Overview

Clinical Phenotype: Alzheimer's Disease
Position: (GRCh38/hg38):Chr11:121591105 G>C
Position: (GRCh37/hg19):Chr11:121461814 G>C
dbSNP ID: NA
Coding/Non-Coding: Coding
DNA Change: Substitution
Expected Protein Consequence: Missense
Codon Change: GGG to CGG
Reference Isoform: SORL1 Isoform 1 (2214 aa)
Genomic Region: Exon 31

Findings

In a pan-European cohort of 1255 early onset Alzheimer’s cases and 1938 controls from the European Early Onset Dementia Consortium, one Italian control subject was found to be a heterozygous carrier of this variant (Verheijen et al., 2016).

No additional carriers were found among 5198 AD cases and 4491 controls from the Alzheimer’s Disease Sequencing Project from whom whole-exome sequencing data were available, 1779 AD cases and 1273 controls from the Alzheimer Disease Exome Sequencing France project, 332 cases and 676 controls of European ancestry from the United Kingdom and North America (Campion et al., 2019), or 640 cases and 1268 controls from a multi-center Dutch sample (Holstege et al., 2017).

The G1440R variant is classified as likely pathogenic by the criteria of Holstege et al. (Holstege et al., 2017).

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-1440 is located at position 38 in CR9 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 1440 are moderately likely to increase AD risk (Andersen et al., 2023).

Substitutions of a conserved glycine at position 38 were found in 26 cases and 15 controls in a dataset including 18,959 AD cases and 21,893 controls from multiple European and American cohorts (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 damaging by SIFT, disease-causing by Mutation Taster, and probably damaging by PolyPhen-2 (Verheijen et al., 2016).

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References

Paper Citations

1. Verheijen J, Van den Bossche T, van der Zee J, Engelborghs S, Sanchez-Valle R, Lladó A, Graff C, Thonberg H, Pastor P, Ortega-Cubero S, Pastor MA, Benussi L, Ghidoni R, Binetti G, Clarimon J, Lleó A, Fortea J, de Mendonça A, Martins M, Grau-Rivera O, Gelpi E, Bettens K, Mateiu L, Dillen L, Cras P, De Deyn PP, Van Broeckhoven C, Sleegers K. A comprehensive study of the genetic impact of rare variants in SORL1 in European early-onset Alzheimer's disease. Acta Neuropathol. 2016 Aug;132(2):213-24. Epub 2016 Mar 30 PubMed.
2. Campion D, Charbonnier C, Nicolas G. SORL1 genetic variants and Alzheimer disease risk: a literature review and meta-analysis of sequencing data. Acta Neuropathol. 2019 Aug;138(2):173-186. Epub 2019 Mar 25 PubMed.
3. Holstege H, van der Lee SJ, Hulsman M, Wong TH, van Rooij JG, Weiss M, Louwersheimer E, Wolters FJ, Amin N, Uitterlinden AG, Hofman A, Ikram MA, van Swieten JC, Meijers-Heijboer H, van der Flier WM, Reinders MJ, van Duijn CM, Scheltens P. Characterization of pathogenic SORL1 genetic variants for association with Alzheimer's disease: a clinical interpretation strategy. Eur J Hum Genet. 2017 Aug;25(8):973-981. Epub 2017 May 24 PubMed.
4. 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.
5. 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.

Further Reading

No Available Further Reading