Brief Report: Evaluating the Diagnostic Yield of Commercial Gene Panels in Autism

Autism is a prevalent neurodevelopmental condition, highly heterogenous in both genotype and phenotype. This communication adds to existing discussion of the heterogeneity of clinical sequencing tests, “gene panels”, marketed for application in autism. We evaluate the clinical utility of available gene panels based on existing genetic evidence. We determine that diagnostic yields of these gene panels range from 0.22% to 10.02% and gene selection for the panels is variable in relevance, here measured as percentage overlap with SFARI Gene and ranging from 15.15% to 100%. We conclude that gene panels marketed for use in autism are currently of limited clinical utility, and that sequencing with greater coverage may be more appropriate.

MicroSEC filters sequence errors for formalin-fixed and paraffin-embedded samples

The clinical sequencing of tumors is usually performed on formalin-fixed, paraffin-embedded samples and results in many sequencing errors. We identified that most of these errors are detected in chimeric reads caused by single-strand DNA molecules with microhomology. During the end-repair step of library preparation, mutations are introduced by the mis-annealing of two single-strand DNA molecules comprising homologous sequences. The mutated bases are distributed unevenly near the ends in the individual reads. Our filtering pipeline, MicroSEC, focuses on the uneven distribution of mutations in each read and removes the sequencing errors in formalin-fixed, paraffin-embedded samples without over-eliminating the mutations detected also in fresh frozen samples. Amplicon-based sequencing using 97 mutations confirmed that the sensitivity and specificity of MicroSEC were 97% (95% confidence interval: 82–100%) and 96% (95% confidence interval: 88–99%), respectively. Our pipeline will increase the reliability of the clinical sequencing and advance the cancer research using formalin-fixed, paraffin-embedded samples.

Variant abundance estimation for SARS-CoV-2 in wastewater using RNA-Seq quantification

Effectively monitoring the spread of SARS-CoV-2 variants is essential to efforts to counter the ongoing pandemic. Wastewater monitoring of SARS-CoV-2 RNA has proven an effective and efficient technique to approximate COVID-19 case rates in the population. Predicting variant abundances from wastewater, however, is technically challenging. Here we show that by sequencing SARS-CoV-2 RNA in wastewater and applying computational techniques initially used for RNA-Seq quantification, we can estimate the abundance of variants in wastewater samples. We show by sequencing samples from wastewater and clinical isolates in Connecticut U.S.A. between January and April 2021 that the temporal dynamics of variant strains broadly correspond. We further show that this technique can be used with other wastewater sequencing techniques by expanding to samples taken across the United States in a similar timeframe. We find high variability in signal among individual samples, and limited ability to detect the presence of variants with clinical frequencies <10%; nevertheless, the overall trends match what we observed from sequencing clinical samples. Thus, while clinical sequencing remains a more sensitive technique for population surveillance, wastewater sequencing can be used to monitor trends in variant prevalence in situations where clinical sequencing is unavailable or impractical.

Creating accessible Spanish language materials for Clinical Sequencing Evidence-Generating Research consortium genomic projects: challenges and lessons learned

Aim: To increase Spanish speakers' representation in genomics research, accessible study materials on genetic topics must be made available in Spanish. Materials & methods: The Clinical Sequencing Evidence-Generating Research consortium is evaluating genome sequencing for underserved populations. All sites needed Spanish translation of recruitment materials, surveys and return of results. Results: We describe our process for translating site-specific materials, as well as shared measures across sites, to inform future efforts to engage Spanish speakers in research. Conclusion: In translating and adapting study materials for roughly 1000 Spanish speakers across the USA, and harmonizing translated measures across diverse sites, we overcame numerous challenges. Translation should be performed by professionals. Studies must allocate sufficient time, effort and budget to translate and adapt participant materials.

Implementation of clinical sequencing for molecular profiling in patients with advanced cancer

BACKGROUND: The advancement of cancer genomics has allowed for multiplex gene assays using next-generation sequencing (NGS) to be practically implemented, however, a clinical practice system remains to be established. OBJECTIVE: We evaluated the feasibility of clinical sequencing using NGS-based multiplex gene assays between cooperating medical institutions in patients with advanced cancers. METHODS: In this observational study, DNA and RNA samples prepared from existing tumor tissues were subjected to comprehensive genomic profiling using targeted sequencing. RESULTS: From January 2017 to March 2019, 36 samples from 33 patients were assessed. Of all patients, 27 (82%) had lung cancer, with the median age of 50 years (range 38–83). Multiplex gene panel tests were successfully carried out on 35/36 (97%) samples. Potentially actionable gene alterations were identified in 10/30 (33%) samples (3 HER2, 2 KRAS, 2 ALK, 1 PIK3CA, 1 RET, and 1 CDKN2A). In the 6 samples examined for resistant mechanisms, ALK I1171N mutation and MET copy number gain were detected in 2 patients with ALK rearrangement-positive lung cancer. CONCLUSIONS: Clinical sequencing using NGS-based multiplex gene assays between collaborating domestic medical institutions was feasible, with a success rate of > 97%. Overall, clinical sequencing benefits therapeutic decision-making in patients with advanced cancer.