Catherine M Choueiri, Jarred Lau, Emily O'Connor, Alicia DiBattista, Brittany Y Wong, Sally Spendiff, Rita Horvath, Izabella Pena, Alexander MacKenzie, Hanns Lochmüller
{"title":"Development of a riboflavin-responsive model of riboflavin transporter deficiency in zebrafish.","authors":"Catherine M Choueiri, Jarred Lau, Emily O'Connor, Alicia DiBattista, Brittany Y Wong, Sally Spendiff, Rita Horvath, Izabella Pena, Alexander MacKenzie, Hanns Lochmüller","doi":"10.1093/hmg/ddae171","DOIUrl":"https://doi.org/10.1093/hmg/ddae171","url":null,"abstract":"<p><p>Riboflavin transporter deficiency (RTD) is a rare and progressive neurodegenerative disease resulting from the disruption of RFVT2- and RFVT3- mediated riboflavin transport caused by biallelic mutations in SLC52A2 and SLC52A3, respectively. The resulting impaired mitochondrial metabolism leads to sensorimotor neurodegeneration and symptoms including muscle weakness, respiratory difficulty, and sensorineural deafness. Although over 70% of patients with RTD improve following high-dose riboflavin supplementation, remaining patients either stabilise or continue to deteriorate. This may be due to the rapid excretion of central nervous system (CNS) riboflavin by organic anion transporter 3 (OAT-3), highlighting the need for alternative or supplemental RTD treatments. Probenecid is a promising therapeutic candidate for RTD due to its known inhibitory effect on OAT-3. Therefore, this study aimed to generate morpholino-mediated knockdowns of human SLC52A3 ortholog slc52a3 in zebrafish larvae for use in therapeutic screening of riboflavin and probenecid. Knockdown of slc52a3 resulted in an RTD-like phenotype indicative of altered neurodevelopment, hearing loss, and reduced mobility. This RTD-like phenotype overlaps with the phenotype of CRISPR/Cas9-mediated knockout of slc52a3 in zebrafish, is maintained following slc52a3 morpholino + p53 morpholino co-injection, and is rescued following slc52a3 morpholino + human SLC52A3 mRNA co-injection, indicating specificity of the knockdown. Riboflavin treatment alone ameliorates locomotor activity and hearing ability in slc52a3 morphants. Riboflavin and probenecid co-treatment provides an additional small benefit to hearing but not to locomotion. Our findings demonstrate that this model recapitulates both the RTD phenotype and the riboflavin-responsiveness of RTD patients, and possible therapeutic benefit conferred by probenecid warrants further investigation.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinyu Li, Chuo Peng, Hongyu Liu, Mingjie Dong, Shujuan Li, Weixin Liang, Xia Li, Jing Bai
{"title":"Constructing methylation-driven ceRNA networks unveil tumor heterogeneity and predict patient prognosis.","authors":"Xinyu Li, Chuo Peng, Hongyu Liu, Mingjie Dong, Shujuan Li, Weixin Liang, Xia Li, Jing Bai","doi":"10.1093/hmg/ddae176","DOIUrl":"https://doi.org/10.1093/hmg/ddae176","url":null,"abstract":"<p><p>Cancer development involves a complex interplay between genetic and epigenetic factors, with emerging evidence highlighting the pivotal role of competitive endogenous RNA (ceRNA) networks in regulating gene expression. However, the influence of ceRNA networks by aberrant DNA methylation remains incompletely understood. In our study, we proposed DMceNet, a computational method to characterize the effects of DNA methylation on ceRNA regulatory mechanisms and apply it across eight prevalent cancers. By integrating methylation and transcriptomic data, we constructed methylation-driven ceRNA networks and identified a dominant role of lncRNAs within these networks in two key ways: (i) 17 cancer-shared differential methylation lncRNAs (DMlncs), including PVT1 and CASC2, form a Common Cancer Network (CCN) affecting key pathways such as the G2/M checkpoint, and (ii) 24 cancer-specific DMlncs construct unique ceRNA networks for each cancer type. For instance, in LUAD and STAD, hypomethylation drives DMlncs like PCAT6 and MINCR, disrupting the Wnt signaling pathway and apoptosis. We further investigated the characteristics of these methylation-driven ceRNA networks at the cellular level, revealing how methylation-driven dysregulation varies across distinct cell populations within the tumor microenvironment. Our findings also demonstrate the prognostic potential of cancer-specific ceRNA relationships, highlighting their relevance in predicting patient survival outcomes. This integrated transcriptomic and epigenomic analysis provides new insights into cancer biology and regulatory mechanisms.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142739499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recruitment of chromatin remodelers by XIST B-repeat region is variably dependent on HNRNPK.","authors":"Maria Jose Navarro-Cobos, Carolyn J Brown","doi":"10.1093/hmg/ddae173","DOIUrl":"https://doi.org/10.1093/hmg/ddae173","url":null,"abstract":"<p><p>X-chromosome inactivation is triggered by the long non-coding RNA XIST, whose structure is characterized by tandem repeats that modularly recruit different proteins and chromatin remodelers. Previously, we reported that the addition of the mouse PID region to a transgene with human repeat regions A, F and E (miniXIST; 5.1 kb) enabled binding of HNRNPK and also enabled the induction of silencing and recruitment of H3K27me3, UbH2A and H4K20me1, but only partially. As the 680 bp PID region enabled so many features of inactivation, we hypothesized that augmenting the PID with more mouse or human sequences rich in CCC motifs would allow us to design a short transgene which was as effective as Full XIST. Three new transgenes using the A, F and E human domains as a backbone were tested for ability to induce silencing and heterochromatic mark recruitment. The all human-derived BhB-BhB transgene (4.9 kb) was as good as our previous miniXIST, suggesting that these domains are the human equivalent of the mouse PID region. A PID-PID transgene (5.8 kb) was not statistically different from Full XIST and could be potentially used for chromosome therapy. Adding BhB to PID (BhB-PID, 5.4 kb) had an intermediate efficacy compared to the other two transgenes, suggesting that the most important component for silencing and heterochromatic mark recruitment is the number of CCC motifs, not the species of origin. Finally, we created a heterozygous HNRNPK deletion and observed a disproportionate impact on HNRNPK and UbH2A recruitment to XIST, reflecting complex roles for the PID and HNRNPK in X-chromosome inactivation.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142715976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Asmer Aliyeva, Claudia D Lennon, John D Cleary, Hannah K Shorrock, J Andrew Berglund
{"title":"Dysregulation of alternative splicing is a transcriptomic feature of patient-derived fibroblasts from CAG repeat expansion spinocerebellar ataxias.","authors":"Asmer Aliyeva, Claudia D Lennon, John D Cleary, Hannah K Shorrock, J Andrew Berglund","doi":"10.1093/hmg/ddae174","DOIUrl":"https://doi.org/10.1093/hmg/ddae174","url":null,"abstract":"<p><p>The spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of rare dominantly inherited neurodegenerative diseases characterized by progressive ataxia. The most common mutation seen across the SCAs is a CAG repeat expansion, causative for SCA1, 2, 3, 6, 7, 12 and 17. We recently identified dysregulation of alternative splicing as a novel, presymptomatic transcriptomic hallmark in mouse models of SCAs 1, 3 and 7. In order to understand if dysregulation of alternative splicing is a transcriptomic feature of patient-derived cell models of CAG SCAs, we performed RNA sequencing and transcriptomic analysis in patient-derived fibroblast cell lines of SCAs 1, 3 and 7. We identified widespread and robust dysregulation of alternative splicing across all CAG expansion SCA lines investigated, with disease relevant pathways affected, such as microtubule-based processes, transcriptional regulation, and DNA damage and repair. Novel disease-relevant alternative splicing events were validated across patient-derived fibroblast lines from multiple CAG SCAs and CAG containing reporter cell lines. Together this study demonstrates that dysregulation of alternative splicing represents a novel and shared pathogenic process in CAG expansion SCA1, 3 and 7 and can potentially be used as a biomarker across patient models of this group of devastating neurodegenerative diseases.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142715972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anneliza Andreadi, Thomas M Hallam, Vicky Brocklebank, Scott J Sharp, Patrick R Walsh, Tom Southerington, Marco Hautalahti, David H Steel, Andrew J Lotery, Claire L Harris, Kevin J Marchbank, David Kavanagh, Amy V Jones
{"title":"The role of complement factor I rare genetic variants in age related macular degeneration in Finland.","authors":"Anneliza Andreadi, Thomas M Hallam, Vicky Brocklebank, Scott J Sharp, Patrick R Walsh, Tom Southerington, Marco Hautalahti, David H Steel, Andrew J Lotery, Claire L Harris, Kevin J Marchbank, David Kavanagh, Amy V Jones","doi":"10.1093/hmg/ddae165","DOIUrl":"https://doi.org/10.1093/hmg/ddae165","url":null,"abstract":"<p><p>Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the developed world. The alternative pathway (AP) of complement has been linked to the pathogenesis of AMD. In particular, rare variants (RVs) in the complement factor I (CFI) gene encoding the Factor I (FI) protein confer increased AMD risk. The prevalence of CFI RVs are well characterised in European AMD, however little is known about other populations. The Finnish population underwent genetic restriction events which have skewed allele frequencies in unexpected ways. A series of novel or enriched CFI RVs were identified in individuals with dry AMD from the Finnish Biobank Cooperative (FINBB), but the relationship between these genotypes and contribution to disease was unclear. Understanding how RVs impact the ability of FI to regulate the complement system is important to inform mechanistic understanding for how different genotypes contribute to disease development. To explore this a series of in vitro assays were used to functionally characterise the protein products of 3 CFI RVs enriched in FINBB dry AMD, where no prior data were available. The G547R variant resulted in almost complete loss of both classical pathway and AP regulatory potential. The c.982 g>a variant encoding G328R FI perturbed an exon splice enhancer site which resulted in exon skipping and a premature stop codon in vitro and low levels of FI in vivo. Despite detailed analysis no defect in levels or function was demonstrated in T107A. Functional characterization of all Finnish CFI RVs in the cohort allowed us to demonstrate that in Finnish dry AMD, collectively the type 1 CFI RVs (associated with FI haploinsufficiency) were significantly enriched with odds ratio (ORs) of 72.6 (95% confidence interval; CI 16.92 to 382.1). Meanwhile, type 2 CFI RVs (associated with FI dysfunction) collectively conferred a significant OR of 4.97 (95% CI 1.522 to 15.74), and non-impaired or normal CFI RV collectively conferred an of OR 3.19 (95% CI 2.410 to 4.191) although this was driven primarily by G261D. Overall, this study for the first time determined the ORs and functional effect for all CFI RVs within a Geographic Atrophy (GA) cohort, enabling calculations of combined risk scores that underline the risk conferred by type 1 and 2 CFI RVs in GA/AMD.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142710031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Benjamin G Faber, Monika Frysz, Jaiyi Zheng, Huandong Lin, Kaitlyn A Flynn, Raja Ebsim, Fiona R Saunders, Rhona Beynon, Jennifer S Gregory, Richard M Aspden, Nicholas C Harvey, Claudia Lindner, Timothy Cootes, David M Evans, George Davey Smith, Xin Gao, Sijia Wang, John P Kemp, Jonathan H Tobias
{"title":"The genetic architecture of hip shape and its role in the development of hip osteoarthritis and fracture.","authors":"Benjamin G Faber, Monika Frysz, Jaiyi Zheng, Huandong Lin, Kaitlyn A Flynn, Raja Ebsim, Fiona R Saunders, Rhona Beynon, Jennifer S Gregory, Richard M Aspden, Nicholas C Harvey, Claudia Lindner, Timothy Cootes, David M Evans, George Davey Smith, Xin Gao, Sijia Wang, John P Kemp, Jonathan H Tobias","doi":"10.1093/hmg/ddae169","DOIUrl":"https://doi.org/10.1093/hmg/ddae169","url":null,"abstract":"<p><strong>Objectives: </strong>Hip shape is thought to be an important causal risk factor for hip osteoarthritis and fracture. We aimed to identify genetic determinants of hip shape and use these to assess causal relationships with hip osteoarthritis.</p><p><strong>Methods: </strong>Statistical hip shape modelling was used to derive 10 hip shape modes (HSMs) from DXA images in UK Biobank and Shanghai Changfeng cohorts (ntotal = 43 485). Genome-wide association study meta-analyses were conducted for each HSM. Two-sample Mendelian randomisation (MR) was used to estimate causal effects between HSM and hip osteoarthritis using hip fracture as a positive control.</p><p><strong>Results: </strong>Analysis of the first 10 HSMs identified 203 independent association signals (P < 5 × 10-9). Hip shape SNPs were also associated (P < 2.5 × 10-4) with hip osteoarthritis (n = 26) and hip fracture (n = 4). Fine mapping implicated SMAD3 and PLEC as candidate genes that may be involved in the development of hip shape and hip osteoarthritis. MR analyses suggested there was no causal effect between any HSM and hip osteoarthritis, however there was evidence that HSM2 (more obtuse neck-shaft angle) and HSM4 (wider femoral neck) have a causal effect on hip fracture (ORIVW method 1.27 [95% CI 1.12-1.44], P = 1.79 × 10-4 and ORIVW 0.74 [0.65-0.84], P = 7.60 × 10-6 respectively).</p><p><strong>Conclusions: </strong>We report the largest hip shape GWAS meta-analysis that identifies hundreds of novel loci, some of which are also associated with hip osteoarthritis and hip fracture. MR analyses suggest hip shape may not cause hip osteoarthritis but is implicated in hip fractures. Consequently, interventions targeting hip shape in older adults to prevent hip osteoarthritis may prove ineffective.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142686895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rudradip Pattanayak, Roschongporn Ekkatine, Chad M Petit, Talene A Yacoubian
{"title":"14-3-3 phosphorylation inhibits 14-3-3θ's ability to regulate LRRK2 kinase activity and toxicity.","authors":"Rudradip Pattanayak, Roschongporn Ekkatine, Chad M Petit, Talene A Yacoubian","doi":"10.1093/hmg/ddae142","DOIUrl":"10.1093/hmg/ddae142","url":null,"abstract":"<p><p>LRRK2 mutations are among the most common genetic causes for Parkinson's disease (PD), and toxicity is associated with increased kinase activity. 14-3-3 proteins are key interactors that regulate LRRK2 kinase activity. Phosphorylation of the 14-3-3θ isoform at S232 is dramatically increased in human PD brains. Here we investigate the impact of 14-3-3θ phosphorylation on its ability to regulate LRRK2 kinase activity. Both wildtype and the non-phosphorylatable S232A 14-3-3θ mutant reduced the kinase activity of wildtype and G2019S LRRK2, whereas the phosphomimetic S232D 14-3-3θ mutant had minimal effects on LRRK2 kinase activity, as determined by measuring autophosphorylation at S1292 and T1503 and Rab10 phosphorylation. However, wildtype and both 14-3-3θ mutants similarly reduced the kinase activity of the R1441G LRRK2 mutant. 14-3-3θ phosphorylation did not promote global dissociation with LRRK2, as determined by co-immunoprecipitation and proximal ligation assays. 14-3-3s interact with LRRK2 at several phosphorylated serine/threonine sites, including T2524 in the C-terminal helix, which can fold back to regulate the kinase domain. Interaction between 14-3-3θ and phosphorylated T2524 LRRK2 was important for 14-3-3θ's ability to regulate kinase activity, as wildtype and S232A 14-3-3θ failed to reduce the kinase activity of G2019S/T2524A LRRK2. Finally, we found that the S232D mutation failed to protect against G2019S LRRK2-induced neurite shortening in primary cultures, while the S232A mutation was protective. We conclude that 14-3-3θ phosphorylation destabilizes the interaction of 14-3-3θ with LRRK2 at T2524, which consequently promotes LRRK2 kinase activity and toxicity.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":"2071-2083"},"PeriodicalIF":3.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11578116/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142345736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peyton E Fuller, Victoria L Collis, Pallavi Sharma, Angelina M Burkett, Shaoteng Wang, Kyle A Brown, Nick Weir, Chris N Goulbourne, Ralph A Nixon, Thomas A Longden, Todd D Gould, Mervyn J Monteiro
{"title":"Pathophysiologic abnormalities in transgenic mice carrying the Alzheimer disease PSEN1 Δ440 mutation.","authors":"Peyton E Fuller, Victoria L Collis, Pallavi Sharma, Angelina M Burkett, Shaoteng Wang, Kyle A Brown, Nick Weir, Chris N Goulbourne, Ralph A Nixon, Thomas A Longden, Todd D Gould, Mervyn J Monteiro","doi":"10.1093/hmg/ddae139","DOIUrl":"10.1093/hmg/ddae139","url":null,"abstract":"<p><p>Mutations in PSEN1 were first discovered as a cause of Alzheimer's disease (AD) in 1995, yet the mechanism(s) by which the mutations cause disease still remains unknown. The generation of novel mouse models assessing the effects of different mutations could aid in this endeavor. Here we report on transgenic mouse lines made with the Δ440 PSEN1 mutation that causes AD with parkinsonism:- two expressing the un-tagged human protein and two expressing a HA-tagged version. Detailed characterization of these lines showed that Line 305 in particular, which expresses the untagged protein, develops age-dependent memory deficits and pathologic features, many of which are consistent with features found in AD. Key behavioral and physiological alterations found in the novel 305 line included an age-dependent deficit in spontaneous alternations in the Y-maze, a decrease in exploration of the center of an open field box, a decrease in the latency to fall on a rotarod, a reduction in synaptic strength and pair-pulse facilitation by electrophysiology, and profound alterations to cerebral blood flow regulation. The pathologic alterations found in the line included, significant neuronal loss in the hippocampus and cortex, astrogliosis, and changes in several proteins involved in synaptic and mitochondrial function, Ca2+ regulation, and autophagy. Taken together, these findings suggest that the transgenic lines will be useful for the investigation of AD pathogenesis.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":"2051-2070"},"PeriodicalIF":3.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11578115/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142345738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Priyanka Sandal, Chian Ju Jong, Ronald A Merrill, Grace J Kollman, Austin H Paden, Eric G Bend, Jennifer Sullivan, Rebecca C Spillmann, Vandana Shashi, Anneke T Vulto-van Silfhout, Rolph Pfundt, Bert B A de Vries, Pan P Li, Louise S Bicknell, Stefan Strack
{"title":"De novo missense variants in the PP2A regulatory subunit PPP2R2B in a neurodevelopmental syndrome: potential links to mitochondrial dynamics and spinocerebellar ataxias.","authors":"Priyanka Sandal, Chian Ju Jong, Ronald A Merrill, Grace J Kollman, Austin H Paden, Eric G Bend, Jennifer Sullivan, Rebecca C Spillmann, Vandana Shashi, Anneke T Vulto-van Silfhout, Rolph Pfundt, Bert B A de Vries, Pan P Li, Louise S Bicknell, Stefan Strack","doi":"10.1093/hmg/ddae166","DOIUrl":"https://doi.org/10.1093/hmg/ddae166","url":null,"abstract":"<p><p>The heterotrimeric protein phosphatase 2A (PP2A) complex catalyzes about half of Ser/Thr dephosphorylations in eukaryotic cells. A CAG repeat expansion in the neuron-specific protein PP2A regulatory subunit PPP2R2B gene causes spinocerebellar ataxia type 12 (SCA12). We established five monoallelic missense variants in PPP2R2B (four confirmed as de novo) as a cause of intellectual disability with developmental delay (R149P, T246K, N310K, E37K, I427T). In addition to moderate to severe intellectual disability and developmental delay, affected individuals presented with seizures, microcephaly, aggression, hypotonia, as well as broad-based or stiff gait. We used biochemical and cellular assays, including a novel luciferase complementation assay to interrogate PP2A holoenzyme assembly and activity, as well as deregulated mitochondrial dynamics as possible pathogenic mechanisms. Cell-based assays documented impaired ability of PPP2R2B missense variants to incorporate into the PP2A holoenzyme, localize to mitochondria, induce fission of neuronal mitochondria, and dephosphorylate the mitochondrial fission enzyme dynamin-related protein 1. AlphaMissense-based pathogenicity prediction suggested that an additional seven unreported missense variants may be pathogenic. In conclusion, our studies identify loss-of-function at the PPP2R2B locus as the basis for syndromic intellectual disability with developmental delay. They also extend PPP2R2B-related pathologies from neurodegenerative (SCA12) to neurodevelopmental disorders and suggests that altered mitochondrial dynamics may contribute to mechanisms.</p>","PeriodicalId":13070,"journal":{"name":"Human molecular genetics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142675668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}