Mutations

PSEN1 W165G

Overview

Pathogenicity: Alzheimer's Disease : Not Classified
ACMG/AMP Pathogenicity Criteria: PS3, PM1, PM2, PM5, PP2, PP3
Clinical Phenotype: Alzheimer's Disease
Reference Assembly: GRCh37/hg19
Position: Chr14:73653573 T>G
dbSNP ID: rs63751010
Coding/Non-Coding: Coding
Mutation Type: Point, Missense
Codon Change: TGG to GGG
Reference Isoform: PSEN1 Isoform 1 (467 aa)
Genomic Region: Exon 6

Findings

This mutation was identified in a Japanese woman who developed memory impairment at age 38 and experienced rapid subsequent cognitive decline (Higuchi et al., 2000). The family had at least five members affected by AD with mean ages of onset of 36 years, but co-segregation of the mutation with disease was not confirmed. The mutation was absent from 207 unrelated AD patients and 200 controls. It was also absent from the gnomAD variant database (gnomAD v2.1.1, June 2021).

Neuropathology

Neuropathological data are not available. However, two years after onset, the proband had slight, bilateral hypoperfusion of the parieto-occipital region and thalamus, as assessed by SPECT, as well as EEG alterations. No abnormalities were detected by MRI. Three years after onset, tau levels in the CSF were highly elevated.

Biological Effect

In experiments with isolated proteins, the mutation robustly increased the production of Aβ42, while reducing that of Aβ40, resulting in an increase in the Aβ42/Aβ40 ratio (Sun et al., 2017). A cryo-electron microscopy study of the atomic structure of γ-secretase bound to an APP fragment indicates that, in wild-type PSEN1, this residue is apposed to the APP transmembrane helix, with its side-chain reaching towards the interior of the substrate-binding pore (Zhou et al., 2019; Jan 2019 news).

Several in silico algorithms (SIFT, Polyphen-2, LRT, MutationTaster, MutationAssessor, FATHMM, PROVEAN, CADD, REVEL, and Reve in the VarCards database) predicted this variant is damaging (Xiao et al., 2021).

Pathogenicity

Alzheimer's Disease : Not Classified*

*This variant fulfilled some ACMG-AMP criteria, but it was not classified by Alzforum, because data for either a pathogenic or benign classification are lacking: only one affected carrier has been reported without co-segregation data, and the variant is absent—or very rare—in the gnomAD database.

This variant fulfilled the following criteria based on the ACMG/AMP guidelines. See a full list of the criteria in the Methods page.

PS3-S

Well-established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product.

PM1-S

Located in a mutational hot spot and/or critical and well-established functional domain (e.g. active site of an enzyme) without benign variation. W165G: Variant is in a mutational hot spot and Variant is in a mutational hot spot and cryo-EM data suggest residue is of functional importance.

PM2-M

Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium. *Alzforum uses the gnomAD variant database.

PM5-M

Novel missense change at an amino acid residue where a different missense change determined to be pathogenic has been seen before.

PP2-P

Missense variant in a gene that has a low rate of benign missense variation and where missense variants are a common mechanism of disease.

PP3-P

Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.). *In most cases, Alzforum applies this criterion when the variant’s PHRED-scaled CADD score is greater than or equal to 20.

Pathogenic (PS, PM, PP) Benign (BA, BS, BP)
Criteria Weighting Strong (-S) Moderate (-M) Supporting (-P) Supporting (-P) Strong (-S) Strongest (BA)

Last Updated: 22 Feb 2022

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References

News Citations

  1. CryoEM γ-Secretase Structures Nail APP, Notch Binding

Paper Citations

  1. . A novel PS1 Mutation (W165G) in a Japanese family with early-onset Alzheimer's disease. Alzheimer's Rep. 2000;3:227-31.
  2. . Analysis of 138 pathogenic mutations in presenilin-1 on the in vitro production of Aβ42 and Aβ40 peptides by γ-secretase. Proc Natl Acad Sci U S A. 2017 Jan 24;114(4):E476-E485. Epub 2016 Dec 5 PubMed.
  3. . Recognition of the amyloid precursor protein by human γ-secretase. Science. 2019 Feb 15;363(6428) Epub 2019 Jan 10 PubMed.
  4. . APP, PSEN1, and PSEN2 Variants in Alzheimer's Disease: Systematic Re-evaluation According to ACMG Guidelines. Front Aging Neurosci. 2021;13:695808. Epub 2021 Jun 18 PubMed.

External Citations

  1. gnomAD v2.1.1

Further Reading

Papers

  1. . Quantifying correlations between mutational sites in the catalytic subunit of γ-secretase. J Mol Graph Model. 2019 May;88:221-227. Epub 2019 Feb 8 PubMed.

Protein Diagram

Primary Papers

  1. . A novel PS1 Mutation (W165G) in a Japanese family with early-onset Alzheimer's disease. Alzheimer's Rep. 2000;3:227-31.

Other mutations at this position

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