International policies guiding the selection, analysis, and clinical management of secondary findings from genomic sequencing: A systematic review.

Secondary findings (SFs) from genomic sequencing can have significant impacts on patient health, yet existing practices guiding their clinical investigation are inconsistent. We systematically reviewed existing SFs policies to identify variations and gaps in guidance. We cataloged and appraised international policies from academic databases (n = 5, inception-02/2022) and international human genetic societies (n = 64; inception-05/2022), across the continuum of SFs selection, analysis, and clinical management. We assessed quality using AGREE-II and interpreted results using qualitative description. Of the 63 SFs policies identified, most pertained to clinical management of SFs (98%; n = 62; primarily consent and disclosure), some guided SFs analysis (60%; n = 38), while fewer mentioned SFs selection (48%; n = 30). Overall, policies recommend (1) identifying clinically actionable, pathogenic variants with high positive predictive values for disease (selection), (2) bioinformatically filtering variants using evidence-informed gene lists (analysis), and (3) discussing with affected individuals the SFs identified, their penetrance, expressivity, medical implications, and management (clinical management). Best practices for SFs variant analysis, clinical validation, and follow-up (i.e., surveillance, treatment, etc.) were minimally described. Upon quality assessment, policies were highly rated for scope and clarity (median score, 69) but were limited by their rigor and applicability (median scores, 27 and 25). Our review represents a comprehensive international synthesis of policy guiding SFs across the continuum of selection, analysis, and clinical management. Our synthesis will help providers navigate critical decision points in SFs investigation, although significant work is needed to address gaps in SFs analysis, clinical validation, and follow-up processes and to support evidence-based practice.

The mesencephalic locomotor region recruits V2a reticulospinal neurons to drive forward locomotion in larval zebrafish.

The mesencephalic locomotor region (MLR) is a brain stem area whose stimulation triggers graded forward locomotion. How MLR neurons recruit downstream vsx2+ (V2a) reticulospinal neurons (RSNs) is poorly understood. Here, to overcome this challenge, we uncovered the locus of MLR in transparent larval zebrafish and show that the MLR locus is distinct from the nucleus of the medial longitudinal fasciculus. MLR stimulations reliably elicit forward locomotion of controlled duration and frequency. MLR neurons recruit V2a RSNs via projections onto somata in pontine and retropontine areas, and onto dendrites in the medulla. High-speed volumetric imaging of neuronal activity reveals that strongly MLR-coupled RSNs are active for steering or forward swimming, whereas weakly MLR-coupled medullary RSNs encode the duration and frequency of the forward component. Our study demonstrates how MLR neurons recruit specific V2a RSNs to control the kinematics of forward locomotion and suggests conservation of the motor functions of V2a RSNs across vertebrates.

From the patient to the population: Use of genomics for population screening.

Genomic medicine is expanding from a focus on diagnosis at the patient level to prevention at the population level given the ongoing under-ascertainment of high-risk and actionable genetic conditions using current strategies, particularly hereditary breast and ovarian cancer (HBOC), Lynch Syndrome (LS) and familial hypercholesterolemia (FH). The availability of large-scale next-generation sequencing strategies and preventive options for these conditions makes it increasingly feasible to screen pre-symptomatic individuals through public health-based approaches, rather than restricting testing to high-risk groups. This raises anew, and with urgency, questions about the limits of screening as well as the moral authority and capacity to screen for genetic conditions at a population level. We aimed to answer some of these critical questions by using the WHO Wilson and Jungner criteria to guide a synthesis of current evidence on population genomic screening for HBOC, LS, and FH.

Genomic architecture of autism from comprehensive whole-genome sequence annotation.

Fully understanding autism spectrum disorder (ASD) genetics requires whole-genome sequencing (WGS). We present the latest release of the Autism Speaks MSSNG resource, which includes WGS data from 5,100 individuals with ASD and 6,212 non-ASD parents and siblings (total n = 11,312). Examining a wide variety of genetic variants in MSSNG and the Simons Simplex Collection (SSC; n = 9,205), we identified ASD-associated rare variants in 718/5,100 individuals with ASD from MSSNG (14.1%) and 350/2,419 from SSC (14.5%). Considering genomic architecture, 52% were nuclear sequence-level variants, 46% were nuclear structural variants (including copy-number variants, inversions, large insertions, uniparental isodisomies, and tandem repeat expansions), and 2% were mitochondrial variants. Our study provides a guidebook for exploring genotype-phenotype correlations in families who carry ASD-associated rare variants and serves as an entry point to the expanded studies required to dissect the etiology in the ∼85% of the ASD population that remain idiopathic.