Exploring the Efficacy of Pembrolizumab in Combination with Carboplatin and Weekly Paclitaxel for Frail Patients with Advanced Non-Small-Cell Lung Cancer: A Key Investigative Study.

INTRODUCTION: Immune checkpoint blockers have revolutionized the first-line treatment of advanced non-small-cell lung cancer (NSCLC). Pembrolizumab, an anti-PD-1 monoclonal antibody, is a standard therapy either alone or in combination with chemotherapy (chemo-IO). The current study explores the efficacy and safety of pembrolizumab with carboplatin and weekly paclitaxel in a cohort of frail patients. METHODS: A monocentric retrospective study was conducted between 22 September 2020 and 19 January 2023 regarding patients with stage IV NSCLC treated with chemo-IO combination: carboplatin (AUC 5 mg/mL/min; Q4W), weekly paclitaxel (90 mg/m2 on days 1, 8, and 15), and pembrolizumab (200 mg Q4W). The primary objective was real-world progression-free survival (rwPFS). Secondary objectives were overall survival (OS), toxicity profile, and outcomes based on histological subtype. RESULTS: A total of 34 patients (20 squamous and 14 non-squamous NSCLC) benefited from the chemo-IO regimen for frail patients; 41.9% had an ECOG-PS = 2. The median age was 75.5 years. We observed an overall response rate (ORR) of 55.9%. Notably, squamous NSCLC exhibited a significantly higher ORR (80%) than non-squamous NSCLC (21.4%); p = 0.001. The median rw-PFS was 10.6 months (95% CI [6.0, NA]), with 6- and 12-month rw-PFS rates of 69% and 45.8%, respectively. The median OS was not reached, with 12- and 18-month OS rates of 75.6% and 61.4%, respectively. The median number of maintenance cycles of pembrolizumab was 5 (0; 27). Nine patients (26.5%) experienced a toxicity related to chemotherapy leading to a reduction of the dose administered and, in five patients (14.7%), to the permanent discontinuation of chemotherapy. Six patients (17.6%) had an immune-related adverse event leading to the discontinuation of immunotherapy. DISCUSSION: Pembrolizumab plus carboplatin and weekly paclitaxel demonstrates promising efficacy and safety in frail patients with metastatic NSCLC, especially for ORR in sq-NSCLC. Prospective studies focusing on frail populations are warranted in order to validate these findings and optimize therapeutic strategies in the first-line setting.

Allelic heterogeneity in a patient with postzygotic MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities.

A case of mosaic MTOR-associated hemimegalencephaly and hypomelanosis of Ito, died at 33 probably because of sudden unexpected death in epilepsy. Assessment of the variant allele fraction (VAF) in different tissues postmortem showed high variability not correlated with clinical features, representing the most detailed assessment of VAFs in different tissues to date.

Prognostic impact of the number and total tumor burden of secondary cerebral lesions in patients with resected brain metastases of non-small cell lung cancers.

OBJECTIVE: Systemic therapeutic advancements have improved the prognosis of cancer patients, leading to surgery more frequently being carried out for patients with multiple brain metastases (BM). The underlying evidence for the strategy is currently lacking. This study aimed to evaluate the prognostic significance of the number of BM and total tumor burden (TTB) on the overall survival (OS) of patients with resected BM of non-small cell lung cancer (NSCLC) in a modern series. METHODS: In this monocentric retrospective series, patients who underwent resection of BM of NSCLC between 2015 and 2021 were included. Demographic, clinical, and histological parameters were collected, and formal radiological volumetric analyses were performed. Prognostic biomarkers for cerebral progression-free survival (C-PFS) and OS were analyzed with univariate and multivariate Cox proportional hazards analysis. RESULTS: One hundred eighty-four patients were included in the study. Among these, 108 patients (58.7%) presented with a single brain metastasis, 36 patients (19.6%) with 2 BM, 22 patients (11.9%) with 3 BM, and 18 patients (9.8%) with more than 3 BM (maximum 15 BM). The mean ± SD (range) preoperative tumor burden was 23.1 ± 25.3 (1.1-145.3) cm3. The mean residual tumor burden after surgery was 0.3 ± 0.8 (0.0-6.3) cm3. By the time of the analysis, 128 patients (69.6%) had died. The median follow-up duration was 49.0 months (95% CI 39.6-63.6). The median OS was 19.2 months (95% CI 13.2-24.0), and the survival rates at 6 months, 1 year, and 2 years were 76% (95% CI 69%-82%), 61% (95% CI 53%-67%), and 43% (95% CI 35%-50%), respectively. The median C-PFS was 8.4 months (95% CI 7.2-12.0). In the Cox multivariate regression model, younger age (< 65 years), single brain metastasis, adjuvant brain radiation therapy, adjuvant use of targeted therapy, and TTB < 7 cm3 were all independent predictors of longer OS. CONCLUSIONS: In this era of modern systemic treatments for cancer, the number of BM and total cerebral tumor burden remain significant prognostic factors of OS. However, resection should be considered as an option even in those patients with multiple BM in order to enhance patient clinical status, enable further local and systemic treatment delivery, and improve their survival and quality of life.

Circulating tumour cells and PD-L1-positive small extracellular vesicles: the liquid biopsy combination for prognostic information in patients with metastatic non-small cell lung cancer.

BACKGROUND: Circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), and extracellular vesicles (EVs) are minimally invasive liquid biopsy biomarkers. This study investigated whether they predict prognosis, alone or in combination, in heterogenous unbiased non-small cell lung cancer (NSCLC) patients. METHODS: Plasma samples of 54 advanced NSCLC patients from a prospective clinical trial. CtDNA mutations were identified using the UltraSEEK™ Lung Panel (MassARRAY® technology). PD-L1 expression was assessed in small EVs (sEVs) using an enzyme-linked immunosorbent assay. RESULTS: At least one ctDNA mutation was detected in 37% of patients. Mutations were not correlated with overall survival (OS) (HR = 1.1, 95% CI = 0.55; 1.83, P = 0.980) and progression-free survival (PFS) (HR = 1.00, 95% CI = 0.57-1.76, P = 0.991). High PD-L1+ sEV concentration was correlated with OS (HR = 1.14, 95% CI = 1.03-1.26, P = 0.016), but not with PFS (HR = 1.08, 95% CI = 0.99-1.18, P = 0.095). The interaction analysis suggested that PD-L1+ sEV correlation with PFS changed in function of CTC presence/absence (P interaction = 0.036). The combination analysis highlighted worse prognosis for patients with CTCs and high PD-L1+ sEV concentration (HR = 7.65, 95% CI = 3.11-18.83, P < 0.001). The mutational statuses of ctDNA and tumour tissue were significantly correlated (P = 0.0001). CONCLUSION: CTCs and high PD-L1+ sEV concentration correlated with PFS and OS, but not ctDNA mutations. Their combined analysis may help to identify patients with worse OS. TRIAL REGISTRATION: NCT02866149, Registered 01 June 2015, https://clinicaltrials.gov/ct2/show/study/NCT02866149 .

Patient satisfaction, experience and preferences in the implementation of genetics teleconsultations in the North-eastern region of France.

INTRODUCTION: In France, few centres per region offer genetics consultations. Consequently, each centre covers a large area, often requiring patients to take a day off to travel long distances. In certain situations, genetic counselling in particular, a physical exam is not required. In these cases, teleconsultations between medical professional and patients, at the patient's location of choice, are an interesting offer. The COVID-19 pandemic has accelerated the implementation and the use of this type of consultation. With the aim of developing teleconsultation for certain types of referrals, a study of patient satisfaction, experience and preferences has been set up in our region. METHODS: 2307 patients who had a teleconsultation by phone or videoconferencing with professionals from one of five genetic centres in North-eastern France between March and December 2020 were asked by e-mail or by post to answer an online survey. RESULTS: 20% of the patients (n = 465) responded to the survey (80% women, 55% over 40 years old). In 64% of the cases (n = 299), the teleconsultation replaced a physical consultation due to the pandemic. In 56% of cases (n = 217), the consultations were conducted by videoconference. The teleconsultation involved the disclosure of results in 56% of cases (n = 260), a first consultation in 30% of cases (n = 138), and a follow-up consultation in 14% of cases (n = 67). The satisfaction rate was 96% (n = 447), with a rating of "excellent" in 72% of responses (n = 290) and "good" in 24% of responses (n = 157). Only 22% of the patients (n = 103), particularly patients who lived near the hospital or who were older than 70 years, would have preferred a physical consultation. Half of respondents (n = 232) declared that they avoided more than 1.5 h of transport, and 69% (n = 321) avoided taking a work day off. Patients were less often accompanied by a relative than if the consultation had taken place face-to-face (43%; n = 201 vs. 61%; n = 285). There was no change in responses during or after lock-down. CONCLUSION: This collection of feedback and analysis of patients' preferences has validated the long-term implementation of medical genetics teleconsultations in certain circumstances and indications, for patients who prefer this approach.

Optimal First-Line Medico-Surgical Strategy in Ovarian Cancers: Are We There Yet?

In spite of tremendous advances in advanced ovarian cancer management through the past decade, notably owing to surgical expertise and novel combination molecules (including bevacizumab and PARP inhibitors), the optimal initial sequential strategy remains a major concern. Indeed, following seminal clinical trials, primary cytoreductive surgery (PCS) followed by adjuvant systemic therapy and interval cytoreductive surgery (ICS) following neoadjuvant chemotherapy (NACT) have been positioned as validated alternatives with distinct pros and cons, although a definite response is still unassessed. In clinical practice, decisions between PCS and ICS rely on multilayer parameters: the tumor itself, the patient, and the health structure. In this state-of-the-art review, we will discuss the current evidence based on clinical trials and real-world data and highlight the remaining questions, including the fittest positioning of PCS vs. ICS and the optimal number of NACT cycles; subsequently, we will discuss current axes of research such as dedicated clinical trials and more global perspectives. These ongoing strategies and perspectives could contribute to improving the patient journey through personalized medicine.

Extreme phenotypic heterogeneity in non-expansion spinocerebellar ataxias.

Although the best-known spinocerebellar ataxias (SCAs) are triplet repeat diseases, many SCAs are not caused by repeat expansions. The rarity of individual non-expansion SCAs, however, has made it difficult to discern genotype-phenotype correlations. We therefore screened individuals who had been found to bear variants in a non-expansion SCA-associated gene through genetic testing, and after we eliminated genetic groups that had fewer than 30 subjects, there were 756 subjects bearing single-nucleotide variants or deletions in one of seven genes: CACNA1A (239 subjects), PRKCG (175), AFG3L2 (101), ITPR1 (91), STUB1 (77), SPTBN2 (39), or KCNC3 (34). We compared age at onset, disease features, and progression by gene and variant. There were no features that reliably distinguished one of these SCAs from another, and several genes-CACNA1A, ITPR1, SPTBN2, and KCNC3-were associated with both adult-onset and infantile-onset forms of disease, which also differed in presentation. Nevertheless, progression was overall very slow, and STUB1-associated disease was the fastest. Several variants in CACNA1A showed particularly wide ranges in age at onset: one variant produced anything from infantile developmental delay to ataxia onset at 64 years of age within the same family. For CACNA1A, ITPR1, and SPTBN2, the type of variant and charge change on the protein greatly affected the phenotype, defying pathogenicity prediction algorithms. Even with next-generation sequencing, accurate diagnosis requires dialogue between the clinician and the geneticist.

Comedications with Immune Checkpoint Inhibitors: Involvement of the Microbiota, Impact on Efficacy and Practical Implications.

Immune checkpoint inhibitors (ICIs) have been a major breakthrough in solid oncology over the past decade. The immune system and the gut microbiota are involved in their complex mechanisms of action. However, drug interactions have been suspected of disrupting the fine equilibrium necessary for optimal ICI efficacy. Thus, clinicians are facing a great deal of sometimes contradictory information on comedications with ICIs and must at times oppose conflicting objectives between oncological response and comorbidities or complications. We compiled in this review published data on the role of the microbiota in ICI efficacy and the impact of comedications. We found mostly concordant results on detrimental action of concurrent corticosteroids, antibiotics, and proton pump inhibitors. The timeframe seems to be an important variable each time to preserve an initial immune priming at ICIs initiation. Other molecules have been associated with improved or impaired ICIs outcomes in pre-clinical models with discordant conclusions in retrospective clinical studies. We gathered the results of the main studies concerning metformin, aspirin, and non-steroidal anti-inflammatory drugs, beta blockers, renin-angiotensin-aldosterone system inhibitors, opioids, and statins. In conclusion, one should always assess the necessity of concomitant treatment according to evidence-based recommendations and discuss the possibility of postponing ICI initiation or switching strategies to preserve the critical window.

[Combination strategies for checkpoint inhibition: Current practices and perspectives]. / Combinaisons d'inhibiteurs de points de contrôle immunitaires en oncologie : état de l'art et perspectives.

T-cell checkpoint blockade therapies have revolutionized treatment protocols and prognosis in patients with cancer. Pointed out by the success of PD-1 (programmed cell death-1) plus CTLA-4 (cytotoxic-T-lymphocyte associated antigen 4) blockade in patients with melanoma, the perspective of new synergistic immunotherapy combinations seems to be an important opportunity to improve outcomes for patients. In this article, we first focus on immunotherapy combinations that have shown their efficiency and that are currently approved in solid tumors. Then, we present a summary of emerging targets with reported pre-clinical efficacy and currently evaluated through ongoing clinical trials and other immunomodulatory molecules in the tumor microenvironment.

Combining Three Tyrosine Kinase Inhibitors: Drug Monitoring Is the Key.

A combination of tyrosine kinase inhibitors (TKIs) is likely to be a therapeutic option for numerous oncological situations due to high frequency of oncogenic addiction and progress in precision oncology. Non-small cell lung cancer (NSCLC) represents a subtype of tumors for which oncogenic drivers are frequently involved. To the best of our knowledge, we report the first case of a patient treated with three different TKIs. Osimertinib and crizotinib were administered concurrently for an epidermal growth factor receptor (EGFR)-mutated NSCLC developing a MET amplification as a resistance mechanism to osimertinib. Simultaneously, imatinib was administered for a metastatic gastrointestinal stromal tumor. The progression-free survival was 7 months for both tumors with this tritherapy. The use of therapeutic drug monitoring to assess plasma concentrations of each TKI was a powerful tool to manage the toxicity profile of this combination (creatine phosphokinase elevation) while preserving an optimal exposure to each TKI and treatment efficacy. We observed an imatinib over-exposition related to crizotinib introduction, probably explained by drug-drug interaction mediated by crizotinib enzymatic inhibition on cytochrome P-450 3A4. Posology adjustment due to therapeutic drug monitoring was probably involved in the good survival outcome of the patient. This tool should be used more routinely for patients treated by TKIs to prevent co-treatment interactions and, in particular, for patients receiving TKI combinations to obtain optimal therapeutic exposure and efficacy while reducing possible side-effects.

YWHAE loss of function causes a rare neurodevelopmental disease with brain abnormalities in human and mouse.

PURPOSE: Miller-Dieker syndrome is caused by a multiple gene deletion, including PAFAH1B1 and YWHAE. Although deletion of PAFAH1B1 causes lissencephaly unambiguously, deletion of YWHAE alone has not clearly been linked to a human disorder. METHODS: Cases with YWHAE variants were collected through international data sharing networks. To address the specific impact of YWHAE loss of function, we phenotyped a mouse knockout of Ywhae. RESULTS: We report a series of 10 individuals with heterozygous loss-of-function YWHAE variants (3 single-nucleotide variants and 7 deletions <1 Mb encompassing YWHAE but not PAFAH1B1), including 8 new cases and 2 follow-ups, added with 5 cases (copy number variants) from literature review. Although, until now, only 1 intragenic deletion has been described in YWHAE, we report 4 new variants specifically in YWHAE (3 splice variants and 1 intragenic deletion). The most frequent manifestations are developmental delay, delayed speech, seizures, and brain malformations, including corpus callosum hypoplasia, delayed myelination, and ventricular dilatation. Individuals with variants affecting YWHAE alone have milder features than those with larger deletions. Neuroanatomical studies in Ywhae-/- mice revealed brain structural defects, including thin cerebral cortex, corpus callosum dysgenesis, and hydrocephalus paralleling those seen in humans. CONCLUSION: This study further demonstrates that YWHAE loss-of-function variants cause a neurodevelopmental disease with brain abnormalities.

Efficacy and safety of nivolumab in bone metastases from renal cell carcinoma: Results of the GETUG-AFU26-NIVOREN multicentre phase II study.

INTRODUCTION: Bone metastases (BM) in renal cell carcinoma (RCC) are associated with a poor prognosis based on retrospective studies evaluating antiangiogenic agents. Few data are available regarding immune checkpoint inhibitors (ICI) in patients with bone metastatic RCC. NIVOREN is a multicentre prospective study in which patients were treated with nivolumab after the failure of antiangiogenic agents. We aim to assess the impact of BM on prognosis, and the efficacy and safety of nivolumab in patients enrolled in the NIVOREN trial. MATERIALS AND METHODS: All patients with BM at inclusion were included in our study. The primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS), objective response rate (ORR), safety, and skeletal-related events (SRE). RESULTS: Among 720 patients treated with nivolumab, 194 presented BM at inclusion. The median follow-up was 23.9 months. Median OS was 17.9 months in patients with BM versus 26.1 months in patients without BM (p = 0.0023). The difference was not statistically significant after adjustment (p = 0.0707). The median PFS was shorter in patients with BM even after adjustment (2.8 versus 4.6 months, p = 0.0045), as well as the ORR (14.8% versus 23.3%). SRE occurred for 36% of patients with BM. A post-hoc analysis evaluating the impact of bone-targeting agents (BTA) on SRE incidence showed a significant benefit of BTA on the incidence of SRE (OR = 0.367, CI95% [0.151-0.895]). CONCLUSION: Nivolumab is associated with shorter PFS, and lower ORR in RCC patients with BM. Our study suggests that BTA in association with immunotherapy decreases the incidence of SRE.

MDC1 maintains active elongation complexes of RNA polymerase II.

The role of MDC1 in the DNA damage response has been extensively studied; however, its impact on other cellular processes is not well understood. Here, we describe the role of MDC1 in transcription as a regulator of RNA polymerase II (RNAPII). Depletion of MDC1 causes a genome-wide reduction in the abundance of actively engaged RNAPII elongation complexes throughout the gene body of protein-encoding genes under unperturbed conditions. Decreased engaged RNAPII subsequently alters the assembly of the spliceosome complex on chromatin, leading to changes in pre-mRNA splicing. Mechanistically, the S/TQ domain of MDC1 modulates RNAPII-mediated transcription. Upon genotoxic stress, MDC1 promotes the abundance of engaged RNAPII complexes at DNA breaks, thereby stimulating nascent transcription at the damaged sites. Of clinical relevance, cancer cells lacking MDC1 display hypersensitivity to RNAPII inhibitors. Overall, we unveil a role of MDC1 in RNAPII-mediated transcription with potential implications for cancer treatment.

Expanding the Allelic Heterogeneity of ANO10-Associated Autosomal Recessive Cerebellar Ataxia.

Background and Objectives: The term autosomal recessive cerebellar ataxia (ARCA) encompasses a diverse group of heterogeneous degenerative disorders of the cerebellum. Spinocerebellar ataxia autosomal recessive 10 (SCAR10) is a distinct classification of cerebellar ataxia caused by variants in the ANO10 gene. Little is known about the molecular role of ANO10 or its role in disease. There is a wide phenotypic spectrum among patients, even among those with the same or similar genetic variants. This study aimed to characterize the molecular consequences of variants in ANO10 and determine their pathologic significance in patients diagnosed with SCAR10. Methods: We presented 4 patients from 4 families diagnosed with spinocerebellar ataxia with potential pathogenic variants in the ANO10 gene. Patients underwent either clinical whole-exome sequencing or screening of a panel of known neuromuscular disease genes. Effects on splicing were studied using reverse transcriptase PCR to analyze complementary DNA. Western blots were used to examine protein expression. Results: One individual who presented clinically at a much earlier age than typical was homozygous for an ANO10 variant (c.1864A > G [p.Met622Val]) that produces 2 transcription products by altering an exonic enhancer site. Two patients, both of Lebanese descent, had a homozygous intronic splicing variant in ANO10 (c.1163-9A > G) that introduced a cryptic splice site acceptor, producing 2 alternative transcription products and no detectable wild-type protein. Both these variants have not yet been associated with SCAR10. The remaining patient was found to have compound heterozygous variants in ANO10 previously associated with SCAR10 (c.132dupA [p.Asp45Argfs*9] and c.1537T > C [p.Cys513Arg]). Discussion: We presented rare pathogenic variants adding to the growing list of ANO10 variants associated with SCAR10. In addition, we described an individual with a much earlier age at onset than usually associated with ANO10 variants. This expands the phenotypic and allelic heterogeneity of ANO10-associated ARCA.

Further clinical and molecular characterization of an XLID syndrome associated with BRWD3 variants, a gene implicated in the leukemia-related JAK-STAT pathway.

BACKGROUND: Since the first description of a BRWD3-associated nonsydromic intellectual disability (ID) disorder in 2007, 21 additional families have been reported in the literature. METHODS: Using exome sequencing (ES) and international data sharing, we identified 14 additional unrelated individuals with pathogenic BRWD3 variants (12 males and 2 females, including one with skewed X-inactivation). We reviewed the 31 previously published cases in the literature with clinical data available, and describe the collective phenotypes of 43 males and 2 females, with 33 different BRWD3 variants. RESULTS: The most common features in males (excluding one patient with a mosaic variant) included ID (39/39 males), speech delay (24/25 males), postnatal macrocephaly (28/35 males) with prominent forehead (18/25 males) and large ears (14/26 males), and obesity (12/27 males). Both females presented with macrocephaly, speech delay, and epilepsy, while epilepsy was only observed in 4/41 males. Among the 28 variants with available segregation reported, 19 were inherited from unaffected mothers and 9 were de novo. CONCLUSION: This study demonstrates that the BRWD3-related phenotypes are largely non-specific, leading to difficulty in clinical recognition of this disorder. A genotype-first approach, however, allows for the more efficient diagnosis of the BRWD3-related nonsyndromic ID. The refined clinical features presented here may provide additional diagnostic assistance for reverse phenotyping efforts.

Asymmetric crying facies in an elderly, when a facial asymmetry is not a facial paralysis but a marker of possible congenital malformations: case report and review of the literature.

BACKGROUND: Facial asymmetry when crying at birth (then called asymmetric crying facies or ACF) or when smiling or speaking loudly in adulthood is the consequence of the agenesis or hypoplasia of the muscle of one of the labial commissures. This developmental disorder of complex mechanism is well known by pediatricians to be a warning sign for underlying developmental disorders of variable severity. CASE REPORT: An 80-year-old man with medical history of renal agenesis was hospitalized for a transient motor deficit of the right face and arm revealing a lacunar stroke. Clinical examination showed an isolated left facial asymmetry upon smiling or talking out loud which had been known since childhood and was not related to the stroke, leading to the diagnosis of ACF. Cardiac ultrasound revealed a patent foramen. Chromosomal investigations could not be performed. DISCUSSION AND CONCLUSION: ACF is a rare disorder that may conceal associated congenital disorders such as heart, skeletal, or renal malformations. Its causing mechanisms are to this day still poorly understood but may include a genetic component as shown by familial cases and the identification of 22q11.2 deletions or trisomy 18 in some patients. Knowledge of this disorder seems highly relevant for adult neurologists, first because of the differential diagnosis with facial palsy, but mostly because it will allow them to screen patients for other congenital disorders such as heart malformations. Conversely, cardiologists and cardiac surgeon may search for an ACF when faced with a patient with a congruent heart defect.

A New Presenilin-1 Missense Variant Associated With a Progressive Supranuclear Palsy-like Phenotype.

Early-onset forms of Alzheimer disease (AD) have been associated with pathogenic variants in the APP , PSEN1 , and PSEN2 genes. Mutations in presenilin-1 ( PSEN1 ) account for the majority of cases of autosomal dominant AD. Numerous phenotypes have been associated with PSEN1 -pathogenic variants, including cerebellar ataxia and spastic paraplegia. Here, we describe a patient with early-onset AD presenting with extrapyramidal symptoms and supranuclear gaze palsy, mimicking progressive supranuclear palsy.

Histone chaperone ASF1 mediates H3.3-H4 deposition in Arabidopsis.

Histone chaperones and chromatin remodelers control nucleosome dynamics, which are essential for transcription, replication, and DNA repair. The histone chaperone Anti-Silencing Factor 1 (ASF1) plays a central role in facilitating CAF-1-mediated replication-dependent H3.1 deposition and HIRA-mediated replication-independent H3.3 deposition in yeast and metazoans. Whether ASF1 function is evolutionarily conserved in plants is unknown. Here, we show that Arabidopsis ASF1 proteins display a preference for the HIRA complex. Simultaneous mutation of both Arabidopsis ASF1 genes caused a decrease in chromatin density and ectopic H3.1 occupancy at loci typically enriched with H3.3. Genetic, transcriptomic, and proteomic data indicate that ASF1 proteins strongly prefers the HIRA complex over CAF-1. asf1 mutants also displayed an increase in spurious Pol II transcriptional initiation and showed defects in the maintenance of gene body CG DNA methylation and in the distribution of histone modifications. Furthermore, ectopic targeting of ASF1 caused excessive histone deposition, less accessible chromatin, and gene silencing. These findings reveal the importance of ASF1-mediated histone deposition for proper epigenetic regulation of the genome.

Bi-allelic loss-of-function variants in TMEM147 cause moderate to profound intellectual disability with facial dysmorphism and pseudo-Pelger-Huët anomaly.

The transmembrane protein TMEM147 has a dual function: first at the nuclear envelope, where it anchors lamin B receptor (LBR) to the inner membrane, and second at the endoplasmic reticulum (ER), where it facilitates the translation of nascent polypeptides within the ribosome-bound TMCO1 translocon complex. Through international data sharing, we identified 23 individuals from 15 unrelated families with bi-allelic TMEM147 loss-of-function variants, including splice-site, nonsense, frameshift, and missense variants. These affected children displayed congruent clinical features including coarse facies, developmental delay, intellectual disability, and behavioral problems. In silico structural analyses predicted disruptive consequences of the identified amino acid substitutions on translocon complex assembly and/or function, and in vitro analyses documented accelerated protein degradation via the autophagy-lysosomal-mediated pathway. Furthermore, TMEM147-deficient cells showed CKAP4 (CLIMP-63) and RTN4 (NOGO) upregulation with a concomitant reorientation of the ER, which was also witnessed in primary fibroblast cell culture. LBR mislocalization and nuclear segmentation was observed in primary fibroblast cells. Abnormal nuclear segmentation and chromatin compaction were also observed in approximately 20% of neutrophils, indicating the presence of a pseudo-Pelger-Huët anomaly. Finally, co-expression analysis revealed significant correlation with neurodevelopmental genes in the brain, further supporting a role of TMEM147 in neurodevelopment. Our findings provide clinical, genetic, and functional evidence that bi-allelic loss-of-function variants in TMEM147 cause syndromic intellectual disability due to ER-translocon and nuclear organization dysfunction.