Overview

Clinical Phenotype: Alzheimer's Disease
Reference Assembly: GRCh37/hg19
Position: Chr11:121454244 G>A
dbSNP ID: rs765993346
Coding/Non-Coding: Coding
DNA Change: Substitution
Expected Protein Consequence: Missense
Codon Change: GGG to AGG
Reference Isoform: SORL1 Isoform 1 (2214 aa)
Genomic Region: Exon 26

Findings

Among 927 late-onset Alzheimer’s disease cases, 852 early onset AD cases and 1,273 controls from the Alzheimer Disease Exome Sequencing France (ADESFR) project, one control subject was found to be a heterozygous carrier of this variant (Bellenguez et al., 2017).

In a study that included 15,808 Alzheimer’s cases and 16,097 control subjects from multiple European and American cohorts, including ADESFR, this allele was observed once among the controls (Holstege et al., 2022).

Functional Consequences

The SORL1 protein contains 11 complement-type repeats (CRs). A majority of known SORL1 ligands, including APP, bind to the CR cluster. Glycine-1220 is located at position 38 in CR4 and is one of a pair of glycines—located at positions 27 and 38—that is conserved in eight of the 11 CRs. Based on this degree of conservation, Andersen and colleagues predicted that substitutions of glycine at residue 1220 are moderately likely to increase AD risk (Andersen et al., 2023).

Substitutions of a conserved glycine at position 38 were found in 26 AD cases and 15 controls when the mega dataset cited above (Holstege et al., 2022) was expanded to 18,959 AD cases and 21,893 controls (Holstege et al., 2023). In aggregate, these variants associated with an increased risk of AD (odds ratio: 2.0; 95% confidence interval: 1.06 – 3.78; p = 0.040).

A pathogenic variant was identified in a homologous position in complement factor I (CFI), leading to CFI deficiency (Andersen et al., 2023).

This variant was predicted to be deleterious by SIFT, probably damaging by PolyPhen-2, and disease-causing by Mutation Taster (Bellenguez et al., 2017).

In a study investigating the effects of SORL1 missense mutations on protein processing, the G1220R variant did not affect the maturation (glycosylation) of SORL1 overexpressed in HEK293 cells (Rovelet-Lecrux et al., 2021).

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References

Paper Citations

1. Bellenguez C, Charbonnier C, Grenier-Boley B, Quenez O, Le Guennec K, Nicolas G, Chauhan G, Wallon D, Rousseau S, Richard AC, Boland A, Bourque G, Munter HM, Olaso R, Meyer V, Rollin-Sillaire A, Pasquier F, Letenneur L, Redon R, Dartigues JF, Tzourio C, Frebourg T, Lathrop M, Deleuze JF, Hannequin D, Genin E, Amouyel P, Debette S, Lambert JC, Campion D, CNR MAJ collaborators. Contribution to Alzheimer's disease risk of rare variants in TREM2, SORL1, and ABCA7 in 1779 cases and 1273 controls. Neurobiol Aging. 2017 Nov;59:220.e1-220.e9. Epub 2017 Jul 14 PubMed.
2. Holstege H, Hulsman M, Charbonnier C, Grenier-Boley B, Quenez O, Grozeva D, van Rooij JG, Sims R, Ahmad S, Amin N, Norsworthy PJ, Dols-Icardo O, Hummerich H, Kawalia A, Amouyel P, Beecham GW, Berr C, Bis JC, Boland A, Bossù P, Bouwman F, Bras J, Campion D, Cochran JN, Daniele A, Dartigues JF, Debette S, Deleuze JF, Denning N, DeStefano AL, Farrer LA, Fernández MV, Fox NC, Galimberti D, Genin E, Gille JJ, Le Guen Y, Guerreiro R, Haines JL, Holmes C, Ikram MA, Ikram MK, Jansen IE, Kraaij R, Lathrop M, Lemstra AW, Lleó A, Luckcuck L, Mannens MM, Marshall R, Martin ER, Masullo C, Mayeux R, Mecocci P, Meggy A, Mol MO, Morgan K, Myers RM, Nacmias B, Naj AC, Napolioni V, Pasquier F, Pastor P, Pericak-Vance MA, Raybould R, Redon R, Reinders MJ, Richard AC, Riedel-Heller SG, Rivadeneira F, Rousseau S, Ryan NS, Saad S, Sanchez-Juan P, Schellenberg GD, Scheltens P, Schott JM, Seripa D, Seshadri S, Sie D, Sistermans EA, Sorbi S, van Spaendonk R, Spalletta G, Tesi N, Tijms B, Uitterlinden AG, van der Lee SJ, Visser PJ, Wagner M, Wallon D, Wang LS, Zarea A, Clarimon J, van Swieten JC, Greicius MD, Yokoyama JS, Cruchaga C, Hardy J, Ramirez A, Mead S, van der Flier WM, van Duijn CM, Williams J, Nicolas G, Bellenguez C, Lambert JC. Exome sequencing identifies rare damaging variants in ATP8B4 and ABCA1 as risk factors for Alzheimer's disease. Nat Genet. 2022 Dec;54(12):1786-1794. Epub 2022 Nov 21 PubMed.
3. Andersen OM, Monti G, Jensen AM, deWaal M, Hulsman M, Olsen JG, Holstege H. Relying on the relationship with known disease-causing variants in homologous proteins to predict pathogenicity of SORL1 variants in Alzheimer's disease. 2023 Feb 27 10.1101/2023.02.27.524103 (version 1) bioRxiv.
4. Holstege H, deWaal MW, Tesi N, vanderLee SJ, ADESconsortium, ADSPconsortium, StEP-ADconsortium, Knight-ADRC, UCSF/NYGC/UAB, Vogel M, vanSpaendonk R, Hulsman M, Andersen OM. Effect of prioritized SORL1 missense variants supports clinical consideration for familial Alzheimer's Disease. 2023 Jul 16 10.1101/2023.07.13.23292622 (version 1) medRxiv.
5. Rovelet-Lecrux A, Feuillette S, Miguel L, Schramm C, Pernet S, Quenez O, Ségalas-Milazzo I, Guilhaudis L, Rousseau S, Riou G, Frébourg T, Campion D, Nicolas G, Lecourtois M. Impaired SorLA maturation and trafficking as a new mechanism for SORL1 missense variants in Alzheimer disease. Acta Neuropathol Commun. 2021 Dec 18;9(1):196. PubMed.

Further Reading

No Available Further Reading