OBJECTIVE: Rare genetic variants in the PURA gene cause the PURA-related neurodevelopmental disorder (PURA-NDD), characterized by neonatal abnormalities and developmental delay. Using genome-wide DNA methylation analysis on patients with PURA variants, we aim to establish a PURA-NDD-specific methylation profile and provide further insights on the molecular basis of the PURA-NDD.
METHODS: Twenty three individuals (including 12 unpublished) carrying PURA variants were enrolled. We conducted the Illumina Infinium EPIC microarray analysis in 17 PURA-NDD individuals. In vitro experiments were performed to examine how PURA variants affect Pur-a expression.
RESULTS: Additional phenotypes in 12 newly identified patients were described in this study. Genome-wide DNA methylation analysis unveiled distinctive methylation profiles to PURA-NDD, and the established classifier can reclassify PURA variants of uncertain significance. Patients bearing PURA hapoloinsufficient and missense variants have comparable DNA methylation profiles, and cells expressing these PURA variants showed consistent Pur-a downregulation, suggesting a haploinsufficiency mechanism.
CONCLUSIONS: Patients with PURA-NDD exhibit a specific episignature, which has potential to aid identification and diagnosis of PURA-NDD patients and offer implications for further functional investigations.

Interpretation of disease-causing genetic variants remains a challenge in human genetics. Current costs and complexity of deep mutational scanning methods hamper crowd-sourcing approaches toward genome-wide resolution of variants in disease-related genes. Our framework, Saturation Mutagenesis-Reinforced Functional assays (SMuRF), addresses these issues by offering simple and cost-effective saturation mutagenesis, as well as streamlining functional assays to enhance the interpretation of unresolved variants. Applying SMuRF to neuromuscular disease genes FKRP and LARGE1, we generated functional scores for all possible coding single nucleotide variants, which aid in resolving clinically reported variants of uncertain significance. SMuRF also demonstrates utility in predicting disease severity, resolving critical structural regions, and providing training datasets for the development of computational predictors. Our approach opens new directions for enabling variant-to-function insights for disease genes in a manner that is broadly useful for crowd-sourcing implementation across standard research laboratories.

UNASSIGNED: Emerging evidence has suggested that inherited factors are also involved in lung cancer development. However, most studies focused on well-elucidated cancer predisposition genes, the majority of which are tumor suppressor genes. The profile of germline mutations in oncogenic driver genes remains unrevealed, which might also provide potential clinical implications for lung cancer management.
UNASSIGNED: Sequencing data from 36,813 unselected lung cancer patients who underwent somatic mutation profiling were retrospectively reviewed. All recruited patients had matched white blood cell samples sequenced in parallel using a capture-based panel including eight key lung cancer driver genes (epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), MET proto-oncogene, receptor tyrosine kinase (MET), Kirsten rat sarcoma viral oncogene homolog (KRAS), Erb-B2 receptor tyrosine kinase 2(ERBB2), ROS proto-oncogene 1, receptor tyrosine kinase (ROS1), ret proto-oncogene (RET), and B-Raf proto-oncogene, serine/threonine kinase (BRAF)). Likely pathogenic/pathogenic (LP/P) variants were called according to the classification criteria of the American College of Medical Genetics and Genomics. Variants of uncertain significance (VUS) located in the kinase domains of driver genes and occurring recurrently (n ≥3) were also included for further analyses.
UNASSIGNED: Seven different LP/P variants in EGFR, MET, or RET were identified in 0.03% of lung cancer patients (n = 14) and 25 different VUS in the kinase domains of seven driver genes (except KRAS) were found with a prevalence of 0.3% (n = 117).Collectively, germline mutations were most frequently seen in ROS1 (n = 31, 0.084%), followed by MET (n = 23, 0.062%), EGFR (n = 22, 0.06%), ALK (n = 22, 0.06%) and RET (n = 17, 0.046%). LP/P variants and VUS fell the most commonly in EGFR (n = 10, 72%) and ROS1 (n = 31, 26%), respectively. Of the 10 patients with EGFR LP/P germline mutation, 70% also acquired somatic EGFR driver mutation exon21 p.L858R or exon19 deletion at baseline; while the three patients with pathogenic germline RET mutation displayed distinct baseline somatic profiles of rare EGFR mutation or KRAS exon2 p.G12C. We discovered 11 germline mutations that also occurred somatically, including four LP/P variants and seven VUS.
UNASSIGNED: We present the first study to systemically characterize the germline mutation in oncogenic driver genes in a large cohort of unselected patients with lung cancers.

Characterizing the pathogenicity of BRCA1 variants of uncertain significance (VUSs) is a major bottleneck in clinical management of BRCA1-associated breast cancer. Saturation genome editing (SGE) was recently reported as an innovative laboratory-based approach to assess the pathogenicity of BRCA1 variants. We combined clinical phenotypes and SGE score to identify the pathogenicity of BRCA1 VUSs detected in a cohort of 8,085 breast cancer patients. According to SGE function score, 33 out of 144 BRCA1 VUSs detected were classified into \"loss of function\" (n = 13), \"intermediate\" (n = 2), and \"functional\" (n = 18) groups. Compared with non-carriers, \"loss of function\" VUS carriers (n = 19) presented significantly worse clinicopathological characteristics. These included younger age at breast cancer diagnosis (44.4 years vs. 51.2 years, P = 0.01), stronger family history of any cancer (57.9% vs. 32.3%, P = 0.017) especially breast or ovarian cancer (47.4% vs. 9.3%, P < 0.001), more bilateral breast cancer (31.6% vs. 3.4%, P < 0.001), and triple-negative breast cancer (47.4% vs. 12.8%, P < 0.001), which were comparable to those of pathogenic variant carriers. In contrast, the clinical phenotypes of \"functional\" VUS carriers were similar to those of non-carriers. These results indicated that SGE was a reliable method in BRCA1 variant classification. Combining SGE function score and the available evidence, twelve out of 33 BRCA1 VUSs were reclassified as pathogenic or likely pathogenic variants and one was benign.

The functional consequences of cancer-associated missense mutations are unclear for the majority of proteins. We have previously demonstrated that the activity of SOX and Pit-Oct-Unc (POU) family factors during pluripotency reprogramming can be switched and enhanced with rationally placed point mutations. Here, we interrogated cancer mutation databases and identified recurrently mutated positions at critical structural interfaces of the DNA-binding domains of paralogous SOX and POU family transcription factors. Using the conversion of mouse embryonic fibroblasts to induced pluripotent stem cells as functional readout, we identified several gain-of-function mutations that enhance pluripotency reprogramming by SOX2 and OCT4. Wild-type SOX17 cannot support reprogramming but the recurrent missense mutation SOX17-V118M is capable of inducing pluripotency. Furthermore, SOX17-V118M promotes oncogenic transformation, enhances thermostability and elevates cellular protein levels of SOX17. We conclude that the mutational profile of SOX and POU family factors in cancer can guide the design of high-performance reprogramming factors. Furthermore, we propose cellular reprogramming as a suitable assay to study the functional impact of cancer-associated mutations.

Next-generation sequencing is emerging as a viable alternative to chromosome microarray analysis for the diagnosis of chromosome disease syndromes. One next-generation sequencing methodology, copy number variation sequencing, has been shown to deliver high reliability, accuracy, and reproducibility for detection of fetal copy number variations in prenatal samples. However, its clinical utility as a first-tier diagnostic method has yet to be demonstrated in a large cohort of pregnant women referred for fetal chromosome testing.
We sought to evaluate copy number variation sequencing as a first-tier diagnostic method for detection of fetal chromosome anomalies in a general population of pregnant women with high-risk prenatal indications.
This was a prospective analysis of 3429 pregnant women referred for amniocentesis and fetal chromosome testing for different risk indications, including advanced maternal age, high-risk maternal serum screening, and positivity for an ultrasound soft marker. Amniocentesis was performed by standard procedures. Amniocyte DNA was analyzed by copy number variation sequencing with a chromosome resolution of 0.1 Mb. Fetal chromosome anomalies including whole chromosome aneuploidy and segmental imbalances were independently confirmed by gold standard cytogenetic and molecular methods and their pathogenicity determined following guidelines of the American College of Medical Genetics for sequence variants.
Clear interpretable copy number variation sequencing results were obtained for all 3429 amniocentesis samples. Copy number variation sequencing identified 3293 samples (96%) with a normal molecular karyotype and 136 samples (4%) with an altered molecular karyotype. A total of 146 fetal chromosome anomalies were detected, comprising 46 whole chromosome aneuploidies (pathogenic), 29 submicroscopic microdeletions/microduplications with known or suspected associations with chromosome disease syndromes (pathogenic), 22 other microdeletions/microduplications (likely pathogenic), and 49 variants of uncertain significance. Overall, the cumulative frequency of pathogenic/likely pathogenic and variants of uncertain significance chromosome anomalies in the patient cohort was 2.83% and 1.43%, respectively. In the 3 high-risk advanced maternal age, high-risk maternal serum screening, and ultrasound soft marker groups, the most common whole chromosome aneuploidy detected was trisomy 21, followed by sex chromosome aneuploidies, trisomy 18, and trisomy 13. Across all clinical indications, there was a similar incidence of submicroscopic copy number variations, with approximately equal proportions of pathogenic/likely pathogenic and variants of uncertain significance copy number variations. If karyotyping had been used as an alternate cytogenetics detection method, copy number variation sequencing would have returned a 1% higher yield of pathogenic or likely pathogenic copy number variations.
In a large prospective clinical study, copy number variation sequencing delivered high reliability and accuracy for identifying clinically significant fetal anomalies in prenatal samples. Based on key performance criteria, copy number variation sequencing appears to be a well-suited methodology for first-tier diagnosis of pregnant women in the general population at risk of having a suspected fetal chromosome abnormality.