Germline Genome Research Articles

MITE infestation accommodated by genome editing in the germline genome of the ciliate Blepharisma

During their development following sexual conjugation, ciliates excise numerous internal eliminated sequences (IESs) from a copy of the germline genome to produce the functional somatic genome. Most IESs are thought to have originated from transposons, but the presumed homology is often obscured by sequence decay. To obtain more representative perspectives on the nature of IESs and ciliate genome editing, we assembled 40,000 IESs of Blepharisma stoltei, a species belonging to a lineage (Heterotrichea) that diverged early from those of the intensively studied model ciliate species. About a quarter of IESs were short (<115 bp), largely nonrepetitive, and with a pronounced ~10 bp periodicity in length; the remainder were longer (up to 7 kbp) and nonperiodic and contained abundant interspersed repeats. Contrary to the expectation from current models, the assembled Blepharisma germline genome encodes few transposases. Instead, its most abundant repeat (8,000 copies) is a Miniature Inverted-repeat Transposable Element (MITE), apparently a deletion derivative of a germline-limited Pogo-family transposon. We hypothesize that MITEs are an important source of IESs whose proliferation is eventually self-limiting and that rather than defending the germline genomes against mobile elements, transposase domestication actually facilitates the accumulation of junk DNA.

Origins of genome-editing excisases as illuminated by the somatic genome of the ciliate Blepharisma

Massive DNA excision occurs regularly in ciliates, ubiquitous microbial eukaryotes with somatic and germline nuclei in the same cell. Tens of thousands of internally eliminated sequences (IESs) scattered throughout the ciliate germline genome are deleted during the development of the streamlined somatic genome. The genus Blepharisma represents one of the two high-level ciliate clades (subphylum Postciliodesmatophora) and, unusually, has dual pathways of somatic nuclear and genome development. This makes it ideal for investigating the functioning and evolution of these processes. Here we report the somatic genome assembly ofBlepharismastoltei strain ATCC 30299 (41 Mbp), arranged as numerous telomere-capped minichromosomal isoforms. This genome encodes eight PiggyBac transposase homologs no longer harbored by transposons. All appear subject to purifying selection, but just one, the putative IES excisase, has a complete catalytic triad. We hypothesize that PiggyBac homologs were ancestral excisases that enabled the evolution of extensive natural genome editing.

N-terminal domain influences steroid activation of the Atlantic sea lamprey corticoid receptor

Lampreys are jawless fish that evolved about 550 million years ago at the base of the vertebrate line. Modern lampreys contain a corticoid receptor (CR), the common ancestor of the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), which first appear in cartilaginous fish, such as sharks. Until recently, 344 amino acids at the amino terminus of adult lamprey CR were not present in the lamprey CR sequence in GenBank. A search of the recently sequenced lamprey germline genome identified two CR sequences, CR1 and CR2, containing the 344 previously un-identified amino acids. CR1 also contains a novel four amino acid insertion in the DNA-binding domain (DBD). We studied corticosteroid and progesterone activation of CR1 and CR2 and found their strongest response was to 11-deoxycorticosterone and 11-deoxycortisol, the two circulating corticosteroids in lamprey. Based on steroid specificity, both CRs are close to elephant shark MR and distant from elephant shark GR. HEK293 cells that were transfected with full-length CR1 or CR2 and the MMTV promoter have about 3-fold higher steroid-mediated activation compared to HEK293 cells transfected with these CRs and the TAT3 promoter. Deletion of the amino-terminal domain (NTD) of lamprey CR1 and CR2 to form truncated CRs decreased transcriptional activation by about 70% in HEK293 cells that were transfected with MMTV, but increased transcription by about 6-fold in cells transfected with TAT3. This indicated that the promoter has an important effect on NTD regulation of transcriptional activation of the CR by steroids. Our results also indicate that the entire lamprey CR sequence is needed for an accurate determination of steroid-mediated transcription.

Ethics of Germline Genome Editing (GGE) for Therapeutics

Ethics of Germline Genome Editing (GGE) for Therapeutics

Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri

In the Japanese hagfish Eptatretus burgeri, 16 chromosomes (eliminated [E]-chromosomes) have been lost in somatic cells (2n = 36), which is equivalent to approx. 21% of the genomic DNA in germ cells (2n = 52). At least seven of the 12 eliminated repetitive DNA families isolated in eight hagfish species were selectively amplified in the germline genome of this species. One of them, EEEb1 (eliminated element of E.burgeri 1) is exclusively localized on all E-chromosomes. Herein, we identified four novel eliminated repetitive DNA families (named EEEb3-6) through PCR amplification and suppressive subtractive hybridization (SSH) combined with Southern-blot hybridization. EEEb3 was mosaic for 5S rDNA and SINE elements. EEEb4 was GC-rich repeats and has one pair of direct and inverted repeats, whereas EEEb5 and EEEb6 were AT-rich repeats with one pair and two pairs of sub-repeats, respectively. Interestingly, all repeat classes except EEEb3 were transcribed in the testes, although no open reading frames (ORF) were identified. We conducted fluorescence in situ hybridization (FISH) to examine the chromosomal localizations of EEEb3-6 and EEEb2, which was previously isolated from the germline genome of E. burgeri. All sequences were only found on all EEEb1-positive E-chromosomes. Copy number estimation of the repeated elements by slot-blot hybridization revealed that (i) the EEEb1-6 family members occupied 39.9% of the total eliminated DNA, and (ii) a small number of repeats were retained in somatic cells, suggesting that there is incomplete elimination of the repeated elements. These results provide new insights into the mechanisms involved in the chromosome elimination and the evolution of E-chromosomes.

Comparative genomics reveals insight into the evolutionary origin of massively scrambled genomes.

Ciliates are microbial eukaryotes that undergo extensive programmed genome rearrangement, a natural genome editing process that converts long germline chromosomes into smaller gene-rich somatic chromosomes. Three well-studied ciliates include Oxytricha trifallax, Tetrahymena thermophila, and Paramecium tetraurelia, but only the Oxytricha lineage has a massively scrambled genome, whose assembly during development requires hundreds of thousands of precisely programmed DNA joining events, representing the most complex genome dynamics of any known organism. Here we study the emergence of such complex genomes by examining the origin and evolution of discontinuous and scrambled genes in the Oxytricha lineage. This study compares six genomes from three species, the germline and somatic genomes for Euplotes woodruffi, Tetmemena sp., and the model ciliate O. trifallax. We sequenced, assembled, and annotated the germline and somatic genomes of E. woodruffi, which provides an outgroup, and the germline genome of Tetmemena sp. We find that the germline genome of Tetmemena is as massively scrambled and interrupted as Oxytricha's: 13.6% of its gene loci require programmed translocations and/or inversions, with some genes requiring hundreds of precise gene editing events during development. This study revealed that the earlier diverged spirotrich, E. woodruffi, also has a scrambled genome, but only roughly half as many loci (7.3%) are scrambled. Furthermore, its scrambled genes are less complex, together supporting the position of Euplotes as a possible evolutionary intermediate in this lineage, in the process of accumulating complex evolutionary genome rearrangements, all of which require extensive repair to assemble functional coding regions. Comparative analysis also reveals that scrambled loci are often associated with local duplications, supporting a gradual model for the origin of complex, scrambled genomes via many small events of DNA duplication and decay.

Initial heritable genome editing: mapping a responsible pathway from basic research to the clinic

Following the Second Summit on Human Gene Editing in Hong Kong in 2018, where the birth of two girls with germline genome editing was revealed, the need for a responsible pathway to the clinical application of human germline genome editing has been repeatedly emphasised. This paper aims to contribute to the ongoing discussion on research ethics issues in germline genome editing by exploring key issues related to the initial applications of CRISPR in reproductive medicine. Following an overview of the current discussion on bringing germline genome editing into clinical practice, we outline the specific challenges associated with such interventions and the features that distinguish them from conventional clinical testing of new medical treatments. We then review proposed ethical requirements for initial heritable genome editing, such as the absence of reasonable alternatives, the existence of sufficient and reliable preclinical data, appropriate informed consent, requirements related to safety, and long-term follow-up.

Germline Variants in MDM4 Cause a Disorder of p53 Dysregulation and Insufficient Telomere Maintenance

Introduction: Telomere biology disorders (TBD) comprise a group of hereditary disorders characterized by a genetically determined insufficiency of telomere maintenance leading to fibrosis and malfunction, especially of bone marrow (BM), liver, and lungs. TBD can present with highly variable phenotype as so-called "cryptic" forms with only mild clinical manifestations. Known genetic causes include defects in genes encoding mainly for proteins directly involved in telomere biology. However, today, still a relevant subgroup of patients with the clinical picture of TBD remain without a molecular diagnosis. Recently, members of yet a single family carrying a dominantly inherited missense variant in MDM4 (NM_002393.5:c.1361C>T, p.(Thr454Met)) with premature telomere length (TL) shortening were reported (Toufektchan et al., 2020) presenting with a phenotype similar to the classical TBD, Dyskeratosis congenita. The MDM4-gene encodes a 490-amino acid protein that interacts with and negatively regulates p53. In vitro and murine studies suggested a loss of p53 regulation by the defective MDM4 protein leading to augmented p53 activity and insufficient telomere maintenance. In line with this finding, mice with an overactive TRP53 developed BM failure and lung fibrosis resembling the phenotype of TBD. Here, we report three patients from different families carrying germline variants in MDM4 presenting with a TBD phenotype of varying severity. Methods: All patients were included in the Aachen Telomere Registry (ATR). Informed consent for genetic analyses was obtained from all participants. All patients received analysis of TL via flow-FISH and genetic work-up using whole exome sequencing (WES). Results: Patient 1 is a newborn boy with uncomplicated delivery. At 4 weeks of age, the patient presented jaundice and a routine blood sample was taken. Clinical examination showed no abnormalities. Blood counts showed neutropenia with 500/µl and normal hemoglobin and platelet counts. WES revealed the identification of the same heterozygous MDM4-variant ( NM_002393.5:c.1361C>T, p.(Thr454Met)) previously reported by Toufektchan et al.. Subsequent analyses of the parents showed maternal inheritance. Additional TL measurement showed no significant shortening of TL for all family members. Physical examination and medical history of the mother revealed no relevant abnormalities. Patient 2 is a male patient who, at the age of six years, first showed thrombocytopenia and leukopenia. During follow-up, he developed liver dysfunction with persisting elevated transaminases at the age of eleven years and portal hypertension and esophageal varicosis at the age of 13. During follow-up, the patient developed progressive cytopenia at the age of 16 and BM hypocellularity with reduced and partially dysplastic megakaryopoiesis and granulopoiesis. Flow-FISH analyses revealed a TL below the 1% percentile in lymphocytes. Genetic work-up using trio-based WES of the parents and the patient showed a de-novo stopgain variant in MDM4 (NM_002393.5:c.1333C>T, p.(Arg445*)). Patient 3 is an adult 53-year-old male patient presenting with BM failure. Initial diagnostic work-up including BM biopsy showed hypocellular BM. FISH analysis of the BM sample revealed a deletion of 7q and the diagnosis of hypocellular myelodysplastic syndrome was established. TL measurement showed TL below the 1% percentile in lymphocytes. Clinical examination showed no TBD typical stigmata or abnormalities. However, hepatic steatosis was reported. Additional WES revealed a rare missense variant in MDM4 (NM_002393.5:c.1334G>A, p.(Arg445Gln)). Conclusions: Here, we provide strong evidence from three unrelated patients that genomic germline variants in MDM4 cause a disorder of insufficient telomere maintenance resulting in a phenotype resembling features of TBD. Similar to TBD, the age at disease onset of our reported patients varied from early infant age to adulthood. So far, a single family with a proposed pathogenic MDM4 variant had been reported, which left a degree of uncertainty concerning the pathogenicity of MDM4 variants in general. In summary, our data confirm that there is an MDM4-associated TBD disorder with a broad phenotypic clinical spectrum.

Profiling the male germline genome to unravel its reproductive potential

To identify specific germline mutations related to sperm reproductive competence, in couples with unexplained infertility. In this retrospective study, couples were divided according to whether they had successful intracytoplasmic sperm injection outcomes (fertile) or not (infertile). Ancillary sperm function tests were performed on ejaculates, and whole exome sequencing was performed on spermatozoal DNA. Sperm aneuploidy and gene mutation profiles were compared between the 2 cohorts as well as according to the specific reasons for reproductive failure. Center for reproductive medicine at a major academic medical center. Thirty-one couples with negative infertility workups and normal semen parameters. Couples with mutations on fertilization- or embryo development-related genes were subsequently treated by assisted gamete treatment or microfluidics, respectively. Intracytoplasmic sperm injection cycle outcomes including fertilization, clinical pregnancy, and delivery rates. Sperm aneuploidy was lower in the fertile group (4.0% vs. 8.4%). Spermatozoa from both cohorts displayed mutations associated with sperm-egg fusion (ADAM3A) and acrosomal development (SPACA1), regardless of reproductive outcome. The infertile cohort was then categorized according to the reasons for reproductive failure: absent fertilization, poor early embryo development, implantation failure, or pregnancy loss. Spermatozoa from the fertilization failure subgroup (n = 4) had negligible PLCζ presence (10% ± 9%) and gene mutations (PLCZ1, PIWIL1, ADAM15) indicating a sperm-related oocyte-activating deficiency. These couples were successfully treated by assisted gamete treatment in their subsequent cycles. Spermatozoa from the poor early embryo development subgroup (n = 5) had abnormal centrosomes (45.9% ± 5%), and displayed mutations impacting centrosome integrity (HAUS1) and spindle/microtubular stabilization (KIF4A, XRN1). Microfluidic sperm processing subsequently yielded a term pregnancy. Spermatozoa from the implantation failure subgroup (n = 7) also had abnormal centrosomes (53.1% ± 13%) and carried mutations affecting embryonic implantation (IL9R) and microtubule and centrosomal integrity (MAP1S, SUPT5H, PLK4), whereas those from the pregnancy loss subgroup (n = 5) displayed mutations on genes involved in trophoblast development (NLRP7), cell cycle regulation (MARK4, TRIP13, DAB2IP, KIF1C), and recurrent miscarriage (TP53). By assessing the sperm genome, we identified specific germline mutations related to various reproductive processes. This information may clarify elusive factors underlying reproductive competence and enhance treatment for couples with unexplained infertility.

A case report of anti‐N‐methyl‐d‐aspartate receptor encephalitis with chromosomally integrated human herpesvirus 6

AbstractChromosomally integrated human herpesvirus 6 (ciHHV6) is a condition where HHV6‐DNA is integrated into the host germline genome. ciHHV6 can be misdiagnosed as active HHV6 infection. We report a 30‐year‐old woman presenting with psychological symptoms without a history of immunodeficiency. She had an ovarian teratoma and anti‐N‐methyl‐D‐aspartate receptor (NMDAR) antibodies in the cerebrospinal fluid (CSF) with HHV6‐DNA in the serum and CSF. The final diagnosis was anti‐NMDAR encephalitis and ciHHV6 because laparoscopic oophorectomy and immunotherapy ameliorated her symptoms and HHV6‐DNA was detected in her oral mucosa cells. This case suggests the need to assess whether HHV6‐DNA is related to infection or ciHHV6 when HHV6‐DNA is detected in the CSF of patients with encephalitis.

Identification and Characterization of PIWI-Interacting RNAs in Spinyhead Croakers (Collichthys lucidus) by Small RNA Sequencing

PIWI-interacting RNAs (piRNAs) are an emerging class of small RNAs which protect the animal germline genome against deleterious transposable elements. Nevertheless, the characteristics and sex-related expression patterns of piRNA in Collichthys lucidus remain unknown. In this study, we first performed systematic next-generation high-throughput sequencing in C. lucidus ovaries and testes. We identified 3,027,834 piRNAs across six gonad libraries. Of these, 2225 piRNAs were differently expressed between testes and ovaries; 1195 were upregulated and 1030 downregulated in the testes. Interestingly, the potential target genes of 208 differentially expressed piRNAs had sex-related functions, including germ cell development, gonad development, ovarian follicle development, gamete generation, spermatid development, and spermatogenesis. Moreover, these target genes are involved in the TGF-β, Wnt, MAPK, mTOR, VEGF, and PI3K-Akt pathways. Further, 10 piRNAs were derived from Nectin2 and Mea1, which play important roles in sexual reproduction, male gamete generation, and germ cell development. We also identified 5482 piRNA clusters across the gonads, among which 139 piRNA clusters were uniquely expressed in the testes and 98 in the ovaries. The expression of core sex-related piRNA was validated by real-time PCR. Overall, our findings provide significant insights into C. lucidus’ sex-related piRNAs.

BRCA1/2 Variants Identified Through Tumor Genomic Profiling: Assessing Genetic Counseling Outcomes.

As tumor genomic profiling (TGP) is increasingly used to help guide cancer treatment, BRCA variants, which may or may not be reflective of the germline genome, are being identified. As TGP use increases, it is becoming an important tool for referral to genetic counseling and identifying patients with hereditary cancer syndromes such as hereditary breast and ovarian cancer. This study explores genetic counseling referral patterns and germline implications of patients found to have pathogenic BRCA1/2 variants identified through TGP. Participants include patients at Huntsman Cancer Institute undergoing TGP through a single commercial laboratory between March 2014 and July 2018. A retrospective chart review was conducted for 62 patients found to have pathogenic variants (PVs) in BRCA1/2 on TGP. Data on genetic counseling referrals and uptake, germline test results, family history, and patient demographics were collected. In the study time frame, 1,899 patients underwent TGP. Testing identified 67 PVs in BRCA1 (23 variants) or BRCA2 (44 variants) in 62 patients. Thirty-five patients first received a referral to a genetic counselor following TGP with 33 patients completing genetic counseling. Of the 30 patients who pursued germline genetic testing following TGP, 11 were discovered to have a previously unknown germline BRCA PV. Nine of these patients were the first in their family diagnosed with hereditary breast and ovarian cancer. This study represents one institution's experience with genetic counseling referrals, uptake, and germline results following TGP. For some patients, TGP will be the first indicator of an underlying hereditary condition. Identifying patients with PVs (which may be germline) through TGP is an important new genetic counseling referral tool that can have important implications for the patient and their family.

Abstract IA030: A population-based, whole genome sequencing approach to mapping the genetic basis of mesenchymal malignancies

Abstract Cancer genetics has to date focused on epithelial malignancies, identifying multiple histotype-specific pathways underlying cancer susceptibility. Sarcomas are rare malignancies predominantly derived from embryonic mesoderm. To identify novel pathways specific to mesenchymal cancers, whole genome germline sequencing was performed on 1,644 sporadic cases, and 3,205 matched healthy elderly controls. Using an extreme phenotype design, a combined rare variant burden and ontologic analysis identified two new sarcoma-specific pathways involved in mitotic and telomere functions. Variants in centrosome genes are linked to malignant peripheral nerve sheath and gastrointestinal stromal tumors, while heritable defects in the shelterin complex link susceptibility to sarcoma, melanoma and thyroid cancers. These studies indicate a specific role for heritable defects in mitotic and telomere biology in risk of sarcomas. Citation Format: David M. Thomas. A population-based, whole genome sequencing approach to mapping the genetic basis of mesenchymal malignancies [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr IA030.

Emerging roles and functional mechanisms of PIWI-interacting RNAs.

PIWI-interacting RNAs (piRNAs) are a class of small non-coding RNAs that associate with proteins of the PIWI clade of the Argonaute family. First identified in animal germ line cells, piRNAs have essential roles in germ line development. The first function of PIWI-piRNA complexes to be described was the silencing of transposable elements, which is crucial for maintaining the integrity of the germ line genome. Later studies provided new insights into the functions of PIWI-piRNA complexes by demonstrating that they regulate protein-coding genes. Recent studies of piRNA biology, including in new model organisms such as golden hamsters, have deepened our understanding of both piRNA biogenesis and piRNA function. In this Review, we discuss the most recent advances in our understanding of piRNA biogenesis, the molecular mechanisms of piRNA function and the emerging roles of piRNAs in germ line development mainly in flies and mice, and in infertility, cancer and neurological diseases in humans.

Detection of relevant pharmacogenetic information through exome sequencing in oncology.

Background: Germline sequencing of individual genomes can detect alleles responsible for adverse drug reactions (ADRs) in relation to chemotherapy, targeted agents, antiemetics or pain treatment. Materials & methods: To evaluate the interest of such pharmacogenetic information, the authors retrospectively analyzed genes known to have an impact on cancer therapy in a cohort of 445solid cancers patients. Results: Six patients treated with 5-fluorouracil carrying one DPYD variant classified as 1A showed decreased drug mean clearance (p=0.01). Regarding CYP2D6, all patients (n=5) with predicted CYP2D6 poor or ultra-rapid metabolizer status experienced adverse drug reactions related to opioid therapy. Conclusion: Genomic germline sequencing performed for theragnostic issues in patients with a solid tumor, can provide relevant information about common pharmacogenetic alleles.

Co-option of the piRNA pathway to regulate neural crest specification.

Across Metazoa, Piwi proteins play a critical role in protecting the germline genome through piRNA-mediated repression of transposable elements. In vertebrates, activity of Piwi proteins and the piRNA pathway was thought to be gonad specific. Our results reveal the expression of Piwil1 in a vertebrate somatic cell type, the neural crest. Piwil1 is expressed at low levels throughout the chicken neural tube, peaking in neural crest cells just before the specification event that enables epithelial-to-mesenchymal transition (EMT) and migration into the periphery. Loss of Piwil1 impedes neural crest specification and emigration. Small RNA sequencing reveals somatic piRNAs with sequence signatures of an active ping-pong loop. RNA-seq and functional experiments identify the transposon-derived gene ERNI as Piwil1’s target in the neural crest. ERNI, in turn, suppresses Sox2 to precisely control the timing of neural crest specification and EMT. Our data provide mechanistic insight into a novel function of the piRNA pathway as a regulator of somatic development in a vertebrate species.

Z-DNA is remodelled by ZBTB43 in prospermatogonia to safeguard the germline genome and epigenome

Mutagenic purine–pyrimidine repeats can adopt the left-handed Z-DNA conformation. DNA breaks at potential Z-DNA sites can lead to somatic mutations in cancer or to germline mutations that are transmitted to the next generation. It is not known whether any mechanism exists in the germ line to control Z-DNA structure and DNA breaks at purine–pyrimidine repeats. Here we provide genetic, epigenomic and biochemical evidence for the existence of a biological process that erases Z-DNA specifically in germ cells of the mouse male foetus. We show that a previously uncharacterized zinc finger protein, ZBTB43, binds to and removes Z-DNA, preventing the formation of DNA double-strand breaks. By removing Z-DNA, ZBTB43 also promotes de novo DNA methylation at CG-containing purine–pyrimidine repeats in prospermatogonia. Therefore, the genomic and epigenomic integrity of the species is safeguarded by remodelling DNA structure in the mammalian germ line during a critical window of germline epigenome reprogramming.

GTSF1 accelerates target RNA cleavage by PIWI-clade Argonaute proteins

Argonaute proteins use nucleic acid guides to find and bind specific DNA or RNA target sequences. Argonaute proteins have diverse biological functions and many retain their ancestral endoribonuclease activity, cleaving the phosphodiester bond between target nucleotides t10 and t11. In animals, the PIWI proteins—a specialized class of Argonaute proteins—use 21–35 nucleotide PIWI-interacting RNAs (piRNAs) to direct transposon silencing, protect the germline genome, and regulate gene expression during gametogenesis1. The piRNA pathway is required for fertility in one or both sexes of nearly all animals. Both piRNA production and function require RNA cleavage catalysed by PIWI proteins. Spermatogenesis in mice and other placental mammals requires three distinct, developmentally regulated PIWI proteins: MIWI (PIWIL1), MILI (PIWIL2) and MIWI22–4 (PIWIL4). The piRNA-guided endoribonuclease activities of MIWI and MILI are essential for the production of functional sperm5,6. piRNA-directed silencing in mice and insects also requires GTSF1, a PIWI-associated protein of unknown function7–12. Here we report that GTSF1 potentiates the weak, intrinsic, piRNA-directed RNA cleavage activities of PIWI proteins, transforming them into efficient endoribonucleases. GTSF1 is thus an example of an auxiliary protein that potentiates the catalytic activity of an Argonaute protein.

Neurofibromatosis-1 Gene Mutational Profiles Differ Between Syndromic Disease and Sporadic Cancers.

Variants in the neurofibromatosis type 1 (NF1) gene are not only responsible for the NF1 cancer predisposition syndrome, but also frequently identified in cancers arising in the general population. While germline variants are pathogenic, it is not known whether those that arise in cancer (somatic variants) are passenger or driver variants. To address this question, we sought to define the landscape of NF1 variants in sporadic cancers. NF1 variants in sporadic cancers were compiled using data curated on the c-Bio database and compared with published germline variants and Genome Aggregation Database data. Pathogenicity was determined using Polyphen and Sorting Intolerant From Tolerant prediction tools. The spectrum of NF1 variants in sporadic tumors differ from those most commonly seen in individuals with NF1. In addition, the type and location of the variants in sporadic cancer differ from germline variants, where a high proportion of missense variants were found. Finally, many of the sporadic cancer NF1 variants were not predicted to be pathogenic. Taken together, these findings suggest that a significant proportion of NF1 variants in sporadic cancer may be passenger variants or hypomorphic alleles. Further mechanistic studies are warranted to define their unique roles in nonsyndromic cancer pathobiology.

Dynamics of reproductive genetic technologies: Perspectives of professional stakeholders.

Reproductive and genetic medicine are evolving rapidly, and new technologies are already impacting current practices. This includes technologies that can identify a couples’ risk of having a child with a genetic disorder. Responsible implementation of new technologies requires evaluation of safety and ethics. Valuable insights for shaping governance processes are provided by various stakeholders involved, including healthcare professionals. Their willingness to adopt these technologies and guide the necessary systemic changes is required for the successful implementation of these technologies. In this study, twenty-one semi-structured interviews were conducted with professionals from different disciplines in the field of reproductive and genetic healthcare in the Netherlands. Three emerging technologies were discussed: expanded carrier screening (ECS), non-invasive prenatal diagnosis (NIPD) and germline genome editing (GGE). By probing stakeholders’ views, we explored how culture, structure and practice in healthcare is being shaped by innovations and changing dynamics in genetic and reproductive medicine. The general consensus was that the implementation of reproductive genetic technologies nationwide is a slow process in Dutch healthcare. A “typical Dutch approach” emerged that is characterized by restrictive legislation, broad support for people living with disabilities, values of an egalitarian society and limited commercialisation. Different scenarios for embedding ECS in future practice were envisioned, while implementation of NIPD in clinical practice was considered obvious. Views on GGE varied among stakeholders. Previous implementation examples in the Netherlands suggest introduction of new technology involves an organized collective learning process, with pilot studies and stepwise implementation. In addition, introducing and scaling up new technologies is complex due to perceived barriers from the legislative framework and the complex relationship between the government and stakeholders in this area. This paper describes how the international trends and advances of technologies are expected to manifest itself in a national setting.