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Emil Uffelmann

@euffelmann.bsky.social
100 followers 192 following 64 posts

Statistical genetics

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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
I recently discovered Spotify DJ, which does exactly that I think support.spotify.com/de-en/articl...
support.spotify.com
DJ - Spotify
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Michel Nivard @michelnivard.bsky.social · 21/09/2026
This is quite useful for genetics, but dependent on whether any of the inputs are genetics specific, might also be useful for psychologists and social scientists. Go from nagelkerke’s R2 to the R2 on the liability scale ( a latent variable that underlies your binary outcome)
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
Thanks! I think it should work for any predictor that behaves like a PGS (that is, normally distributed and linearly related to the liability)
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
📄 Preprint: www.biorxiv.org/content/10.6... w/ Peter Visscher #genetics #statistics #genomics
biorxiv.org
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
Our adaptation of the Lee formula converts Nagelkerke's R² directly to the liability scale, using only population prevalence and sample case fraction. It works on already published estimates, with no individual-level data needed. R function included.
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
The liability-scale R² of Lee et al. (Genet Epidemiol, 2012) makes polygenic score performance comparable, but it takes linear-regression R² as input. Some studies plug in Nagelkerke's R² instead, which we show gives biased estimates.
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
New preprint 🧵 Nagelkerke's R² is widely used to report polygenic score performance for binary traits, but it depends on prevalence and case fraction, so you can't compare it across diseases or studies. We derive a simple conversion to the liability scale. 👇
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
4/* 📄 Preprint: www.biorxiv.org/content/10.6... w/ Peter Visscher #genetics #statistics #genomics
biorxiv.org
From Nagelkerke's R2 to Liability-Scale Variance Explained for Polygenic Scores
It is desirable to quantify the prediction accuracy of polygenic scores (PGS) for disease on the scale of liability and adjusted for case-control ascertainment in the test sample, because that allows ...
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
3/ Our adaptation of the Lee formula converts Nagelkerke's R² directly to the liability scale, using only population prevalence and sample case fraction. It works on already published estimates, with no individual-level data needed. R function included.
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Emil Uffelmann @euffelmann.bsky.social · 21/09/2026
2/ The liability-scale R² of Lee et al. (Genet Epidemiol, 2012) makes polygenic score performance comparable, but it takes linear-regression R² as input. Some studies plug in Nagelkerke's R² instead, which we show gives biased estimates.
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Jonathan Pritchard @jkpritch.bsky.social · 09/08/2026
Must-know numbers in human genetics -- As many of you know, I'm writing a free online textbook in human genetics. In this blog post I cover a key skill for genome scientists from that book: how to use mental math to figure out key genome properties. jkpritchard.substack.com/p/on-fermi-p...
jkpritchard.substack.com
On Fermi Problems in Human Genetics
and some very useful numbers about human genomes to get you started!
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PBF Comics @pbfcomics.bsky.social · 20/07/2026
“What a beautiful universe, hon" says a telescope as gazes upon an aurora borealis. “It really is”, responds the telescope's partner, who it turns out is not a telescope, but a microscope. Hands full of algae, she wades waist deep in a disgusting swamp, amazed by the heavenly microscopic life all around them.
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Reposted by Emil Uffelmann
Joni Coleman @jonicoleman.bsky.social · 24/06/2026
I'm at #BGA2026 #BGA26(?) this week. Out of practice with this skeeting thing, so we'll see how we go...! Introductory remarks from the local hosts here in sunny Amsterdam, to be followed by a plenary from the excellent Wouter Peyrot @behaviorgenetic.bsky.social
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FinnGen @finngen.bsky.social · 03/06/2026
We are pleased to announce the release of FinnGen DF13 results! 🧬 While the number of participants remains unchanged, DF13 incorporates updated health register data, increasing the number of cases across most disease endpoints. Browsing & download instructions here: www.finngen.fi/en/access_re...
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Chris Simms @chrisnsimms.bsky.social · 02/06/2026
It a HUGE study looking at the genetics of around 2.8 million people. The work is published as a preprint on medRxiv, so hasn't yet been peer reviewed. www.medrxiv.org/content/10.1...
medrxiv.org
Genomic analyses reveal new insights into Alzheimer’s disease
Alzheimer’s disease (AD) is the most common cause of dementia, with global case numbers projected to reach 153 million in 2050[1][1]. AD is highly heritable, with twin-based heritability estimates of ...
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Chris Simms @chrisnsimms.bsky.social · 02/06/2026
And here's another, this one for @newscientist.com, on the biggest genome-wide association study yet of Alzheimer’s. It has identified 48 new gene locations associated with the condition, which could help us find drug targets to prevent it. 🧪 #health #medicine www.newscientist.com/article/2528...
newscientist.com
Huge study of Alzheimer’s genetics identifies new drug targets
Almost 50 more genes have been flagged as being linked to Alzheimer’s, along with changes in activity in crucial cells that disappear as dementia progresses
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Emil Uffelmann @euffelmann.bsky.social · 26/05/2026
🧬 FUMA v2.0.0 is out, updated by Tanya Phung @ CTG Lab New FLAMES module (effector gene prioritization), new QTLs Analysis module, and expanded xQTL datasets in SNP2GENE fuma.ctglab.nl
fuma.ctglab.nl
Functional Mapping and Annotation of Genome-wide association studies
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Sacha Epskamp @sachaepskamp.bsky.social · 18/04/2026
Exam prep for a research and statistics exam in 2026! sachaepskamp.com/PL2132_games...
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Emil Uffelmann @euffelmann.bsky.social · 12/02/2026
To me, it reveals his humility. Not "I know," not "I discovered," but "I think." Shows he had doubts, like any of us.
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Uku Vainik @ukuvainik.bsky.social · 24/10/2025
I know that Galton called out for sharing data in 1901
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
🚨 The preprint for our GWAS of Alzheimer’s disease (AD) is out Preprint: medrxiv.org/content/10.1... 🧵
medrxiv.org
Genomic analyses reveal new insights into Alzheimer's disease
Alzheimer's disease (AD) is the most common cause of dementia, with global case numbers projected to reach 153 million in 2050. AD is highly heritable, with twin-based heritability estimates of 60-80%...
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Danielle @daniposthu.bsky.social · 14/10/2025
Proud that the third GWAS for Alzheimer's dementia from the PGC-ALZ working group was just posted online! Huge amounts of work, and what a great collaboration! Check out our exciting findings below 👇 @pgcgenetics.bsky.social #ctglab #alzheimer #dementia #GWAS
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
special thanks to Douglas Wightman (shared first author), my PIs @daniposthu.bsky.social & Ole Andreassen, and the whole Alzheimer's disease working group of the Psychiatric Genomics Consortium
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
This study was only possible thanks to a collaboration of >100 co-authors, biobanks, pharma partners, direct-to-consumer companies, and, most importantly, the nearly 3 million participants who shared their data. I am immensely grateful for their participation.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
The paper contains many more analyses and details. Check out the paper if interested. Preprint: www.medrxiv.org/content/10.1...
medrxiv.org
Genomic analyses reveal new insights into Alzheimer's disease
Alzheimer's disease (AD) is the most common cause of dementia, with global case numbers projected to reach 153 million in 2050. AD is highly heritable, with twin-based heritability estimates of 60-80%...
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
While ~90% of our data were from Europeans, our multi-ancestry design and ancestry-specific summary statistics pave the way for more diverse future AD GWASs.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
We also generated stratified GWAS results by sex, ancestry, and phenotype definition, and versions excluding the UK Biobank. All summary statistics will be made publicly available upon acceptance to maximize reuse and transparency.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Our polygenic prediction models explained up to 17% and, on average 13% of variance in European cohorts. Given that SNP-heritability estimates are the theoretical upper limit for polygenic prediction, the LDSC estimates are clearly underestimates.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Interestingly, using LAVA, we estimate that the SNP-heritability of the APOE region alone is ~9%.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Using SBayesRC, which models a mixture of SNP effect sizes and can better account for large-effect variants, we estimated SNP-heritability at ~19% (vs. 6% from LDSC). Estimates were similar across African and East Asian ancestries.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
AD GWASs have long been plagued by low SNP-heritabilities (~5%), far below the 60–80% twin-based estimates.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Sncg and Sst, two GABAergic neurons, have been previously shown to be vulnerable early on in the AD disease process, suggesting that AD-associated variants may influence gene expression in vulnerable neuronal subtypes, leading to neuronal cell death.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
We found enrichment for: Upregulated genes in microglia, and downregulated genes in three neuronal subtypes (Sncg, Sst, and L6 IT Car3).
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
We also went further: Using differential expression between AD cases and controls, we tested whether up- or down-regulated genes in specific cell types were enriched for genetic signal.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Previous AD GWASs using gene expression in healthy controls linked genetic risk mainly to microglia. We replicate that finding: genes highly expressed in microglia show strong association with AD risk.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
We identified 118 loci in a multi-ancestry GWAS and 9 more in a European-only GWAS (total = 127 loci). Of these, 48 were novel, including 8 potential drug targets: QPCT, EGFR, KEAP1, SYK, AXL, RRM2B, CACNA1S, and IL23A.
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
Summary: We analyzed ~180K cases & 2.6M controls, identified 127 loci (48 new), improved heritability estimates (19% in Europeans) & PGS prediction (mean 13%), found potential drug targets, and enrichment in microglia and three neuronal cell types. More details below ⬇️
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Emil Uffelmann @euffelmann.bsky.social · 14/10/2025
🚨 The preprint for our GWAS of Alzheimer’s disease (AD) is out Preprint: medrxiv.org/content/10.1... 🧵
medrxiv.org
Genomic analyses reveal new insights into Alzheimer's disease
Alzheimer's disease (AD) is the most common cause of dementia, with global case numbers projected to reach 153 million in 2050. AD is highly heritable, with twin-based heritability estimates of 60-80%...
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
A big thank you to Wouter Peyrot for his great supervision and teaching me a great deal about stats gen, and to my other co-authors @daniposthu.bsky.social, Alkes Price, as well as to all members of the schizophrenia and major depressive disorder working groups of the psychiatric genomics consortium
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
Code and a tutorial for the BPC approach can be found here: github.com/euffelmann/bpc
github.com
GitHub - euffelmann/bpc: Bayesian polygenic score Probability Conversion (BPC) approach
Bayesian polygenic score Probability Conversion (BPC) approach - GitHub - euffelmann/bpc: Bayesian polygenic score Probability Conversion (BPC) approach
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
A limiting factor for the usefulness of the BPC approach is the magnitude of R2. While most PGSs explain little variance, some are already proposed to have clinical utility; as GWAS sample sizes increase, their utility will also grow. See the paper for more limitations: rdcu.be/eIjvC
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
We show in simulations and empirical data that this simple way of estimating R2 works surprisingly well, outperforming another published approach.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
In a population reference sample (e.g., 1000 Genomes), where the sample disorder prevalence is the same as in the population, the variance of a PGS on the liability scale will be equal to its R2. That is, no phenotype data is required.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
Our approach depends on a valid estimate of R2. Because we wanted to avoid requiring a tuning dataset that will rarely be available in clinical settings, we developed a new way of estimating R2 using GWAS sumstats and public reference data only.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
We also compared the calibration of BPC to other methods using tuning samples (with geno- and phenotype data) and show that it performs similarly at smaller tuning sample sizes, but worse at larger tuning sample sizes. Because tuning samples are difficult to obtain, BPC may often be preferred.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
We note that the calibration of the Pain et al (2022) method can be improved with some simple tweaks, which we explore in the supplement. The BPC approach still achieves better calibration.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
It is also well calibrated in empirical analyses, where we analyzed 9 disorders of varying genetic architectures
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
We show in simulations, across different parameter settings, that the BPC approach is very well calibrated, outperforming a published method.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
To evaluate the BPC approach, we use a metric called the Integrated Calibration Index (ICI): the weighted average of the absolute difference between the real disorder probability and the predicted disorder probability, where 0 indicates perfect calibration.
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Emil Uffelmann @euffelmann.bsky.social · 27/09/2025
This is achieved by transforming a Bayesian PGS (computed using an existing method, e.g., PRS-CS or SBayesR) to its underlying liability scale, estimating the variances of the PGS in cases and controls based on theory, and applying Bayes’ Theorem to compute the probability.
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