Mutations

PSEN1 T274R

Overview

Pathogenicity: Alzheimer's Disease : Not Classified
Clinical Phenotype: Alzheimer's Disease
Reference Assembly: GRCh37/hg19
Position: Chr14:73664790 C>G
dbSNP ID: rs63750284
Coding/Non-Coding: Coding
Mutation Type: Point, Missense
Codon Change: ACA to AGA
Reference Isoform: PSEN1 Isoform 1 (467 aa)
Genomic Region: Exon 8

Findings

This mutation was found in a screen for variants in the open reading frame of the PSEN1 gene in participants from the United States, Germany, and Canada who had been referred for AD diagnostic testing (Rogaeva et al., 2001). The cohort included 372 patients with AD and 42 asymptomatic individuals with a strong family history of AD. Evidence for co-segregation of this mutation with disease is not available.

This variant was absent from the gnomAD variant database (gnomAD v2.1.1, July 2021).

Neuropathology
Unknown

Biological Effect
In an in vitro assay using purified proteins to test the ability of this mutant to cleave the APP-C99 substrate, production of both Aβ40 and Aβ42 was undetectable (Sun et al., 2017). T274 is within a region that undergoes a dramatic conformational change as a result of APP binding (Zhou et al., 2019; Jan 2019 news). The region moves towards the APP β-strand, forming a new α-helix (TM6a) that interacts with residues in PSEN1's second transmembrane domain.

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). These authors classified the variant as likely pathogenic using the ACMG-AMP guidelines (Richards et al., 2015).

Last Updated: 13 Sep 2021

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References

News Citations

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

Paper Citations

  1. . Screening for PS1 mutations in a referral-based series of AD cases: 21 novel mutations. Neurology. 2001 Aug 28;57(4):621-5. PubMed.
  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.
  5. . Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015 May;17(5):405-24. Epub 2015 Mar 5 PubMed.

External Citations

  1. gnomAD v2.1.1

Further Reading

No Available Further Reading

Protein Diagram

Primary Papers

  1. . Screening for PS1 mutations in a referral-based series of AD cases: 21 novel mutations. Neurology. 2001 Aug 28;57(4):621-5. PubMed.

Other mutations at this position

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