundamental differences in the underlying biomechanics of each consistent with the prevailing hypothesis that SANS is consequent to multiple factors beyond ICP alone. We propose a hypothetical model to explain the differences between IIH and SANS based on the pattern of indentation loads.

Remote visualization of large-scale genomic alignments for collaborative clinical research and diagnosis of rare diseases.

The Solve-RD project objectives include solving undiagnosed rare diseases (RD) through collaborative research on shared genome-phenome datasets. The RD-Connect Genome-Phenome Analysis Platform (GPAP), for data collation and analysis, and the European Genome-Phenome Archive (EGA), for file storage, are two key components of the Solve-RD infrastructure. Clinical researchers can identify candidate genetic variants within the RD-Connect GPAP and, thanks to the developments presented here as part of joint ELIXIR activities, are able to remotely visualize the corresponding alignments stored at the EGA. The Global Alliance for Genomics and Health (GA4GH) htsget streaming application programming interface (API) is used to retrieve alignment slices, which are rendered by an integrated genome viewer (IGV) instance embedded in the GPAP. As a result, it is no longer necessary for over 11,000 datasets to download large alignment files to visualize them locally. This work highlights the advantages, from both the user and infrastructure perspectives, of implementing interoperability standards for establishing federated genomics data networks.

Incidence and Progression of Chorioretinal Folds During Long-Duration Spaceflight.

Importance: The primary contributing factor for development of chorioretinal folds during spaceflight is unknown. Characterizing fold types that develop and tracking their progression may provide insight into the pathophysiology of spaceflight-associated neuro-ocular syndrome and elucidate the risk of fold progression for future exploration-class missions exceeding 12 months in duration. Objective: To determine the incidence and presentation of chorioretinal folds in long-duration International Space Station crew members and objectively quantify the progression of choroidal folds during spaceflight. Design, Setting, and Participants: In this retrospective cohort study, optical coherence tomography scans of the optic nerve head and macula of crew members completing long-duration spaceflight missions were obtained on Earth prior to spaceflight and during flight. A panel of experts examined the scans for the qualitative presence of chorioretinal folds. Peripapillary total retinal thickness was calculated to identify eyes with optic disc edema, and choroidal folds were quantified based on surface roughness within macular and peripapillary regions of interest. Interventions or Exposures: Spaceflight missions ranging 6 to 12 months. Main Outcomes and Measures: Incidence of peripapillary wrinkles, retinal folds, and choroidal folds; peripapillary total retinal thickness; and Bruch membrane surface roughness. Results: A total of 36 crew members were analyzed (mean [SD] age, 46 [6] years; 7 [19%] female). Chorioretinal folds were observed in 12 of 72 eyes (17%; 6 crew members). In eyes with early signs of disc edema, 10 of 42 (24%) had choroidal folds, 4 of 42 (10%) had inner retinal folds, and 2 of 42 (5%) had peripapillary wrinkles. Choroidal folds were observed in all eyes with retinal folds and peripapillary wrinkles. Macular choroidal folds developed in 7 of 12 eyes (4 of 6 crew members) with folds and progressed with mission duration; these folds extended into the fovea in 6 eyes. Circumpapillary choroidal folds developed predominantly superior, nasal, and inferior to the optic nerve head and increased in prevalence and severity with mission duration. Conclusions and Relevance: Choroidal folds were the most common fold type to develop during spaceflight; this differs from reports in idiopathic intracranial hypertension, suggesting differences in the mechanisms underlying fold formation. Quantitative measures demonstrate the development and progression of choroidal folds during weightlessness, and these metrics may help to assess the efficacy of spaceflight-associated neuro-ocular syndrome countermeasures.

MRI-based quantification of posterior ocular globe flattening during 60 days of strict 6° head-down tilt bed rest with and without daily centrifugation.

Spaceflight associated neuro-ocular syndrome (SANS) is associated with acquired optic disc edema, hyperopia, and posterior globe flattening in some astronauts during long-duration spaceflight possibly due to the headward fluid redistribution in microgravity. The goal of this study was to assess whether strict head-down tilt (HDT) bed rest as a spaceflight analog would produce globe flattening and whether centrifugation could prevent these changes. Twenty-four healthy subjects separated into three groups underwent 60 days of strict 6° HDT bed rest: one control group with no countermeasure (n = 8) and two countermeasure groups exposed to 30 min daily of short-arm centrifugation as a means of artificial gravity (AG), either intermittent (iAG, n = 8) or continuous (cAG, n = 8). Magnetic resonance images (MRI) were collected at baseline, HDT-day 14, HDT-day 52, and 3 days after bed rest. An automated method was applied to quantify posterior globe volume displacement compared with baseline scans. On average, subjects showed an increasing degree of globe volume displacement with bed rest duration (means ± SE: 1.41 ± 1.01 mm3 on HDT14 and 4.04 ± 1.19 mm3 on HDT52) that persisted post-bed rest (5.51 ± 1.26 mm3). Application of 30 min daily AG did not have a significant impact on globe volume displacement (P = 0.42 for cAG and P = 0.93 for iAG compared with control). These results indicate that strict 6° HDT bed rest produced displacement of the posterior globe with a trend of increasing displacement with longer duration that was not prevented by daily 30 min exposure to AG.NEW & NOTEWORTHY Head-down tilt (HDT) bed rest is commonly used as a spaceflight analog for investigating spaceflight associated neuro-ocular syndrome (SANS). Posterior ocular globe flattening has been identified in astronauts with SANS but until now has not been investigated during HDT bed rest. In this study, posterior ocular globe volume displacement was quantified before, during, and after HDT bed rest and countermeasures were tested for their potential to reduce the degree of globe flattening.

Identification of Factors Associated With the Development of Optic Disc Edema During Spaceflight.

Importance: Approximately 70% of crew members who complete long-duration missions to the International Space Station develop signs of optic disc edema, a hallmark finding of spaceflight-associated neuro-ocular syndrome. The onset and magnitude of edema differ across individuals, and the reason for this variability remains unknown. Identifying risk factors for spaceflight-induced disc edema is important because this condition may become more severe during extended-duration missions to the moon and Mars and could be associated with irreversible vision loss. Objective: To assess whether preflight indicators of crowded optic nerve head morphology, other ocular measures (such as choroid thickness and axial length), body weight, body mass index, sex, age, and previous flight experience are associated with optic disc edema development. Design, Setting, and Participants: This cohort study analyzed ocular, body weight, and demographic data collected from 31 US and international crew members before, during, and after spaceflight at the NASA Johnson Space Center and International Space Station. Ocular factors assessed included preflight and in-flight peripapillary total retinal thickness, minimum rim width, optic cup volume, mean cup depth, mean cup width, cup-disc ratio, Bruch membrane opening area, retinal nerve fiber layer thickness, choroid thickness, axial length, and refractive error. In addition, body weight, body mass index, sex, age, and previous spaceflight experience were assessed for associations with optic disc edema development. The data were analyzed from August 2021 to June 2022. Exposure: Approximately 6 to 12 months of spaceflight. Main Outcomes and Measures: In-flight increases in peripapillary total retinal thickness. Linear mixed models were used to assess for associations between a wide range of risk factors and in-flight increases in peripapillary total retinal thickness, which is a sensitive objective measure for detecting optic disc edema. Results: This study included 31 International Space Station crew members with a mean (SD) age of 46.9 (6.0) years (25 men [80.6%]). During spaceflight, mean (SE) peripapillary total retinal thickness increased from 392.0 (5.8) µm to 430.2 (9.6) µm (P < .001), and greater individual changes were associated with smaller preflight cup volume (slope [SE], -62.8 [18.9]; P = .002), shallower preflight cup depth (slope [SE], -0.11 [0.03]; P < .001), and narrower preflight cup width (slope [SE], -0.03 [0.01]; P = .03). No associations were observed between changes in peripapillary total retinal thickness and any other variable evaluated. Conclusions and Relevance: Findings of this cohort study suggest that smaller optic cup morphology may be associated with optic disc edema development during spaceflight. Crew members with this cup profile may benefit from enhanced ophthalmic monitoring during spaceflight and use of countermeasures against spaceflight-associated neuro-ocular syndrome.

Noninvasive indicators of intracranial pressure before, during, and after long-duration spaceflight.

Weightlessness induces a cephalad shift of blood and cerebrospinal fluid that may increase intracranial pressure (ICP) during spaceflight, whereas lower body negative pressure (LBNP) may provide an opportunity to caudally redistribute fluids and lower ICP. To investigate the effects of spaceflight and LBNP on noninvasive indicators of ICP (nICP), we studied 13 crewmembers before and after spaceflight in seated, supine, and 15° head-down tilt postures, and at ∼45 and ∼150 days of spaceflight with and without 25 mmHg LBNP. We used four techniques to quantify nICP: cerebral and cochlear fluid pressure (CCFP), otoacoustic emissions (OAE), ultrasound measures of optic nerve sheath diameter (ONSD), and ultrasound-based internal jugular vein pressure (IJVp). On flight day 45, two nICP measures were lower than preflight supine posture [CCFP: mean difference -98.5 -nL (CI: -190.8 to -6.1 -nL), P = 0.037]; [OAE: -19.7° (CI: -10.4° to -29.1°), P < 0.001], but not significantly different from preflight seated measures. Conversely, ONSD was not different than any preflight posture, whereas IJVp was significantly greater than preflight seated measures [14.3 mmHg (CI: 10.1 to 18.5 mmHg), P < 0.001], but not significantly different than preflight supine measures. During spaceflight, acute LBNP application did not cause a significant change in nICP indicators. These data suggest that during spaceflight, nICP is not elevated above values observed in the seated posture on Earth. Invasive measures would be needed to provide absolute ICP values and more precise indications of ICP change during various phases of spaceflight.NEW & NOTEWORTHY The current study provides new evidence that intracranial pressure (ICP), as assessed with noninvasive measures, may not be elevated during long-duration spaceflight. In addition, the acute use of lower body negative pressure did not significantly reduce indicators of ICP during weightlessness.

Changes in Optic Nerve Head and Retinal Morphology During Spaceflight and Acute Fluid Shift Reversal.

Importance: Countermeasures that reverse the headward fluid shift experienced in weightlessness have the potential to mitigate spaceflight-associated neuro-ocular syndrome. This study investigated whether use of the countermeasure lower-body negative pressure during spaceflight was associated with changes in ocular structure. Objective: To determine whether changes to the optic nerve head and retina during spaceflight can be mitigated by brief in-flight application of 25-mm Hg lower-body negative pressure. Design, Setting, and Participants: In the National Aeronautics and Space Administration's "Fluid Shifts Study," a prospective cohort study, optical coherence tomography scans of the optic nerve head and macula were obtained from US and international crew members before flight, in-flight, and up to 180 days after return to Earth. In-flight scans were obtained both under normal weightless conditions and 10 to 20 minutes into lower-body negative pressure exposure. Preflight and postflight data were collected in the seated, supine, and head-down tilt postures. Crew members completed 6- to 12-month missions that took place on the International Space Station. Data were analyzed from 2016 to 2021. Interventions or Exposures: Spaceflight and lower-body negative pressure. Main Outcomes and Measures: Changes in minimum rim width, optic cup volume, Bruch membrane opening height, peripapillary total retinal thickness, and macular thickness. Results: Mean (SD) flight duration for the 14 crew members (mean [SD] age, 45 [6] years; 11 male crew members [79%]) was 214 (72) days. Ocular changes on flight day 150, as compared with preflight seated, included an increase in minimum rim width (33.8 µm; 95% CI, 27.9-39.7 µm; P < .001), decrease in cup volume (0.038 mm3; 95% CI, 0.030-0.046 mm3; P < .001), posterior displacement of Bruch membrane opening (-9.0 µm; 95% CI, -15.7 to -2.2 µm; P = .009), and decrease in macular thickness (fovea to 500 µm, 5.1 µm; 95% CI, 3.5-6.8 µm; P < .001). Brief exposure to lower-body negative pressure did not affect these parameters. Conclusions and Relevance: Results of this cohort study suggest that peripapillary tissue thickening, decreased cup volume, and mild central macular thinning were associated with long-duration spaceflight. Acute exposure to 25-mm Hg lower-body negative pressure did not alter optic nerve head or retinal morphology, suggesting that longer durations of a fluid shift reversal may be needed to mitigate spaceflight-induced changes and/or other factors are involved.

Systematic Collaborative Reanalysis of Genomic Data Improves Diagnostic Yield in Neurologic Rare Diseases.

Many patients experiencing a rare disease remain undiagnosed even after genomic testing. Reanalysis of existing genomic data has shown to increase diagnostic yield, although there are few systematic and comprehensive reanalysis efforts that enable collaborative interpretation and future reinterpretation. The Undiagnosed Rare Disease Program of Catalonia project collated previously inconclusive good quality genomic data (panels, exomes, and genomes) and standardized phenotypic profiles from 323 families (543 individuals) with a neurologic rare disease. The data were reanalyzed systematically to identify relatedness, runs of homozygosity, consanguinity, single-nucleotide variants, insertions and deletions, and copy number variants. Data were shared and collaboratively interpreted within the consortium through a customized Genome-Phenome Analysis Platform, which also enables future data reinterpretation. Reanalysis of existing genomic data provided a diagnosis for 20.7% of the patients, including 1.8% diagnosed after the generation of additional genomic data to identify a second pathogenic heterozygous variant. Diagnostic rate was significantly higher for family-based exome/genome reanalysis compared with singleton panels. Most new diagnoses were attributable to recent gene-disease associations (50.8%), additional or improved bioinformatic analysis (19.7%), and standardized phenotyping data integrated within the Undiagnosed Rare Disease Program of Catalonia Genome-Phenome Analysis Platform functionalities (18%).