Cornelia de Lange syndrome (CdLS) is a rare congenital disorder characterised by craniofacial features, growth retardation, limb anomalies, and intellectual disability. The condition arises from pathogenic variants in genes encoding cohesin complex components or regulators, most frequently NIPBL. Despite advances in genomic testing, approximately 30% of clinically diagnosed cases remain unresolved, suggesting the presence of non-coding variants. We investigated 10 classical CdLS patients negative for pathogenic variants in NIPBL, SMC1A, SMC3, RAD21, and HDAC8. Genome-wide methylation profiling was performed to identify CdLS-specific epigenetic signatures. Episignature-positive cases underwent trio-based deep sequencing of the entire NIPBL locus while targeted NIPBL RNA sequencing was used to assess splicing. Whole-genome sequencing (WGS) was performed in episignature-negative individuals. Five of ten patients exhibited a positive CdLS episignature in blood, saliva, or skin. Deep sequencing identified de novo deep intronic NIPBL variants in all cases, and two additional variants in episignature-negative patients. Seven distinct intronic variants were identified across introns 4, 10, 21, and 32. In silico tools predicted the creation or activation of cryptic splice sites in six variants. RNA sequencing confirmed pseudoexon inclusion in three patients, leading to premature termination codons and predicted nonsense-mediated decay. Tissue-specific variation in aberrant transcript expression was observed between blood and fibroblasts. We conclude that deep intronic NIPBL variants represent an under-recognised cause of CdLS, frequently escaping detection by conventional exome analysis. Integration of methylation episignatures, deep intronic sequencing, and RNA analysis enhances diagnostic yield and provides insight into the regulatory architecture of cohesinopathies.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare cancer predisposition syndrome in which uterine leiomyomas (ULs) are common, morbid, and often precede renal cancer diagnosis. We synthetized evidence on the clinical presentation, pathology, management, and reproductive outcomes of HLRCC-associated ULs. MEDLINE, Embase, Scopus, Web of Science Core Collection, and ClinicalTrials.gov were searched for peer-reviewed studies reporting original data on ULs in HLRCC. Two reviewers independently screened articles and extracted data. Individual patient data from 410 patients and aggregate data from 27 observational studies were included. Mean age at UL diagnosis was 32.4 years. Most patients (89.1%) had multiple fibroids, were symptomatic (88.1%), and commonly reported abnormal uterine bleeding (80.6%) or pelvic pain (41.2%). Average maximum fibroid size was 7.5 cm. Fumarate hydratase (FH) and/or S-(2-succino)cysteine (2SC) immunohistochemistry studies showed abnormal staining in >85% of tumors. Surgical intervention was required in 94.4% of patients; hysterectomy was most common (67.0%), at a mean age of 35.2 years, whereas myomectomy was performed in 27% at 27.7 years. Despite a family history of HLRCC-related features in 88.8% of patients, only 0.6% underwent germline FH testing before gynecologic diagnosis. Fertility and obstetric outcomes were sparsely reported. Uterine leiomyosarcoma was rare, with an uncertain syndromic association. HLRCC-associated ULs are genetically, morphologically, and clinically distinct from sporadic fibroids, yet remain under-recognized. Integrating age, multiplicity, symptoms, family history, and pathology-triggered FH/2SC immunohistochemistry into gynecologic practice would enable earlier germline testing, renal surveillance, and reproductive counseling. Prospective registries are needed to define genotype-phenotype relationships, fertility outcomes, and leiomyosarcoma risk.

Sharing clinical and genomic data is essential for accurate variant interpretation, the advancement of genomic research, and supporting couples planning to conceive. This cross-sectional study examined attitudes toward newborn genomic data sharing in a cohort of peripartum mothers in Slovenia. Among the 1111 respondents, 84% expressed willingness to share anonymized genomic data to benefit other couples and to advance novel diagnostic and preventive strategies. Support was reported by 87% for clinical applications and by 59% for research purposes, while 74% favored international data sharing. Conversely, pronounced hesitation emerged regarding disclosure of identifiable data for non-medical uses, particularly involving insurance providers (82%). Willingness to share genomic data was positively associated with higher educational attainment (p < 0.001), higher levels of genetic knowledge (p < 0.001), and prior experience with genetic testing (p = 0.013). These results emphasize the role of public understanding and trust in the ethical integration of genomic newborn screening initiatives.

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder affecting ~1:7500 individuals characterised by recurrent chronic respiratory infections, bronchiectasis, laterality defects, and infertility. While at least 60 PCD-causing genes are reported, approximately 30% of patients remain without a confirmed molecular diagnosis. PCD caused by biallelic HYDIN variants is difficult to diagnose due to a 98% homologous pseudogene (HYDIN2). Additionally, functional ciliary diagnostic testing can be inconclusive due to the lack of discernible HYDIN ciliary ultrastructure defects by electron microscopy. Our aim was to diagnose genetically unresolved PCD patients with strong clinical suspicion of HYDIN defects using RNA sequencing (RNA-seq). RNA-seq was performed on total RNA extracted from patients' nasal epithelium cultured for 21 days at the air-liquid interface. Splicing abnormalities were detected using rMATS and genome-aligned reads were manually inspected using Integrative Genome Viewer. Thirteen individuals had strong clinical suspicion of PCD, normal TEM and inconclusive genetics: 11/13 had a single pathogenic or likely pathogenic variant in HYDIN, 1/13 had no variants, and 1/13 required clarification of variant origin (HYDIN vs HYDIN2). RNA-seq resolved 11/13 (85%) of cases. The same complex pathogenic aberrant splicing events were seen in seven unrelated patients. This abnormal splice pattern was caused by a large 10-kilobase deletion spanning intron 17 to intron 18. RNA-seq increases the diagnostic yield for patients with suspected PCD and has exposed a HYDIN 'hotspot' variant, increasing the observed prevalence of HYDIN-related cases within our genetically diagnosed cohort. Routine PCD genomics testing will now incorporate investigation of this genetic region of HYDIN.

Mitochondrial diseases (MD) are the most common inherited metabolic disorders and show marked clinical and genetic heterogeneity. Despite widespread use of whole-exome (WES) and whole-genome sequencing (WGS), nearly half of patients remain without molecular diagnosis, partly due to difficulties in interpreting variants affecting RNA splicing or gene expression. RNA sequencing (RNA-seq) has shown promise in research settings, few studies have evaluated its feasibility in routine clinical diagnostics under technical and financial constraints. We evaluated the implementation of RNA-seq in a routine diagnostic workflow for MD using fibroblasts from 38 patients, including 8 analyzed with a candidate-gene approach and 30 with an untargeted strategy. To optimize the workflow and improve sensitivity in untargeted analyses, we focused on aberrant expression detection using OUTRIDER with complementary analytical strategies, including multiple testing correction restricted to disease-relevant gene sets and Z-score-based outlier detection combined with phenotype-driven prioritization using Human Phenotype Ontology terms. This combined strategy enabled diagnostic performance comparable to previously published studies while optimizing resources. Pathogenicity was confirmed in 75% of targeted cases (6/8). In the untargeted cohort, new molecular diagnoses were established in 13% of patients (4/30), despite fewer samples than typically recommended and minimizing costs. Our study demonstrates that RNA-seq is feasible and clinically informative in a routine diagnostic setting despite analytical and financial constraints. RNA-seq represents a valuable complement to WES/WGS for improving variant interpretation and diagnostic yield in MD. We propose a practical framework for its implementation alongside genome sequencing in routine diagnostics.

In certain populations, founder pathogenic variants are a common cause of Lynch syndrome. Here, we report the identification of a novel Portuguese founder variant, NM_000179.3 (MSH6):c.2061 T > G (p.Cys687Trp). Our study examined 14 probands and 19 additional family members who carry this variant. With one exception, haplotype data are consistent with a single origin for all heterozygotes, likely in the Leiria District of Portugal. We investigated the clinicopathological consequences of this variant and found that, as previously reported for MSH6 pathogenic variants, (a) the presence of a pathogenic variant is not reliably associated with loss of MSH6 expression or microsatellite instability and (b) endometrial cancer is the most common associated phenotype. Due to the requirement to apply the BP5 code according to ACMG criteria, the variant is classified as a variant of uncertain significance rather than likely pathogenic. Nevertheless, the balance of evidence we present here suggests that this variant is associated with an increased risk for MSH6-related Lynch syndrome tumors.

Amyotrophic lateral sclerosis (ALS) is a common neurodegenerative disease. Its aetiology is complex, but a subset is caused by single-gene pathogenic variants (monogenic ALS). The most common ALS-associated genes are SOD1 and C9orf72. We evaluated the implementation of genetic testing and associated genetic counselling for ALS at a Finnish tertiary-level university hospital. We used the electronic patient records of Oulu University Hospital (Oulu, Finland) to identify patients diagnosed with ALS between 2000 and 2023. Medical records were reviewed for neurological diagnosis and completion of genetic testing and counselling. We identified a total of 387 patients diagnosed with ALS. Of these, 225 patients (58%) were offered genetic testing, and 186 (83%) accepted. The offer for genetic counselling was given to 60 patients, of whom 46 (77%) attended counselling, whilst 13 did not. The proportion of patients who declined counselling did not differ between those with SOD1 and C9orf72 variants. Among the 143 patients tested for SOD1 variants, 36 (25%) were confirmed to harbor the ALS-associated p.Asp91Ala variant in SOD1; 31 were homozygous and 5 were heterozygous. In the 96 analyses of the C9orf72 hexanucleotide expansion, the diagnostic yield was 27 (28%) patients. A positive family history was more common in SOD1-ALS than in C9orf72-ALS (53% vs 33%). Nearly one fifth of patients declined testing and over one fifth of those with genetic ALS did not attend genetic counselling. The reasons for this warrant further investigation.

Parental perspectives are central in ongoing debates about genomic newborn screening (gNBS). This study examined (expecting) parents' interest in gNBS in Germany. We hypothesized that condition characteristics (actionability, genetic penetrance) and personal factors (e.g., attitudes towards gNBS, anticipated coping, risk perception) predict parental interest in gNBS for their child. We also investigated determinants of risk perception. In an online survey (N = 556; 60% women; M age=35 years), participants evaluated nine hypothetical case-scenarios that systematically varied penetrance and actionability. Data were analyzed using multilevel models, latent profile analysis and descriptive statistics. Overall, (expecting) parents showed a strong demand for information, driven more by perceived benefits than concerns. Two profiles emerged: one highly open and one seeking information more selectively. Across scenarios, higher interest in potential gNBS findings was associated with high actionability and moderate penetrance (50-74%) of possible target conditions, prior experience with chronic conditions, greater anticipated coping with test results, higher perceived probability of condition development, and more positive than negative attitudes toward gNBS. Perceived probability (subjective risk) predicted interest better than objective risk (penetrance), but was itself well explained by penetrance. Diagnostic concern (worry about disease manifestation) was consistently higher than perceived probability across penetrance levels and more pronounced in women. Implications include avoiding the reporting of low-penetrance findings due to disproportionate diagnostic concern and providing decision aids to support informed parental decision-making.

Precision medicine aims to revolutionise healthcare by providing personalised treatments based on individual genetic variations. A systematic review was conducted to explore ethnic inequalities in precision medicine, focusing on representation of ethnic minorities or indigenous minority groups in the reporting of genomic research in any healthcare setting in the UK or other high-income countries with similar healthcare systems. Seven electronic databases (MEDLINE, EMBASE, PsycINFO, CINAHL, ProQuest Central, ASSIA and Scopus) were searched from inception to October 2022. Two authors independently screened papers, extracted data, and assessed quality. This review included 137 studies and a narrative synthesis was performed. The review included both genome-wide association studies (GWAS) and related studies of polygenic risk scores, and consistently identified that these studies failed to report or inadequately reported genomic results in certain ethnic minorities or indigenous minority groups. Downstream this compromises the value of this research to improve genomic services for multi-ethnic populations in High-income countries. This can be improved by purposefully recruiting participants from these underrepresented communities.Review registration: Registered with the International Prospective Register of Systematic Reviews (PROSPERO) in November 2022; ID: CRD42022371245.

Genetic variant interpretation in hypertrophic cardiomyopathy (HCM) evolves as population reference datasets expand, gene-disease validity assessments examine new candidate genes and additional functional and segregation evidence accumulates. Periodic re-interpretation is, therefore, necessary. Likely pathogenic/pathogenic (LP/P) variants and variants of unknown significance (VUS) were re-evaluated in 2154 HCM index cases using the ACMG/AMP framework. Gene selection was based on ClinGen gene-disease validity assessments. Overall, 12.8% of 1355 variants in HCM genes were reclassified, with 7.5% resulting in clinically meaningful impact (3.5% upgrading from VUS to LP/P and 4% downgrading from LP/P to VUS). Variant reclassification affected the genetic status of 86 individuals (4.0%), including loss of LP/P status in 47 (2.2%) and new gene-positive diagnoses in 39 (1.8%). Of 536 unique variants, 19 (3.5%) were upgraded from VUS to LP/P, 44 (8.2%) were downgraded from LP/P to VUS and 287 (53.5%) maintained LP/P status. Variants in MYBPC3 and MYH7 largely retained pathogenic classification (92.0% and 83.2% unchanged). TNNT2 showed the highest proportion of VUS upgrades (28.6%) alongside high retention of pathogenic variants. The largest LP/P to VUS shifts were noted in ACTC1 (50.0%), MYL3 (42.9%), TPM1 (42.9%) and TNNI3 (20.0%). In this large HCM cohort, variant re-evaluation resulted in a modest but clinically relevant reclassification of genetic variants. MYBPC3 and MYH7 classifications were largely unaltered, showing limited net change. Upgrades in TNNT2 variants, the third most frequent gene in this cohort, are consistent with consolidation of locus-specific evidence and are important given their association with adverse outcomes, despite modest hypertrophy.

As part of the third French National Plan for Rare Diseases, the AnDDI-Rares network initiated a nationwide study in 2019 to assess how diagnostic practices for developmental anomalies have evolved over the last decade (2012-2022), in the context of the implementation of genome sequencing (GS) capabilities via the France Genomic Medicine Plan. We analyzed diagnostic rates in 34 French centers for developmental diseases, comparing a randomly selected week in 2012 with one in 2022. Secondary outcomes were diagnostic delays and GS efficiency. A total of 430 patients were identified in 2012 and 551 in 2022, a 28% increase in activity. The overall diagnostic yield rose from 16% in 2012 to 27% in 2022 (p < 0.001), in parallel with the increased use of next-generation sequencing (NGS) approaches, and the shift from targeted gene panels toward GS. Among previously undiagnosed patients from the 2012 cohort who pursued further investigations, NGS enabled additional diagnoses with GS showing a high diagnostic yield (42%) in individuals with longstanding diagnostic odysseys. Significant heterogeneity in strategies persisted, highlighting the impact of, and unequal access to GS across centers. These results highlight advancements in diagnostic practices and the pivotal role of Next-Generation Sequencing. Nonetheless, unequal access, attrition, and limited uptake of renewed investigations reveal persistent barriers. Continuous patient engagement and coordinated efforts are required to promote GS-first approaches and ensure equitable access across the healthcare system.

Therapeutic advances and the rapid, cost-effective development of next-generation sequencing (NGS) have increased interest in expanding newborn screening (NBS) through genomics. The SeDeN-p2 study assessed the acceptability among healthcare professionals in France, of expanding NBS, particularly with genetics as a first-line test, by examining areas of convergence and divergence in their expectations. A national cross-sectional survey was conducted between June and December 2021 via professional networks and learned societies involved in NBS and genetics, in partnership with the French Society of Newborn Screening. The questionnaire comprised 101 closed-ended and 14 open-ended questions. After data cleaning, 1077 responses were analysed. Respondents were mainly paediatricians (43%), gynaecologists or midwives (36%), and medical geneticists or genetic counsellors (17%). Support for the inclusion of treatable childhood-onset conditions was very high, with over 95% endorsing their integration into NBS, although 29% still considered the current NBS programme sufficient. Views varied substantially by specialty, particularly regarding the scope of conditions and the use of NGS. Genetics professionals were more conservative, especially concerning variants with limited actionability, organisational constraints, and interpretive uncertainty, while midwives and gynaecologists were generally more favourable. Convergence was strongest for treatable paediatric conditions and shared ethical concerns, notably data misuse, psychosocial burden, and the child's future autonomy. The need for improved communication with families was widely emphasised. The SeDeN-p2 study shows strong but conditional support among French healthcare professionals for integrating genetics into NBS, providing key insights to inform future policy and practice.

Delays in accessing clinical genetics services are increasing globally. This systematic review and Synthesis Without Meta-analysis investigated the types and frequency of harms during delayed access to clinical genetics services (PROSPERO CRD42024601622). We searched peer-reviewed literature across multiple databases and included Australian policies, white papers and government documents reporting patient harms. Certainty of evidence was assessed using GRADE. Five studies met inclusion criteria. The clearest signal was non-attendance, which rose with longer waits across two studies (n = 1280). Martinez et al. observed mortality among clinical genetics waiting-list patients. Oncology and other tertiary specialties with higher mortality risk are commonly referred to clinical genetics. A randomised trial (n = 590) of cancer genetics patients found psychological distress during waiting, with high baseline distress persisting despite intervention. A large cohort (n = 48,622) reported family-level harms, including deaths among at-risk relatives. Certainty was moderate for non-attendance and very low for mortality, distress and family harms due to limited studies and imprecision. Direct causal evidence and significant associations linking waiting time delays to harm remain sparse; this represents a significant gap in the evidence base. Better evidence on presentations and factors linked to harm would support more effective waiting-list management. This review characterises the types of harm experienced by patients during the clinical genetics waiting period, providing a foundation for future investigation and demonstrating opportunity for improved services. System-level action is needed, including safety evaluation of emerging models of care, structured prioritisation, improved genetics literacy and transparent waiting-list management to strengthen equity and safety.

Large-scale genomic medicine implementation efforts are presenting relevant and authentic opportunities for the health workforce to learn genomics in the workplace, particularly from genomic expert colleagues or 'champions'. This paper presents novel insights on genomic experts' role and influence on learning genomics from the perspective of physicians not trained in genetics. As part of a study on workplace learning of genomics, longitudinal qualitative datasets were collected in 2021-2023 from ten non-genetics physicians working in hospitals in Victoria, Australia. Reflexive thematic analysis was used to characterise participants' perceptions of, and workplace interactions with, genomic experts. Deductive content analysis was then applied to sort and synthesise participants' relationships with genomics experts. Designated the 'Genomics Friend', these individuals are trained in genetics or recognised as same-specialty genomic champions and perceived as trusted and accessible sources of genomic expertise. Participants who had a Genomics Friend leveraged their established relationship on an ad hoc basis to address identified knowledge gaps. Sorting participants into the Genomics Friend Relationship Matrix demonstrated how having a Genomics Friend enhanced genomic workplace learning and practice for physicians across different career stages and specialties. These findings offer insights into how intra- and inter-disciplinary interactions and collegial relationships provide professional development opportunities through workplace learning. Moreover, we consider how genomic expert 'friends' could support implementation efforts by facilitating the health workforce to learn, adopt and practise genomics.