Zhou A et al., Human Genetics and Genomics Advances - Comparing LD‑pruning, COJO, SuSiE and PCA in haptoglobin (HP) cis‑region data, the study finds including non‑lead variants substantially increases variance explained (R2) and MR precision.

Study Highlights:
The study analyzed circulating haptoglobin (HP) using Fenland protein GWAS summary statistics with LD from UK Biobank, compared four variant selection methods (modified LD‑pruning, COJO, SuSiE, PCA), and extended results with simulations and 15 additional gene regions. In the HP region, incorporating non‑lead variants produced a median proportional gain in R2 of 145.1% and a median reduction in MR standard error of 36.3% relative to the lead variant alone. In simulations with one or two causal variants the methods recovered the expected genetic variance (≈40%) and, when causal variants were removed, non‑lead‑inclusive methods recovered more variance than lead‑only. The functional implication supported by the data is that including correlated non‑lead variants can materially increase instrument strength and precision in cis‑MR, but may raise risks of pleiotropy and numerical instability.

Conclusion:
Variant selection methods that incorporate correlated non‑lead variants reliably improve instrument strength (R2) and MR precision in cis‑MR compared with the lead‑variant‑only approach; comparisons with the lead variant are advised to detect instability.

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Reference:
Zhou A, Karhunen V, Tian H, Pott J, Patel A, Slob EAW, Burgess S. Variant selection to maximize variance explained in cis-Mendelian randomization. Human Genetics and Genomics Advances. 2026 Apr 9;7:100573. https://doi.org/10.1016/j.xhgg.2026.100573.

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Lambton J et al., The American Journal of Human Genetics - Bi-allelic ATG12 variants disrupt ATG12‑ATG5 conjugation and LC3 lipidation, impairing autophagy in patient cells and model systems and causing cerebellar vermis hypoplasia.

Study Highlights:
The study characterized six affected individuals with bi-allelic ATG12 variants using patient fibroblasts, HeLa ATG12 knockout complementation, yeast complementation, and CRISPR zebrafish models. Methods included WES/WGS and Sanger sequencing, immunoblotting, LC3/p62 flux assays, HaloTag-LC3 processing, LDH sequestration, AlphaFold-Multimer structural modeling, yeast GFP-Atg8 assays, and zebrafish behavioral and imaging assays. Structural modeling and biochemical data indicate variants map to ATG12 interfaces with ATG5 and ATG3, destabilize ATG12 or its conjugate with ATG5, reduce LC3/Atg8 lipidation and autophagic flux in a variant-dependent manner. Functionally, ATG12 disruption associates with neurodevelopmental phenotypes including cerebellar vermis hypoplasia, ataxia and seizures in humans, and causes growth, brain-structure and locomotor defects with reduced survival in zebrafish.

Conclusion:
Bi-allelic ATG12 variants impair ATG12 function and autophagy, producing a recessive neurodevelopmental disorder marked by cerebellar vermis hypoplasia and neurological deficits.

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Reference:
Lambton J, Asano S, Huang Y, Suomi F, Eguchi T, Petree C, Huang K, Prigent M, Imam A, McCorvie TJ, Warren D, Hobson E, McCullagh H, Misceo D, Bjerre A, Smeland MF, Klingenberg C, Frengen E, Naik S, Ryan G, Sudarsanam A, Foster K, Vasudevan P, Samanta R, Rahman F, Maqbool S, Udani V, Efthymiou S, Houlden H, McFarland R, Collier JJ, Maroofian R, Yue WW, Varshney GK, Klionsky DJ, Legouis R, McWilliams TG, Mizushima N, Oláhová M, Alston CL, Taylor RW. Bi-allelic ATG12 variants impair autophagy and cause a neurodevelopmental disorder. The American Journal of Human Genetics. 2026 May 7;113:1–18. https://doi.org/10.1016/j.ajhg.2026.03.002

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Strand LG et al., PNAS - In C. elegans germline, the deubiquitinase DUO-1 is required for assembly and active maintenance of the synaptonemal complex and REC-8 cohesin, preventing RAD-51 accumulation and ensuring diakinesis compaction.

Study Highlights:
Using C. elegans germline as a developmental timecourse model, the authors combined cytological analyses (immunofluorescence, FISH, RAD-51/MSH-5/COSA-1 staining), temporally controlled auxin-inducible degron (AID) depletion, and TurboID proximity labeling with LC–MS to probe DUO-1 function. Loss or acute depletion of DUO-1 impairs SC assembly, leads to progressive axis/SC instability, depletion of REC-8 cohesin from chromosomes, hyperaccumulation of RAD-51-marked early DSB repair intermediates, and premature sister-chromatid separation. TurboID identifies PARG-1 and cohesin/HORMAD components as proximal partners and DUO-1::GFP localizes to nucleoplasm and a subset of chromosome axes, most prominently in late pachytene/early diplotene. Temporal AID experiments show DUO-1 is required continuously for early SC assembly, late-pachytene SC maintenance, and rapid preservation of diakinesis chromosome compaction, implying an active maintenance role for DUO-1 in preserving chromosome architecture during meiotic prophase.

Conclusion:
DUO-1 is continuously required throughout meiotic prophase in C. elegans to promote assembly and maintain stability of chromosome axes and synaptonemal complexes, protect REC-8 cohesin distribution, limit accumulation of early DSB repair intermediates, and ensure late-prophase chromosome compaction.

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Reference:
Strand LG, Choi CP, McCoy S, Nsamba ET, Silva N, Villeneuve AM. Active maintenance of meiosis-specific chromosome structures in Caenorhabditis elegans by the deubiquitinase DUO-1. Proc. Natl. Acad. Sci. U.S.A. 2026;123(12):e2532671123. https://doi.org/10.1073/pnas.2532671123

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• (00:00:00) - The architectural worksite of life
• (00:05:24) - The genetic disaster of Meotic mutants
• (00:10:49) - The Duplicity of Probes
• (00:16:29) - How does DNA repair become so fragile as we grow?

Lawrence et al., Focus on single-gene effects limits discovery and interpretation of complex-trait-associated variants. The American Journal of Human Genetics 113 - Using a cis-principal-component (pcQTL) approach in human GTEx tissues, the authors uncover novel multi-gene regulatory variants and 33% more GWAS colocalizations than single-gene eQTLs.

Study Highlights:
The study analyzes 13 human GTEx tissues and identifies clusters of co-expressed neighboring genes, then applies PCA to cluster expression and maps cis-principal-component QTLs (pcQTLs). pcQTL discovery and fine-mapping used SuSiE and TensorQTL permutation-based FDR to identify an average of ~1,396 pcQTLs per tissue, ~27% of which were not found by single-gene eQTL mapping. pcQTLs tend to represent smaller effects distributed across multiple genes in a cluster and often colocalize with GWAS hits missed by single-gene methods. Functionally, pcQTLs increased GWAS colocalizations by 33%, highlighting multi-gene regulatory proxitropy as a source of complex-trait-associated variation.

Conclusion:
Cis-multi-gene pcQTL mapping uncovers novel regulatory loci and increases GWAS colocalizations compared with single-gene analyses, demonstrating that multi-gene approaches improve detection and interpretation of complex-trait-associated variants.

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Reference:
Lawrence, K.A., Gjorgjieva, T., Nachun, D., and Montgomery, S.B. (2026). Focus on single-gene effects limits discovery and interpretation of complex-trait-associated variants. The American Journal of Human Genetics 113, 1–10. https://doi.org/10.1016/j.ajhg.2026.02.022

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• (00:00:00) - Deep Dive: The genome's interconnected networks
• (00:05:27) - The Shared Signal of Genomic Science
• (00:11:15) - Single gene mapping fails to explain complex traits
• (00:18:13) - Understanding the genetics of human diseases
• (00:20:39) - Beyond one gene

Farnung J et al., The E3 ubiquitin ligase mechanism specifying targeted microRNA degradation. Nature ( - Cryo-EM and biochemical reconstitution reveal how the ZSWIM8–CUL3 E3 ligase recognizes human AGO2–miRNA–trigger complexes to polyubiquitylate AGO and drive targeted microRNA degradation.

Study Highlights:
Using purified human proteins and cellular assays, the authors combined cryo-EM (3.1 Å), in vitro ubiquitylation, co-immunoprecipitation and sRNA-seq to dissect TDMD. Cryo-EM shows a dimeric ZSWIM8 that forms an asymmetric clamp around AGO2–miR-7–CYRANO, engaging the MID, N and PAZ domains and embracing trigger RNA flanks. Biochemical reconstitution demonstrates that ZSWIM8–CUL3 together with ARIH1 polyubiquitylates surface lysines of AGO only when the miRNA is paired to a trigger that vacates the PAZ pocket and imposes a specific RNA trajectory. Functionally, these multivalent RNA–RNA, RNA–protein and protein–protein interactions establish a two-RNA-factor authentication mechanism that explains TDMD selectivity and indicates ZSWIM8 can destabilize extensively trimmed miRNAs.

Conclusion:
ZSWIM8–CUL3 recognizes a trigger-induced AGO–miRNA conformation via multivalent interactions—including sensing a vacated PAZ pocket and flanking trigger RNA—to direct ARIH1-dependent polyubiquitylation of AGO and execute TDMD.

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Reference:
Farnung J., Slobodyanyuk E., Wang P.Y., Blodgett L.W., Lin D.H., von Gronau S., Schulman B.A. & Bartel D.P. The E3 ubiquitin ligase mechanism specifying targeted microRNA degradation. Nature (2026). https://doi.org/10.1038/s41586-026-10232-0

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Norgren J et al., JAMA Network Open - Population-based SNAC-K study finds higher meat consumption associated with slower cognitive decline and lower dementia risk in APOE ε3/ε4 and ε4/ε4 older adults.

Study Highlights:
Using the Swedish National Study on Aging and Care–Kungsholmen (SNAC-K) cohort of older adults and repeated validated food-frequency questionnaires, the authors applied panel data analyses with linear regression for cognitive trajectories and Fine and Gray models for dementia incidence. Higher total meat consumption (top vs bottom quintile) in APOE ε3/ε4 and ε4/ε4 participants was associated with better 10-year global cognitive trajectories (β = 0.32) and lower dementia risk (sHR = 0.45). The processed-to-total meat ratio was associated with higher dementia risk (sHR = 1.14) without APOE interaction. Post hoc vitamin B12 analyses suggested APOE-specific differences in nutrient uptake that could help explain the genotype-specific associations.

Conclusion:
Higher meat consumption was associated with slower cognitive decline and reduced dementia incidence among APOE ε3/ε4 and ε4/ε4 carriers, such that the expected excess risk in these genotypes was not observed at high intake levels.

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Reference:
Norgren J, Carballo-Casla A, Grande G, et al. Meat Consumption and Cognitive Health by APOE Genotype. JAMA Network Open. 2026;9(3):e266489. https://doi.org/10.1001/jamanetworkopen.2026.6489

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Johnson MB et al., The American Journal of Human Genetics - Bi-allelic variants in snRNAs RNU6ATAC and RNU4ATAC cause infancy-onset autoimmune diabetes in humans, with RNA-seq showing U12 intron retention and impaired B cell development.

Study Highlights:
In human infants with early-onset diabetes and immune dysregulation, the authors used genome sequencing, RNA-seq, DNA methylation deconvolution, WGCNA, Sanger sequencing, and flow cytometry to define a genetic syndrome. They identified 19 individuals with bi-allelic RNU6ATAC or RNU4ATAC variants and RNA-seq revealed significant U12 intron retention in 274 genes, 94% of which are known U12-intron-containing genes. Multi-omic analyses and targeted immune profiling showed reduced naive B cells and abnormal B cell maturation. Half of tested individuals were GADA-positive, supporting an autoimmune mechanism for the diabetes in these snRNA spliceosome disorders.

Conclusion:
Bi-allelic pathogenic variants in RNU6ATAC cause early-onset autoimmune diabetes with immune dysregulation and bi-allelic RNU4ATAC variants extend RNU4ATAC-opathy to include infancy-onset autoimmune diabetes.

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Reference:
Johnson MB, Russ-Silsby J, Blair PA, Govier M, Bonfield G, Domingo-Vila C, EXE-T1D consortium, ATAC clinical consortium, Wakeling MN, Oram RA, Flanagan SE, Tree TIM, Patel KA, Hattersley AT, De Franco E. Bi-allelic variants in the non-protein-coding minor spliceosome components RNU6ATAC and RNU4ATAC cause syndromic monogenic autoimmune diabetes. The American Journal of Human Genetics. 2026 Apr 2;113:1–11. https://doi.org/10.1016/j.ajhg.2026.02.017

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Koga T et al., et al. A complete set of canonical nucleobases in the carbonaceous asteroid (162173) Ryugu. Nature Astronomy ( - Ryugu asteroid samples analyzed by HPLC/ESI-HRMS reveal all five canonical nucleobases (adenine, guanine, cytosine, thymine, uracil) and distribution linked to ammonia.

Study Highlights:
The team analysed Ryugu aggregate samples A0480 and C0370 and the Orgueil meteorite using water and HCl extraction followed by HPLC/ESI-HRMS, CE-HRMS and nano-EA/IRMS. They identified all five canonical nucleobases and measured total nucleobase concentrations (C0370 = 1,577 pmol g−1) and purine-to-pyrimidine (Pu/Py) ratios of ~1.1–1.2 in Ryugu contrasted with 0.099 in Orgueil and 3.4 in Murchison. A strong negative correlation (R2=0.89) between Pu/Py ratios and ammonia across Ryugu, Bennu and Orgueil implies ammonia availability influenced nucleobase formation pathways. The results support widespread abiotic nucleobase synthesis in carbonaceous parent bodies and potential delivery of diverse prebiotic molecules to early Earth.

Conclusion:
All five canonical nucleobases are present in Ryugu samples and their purine-to-pyrimidine distributions, which correlate with ammonia, indicate shared but environment-dependent formation pathways on carbonaceous parent bodies.

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Reference:
Koga T., Ogawa N. O., Ohkouchi N., Oba Y., Takano Y., Naraoka H., Sasaki K., Sato H., Yoshimura T. et al. A complete set of canonical nucleobases in the carbonaceous asteroid (162173) Ryugu. Nature Astronomy (2026). https://doi.org/10.1038/s41550-026-02791-z

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