Mutations

PSEN1 F237L

Overview

Pathogenicity: Alzheimer's Disease : Pathogenic
ACMG/AMP Pathogenicity Criteria: PS3, PM1, PM2, PP2, PP3
Clinical Phenotype: Alzheimer's Disease
Reference Assembly: GRCh37/hg19
Position: Chr14:73659512 T>C
dbSNP ID: rs63750858
Coding/Non-Coding: Coding
DNA Change: Substitution
Expected RNA Consequence: Substitution
Expected Protein Consequence: Missense
Codon Change: TTT to CTT
Reference Isoform: PSEN1 Isoform 1 (467 aa)
Genomic Region: Exon 7

Findings

The mutation was found in a study of British AD patients with a family history of AD with at least one affected first-degree relative, and an age of onset of less than 61 years (Janssen et al., 2003). The age of onset of the proband was 46 years. Three members of the individual’s family, spanning two generations, were diagnosed with AD, with a mean age of onset of 51 years. DNA was unavailable from the affected relatives, however, so co-segregation of the mutation and disease could not be demonstrated. The mutation was absent from 100 healthy, unrelated white control patients. A subsequent study reported myoclonus in a British carrier (Ryan et al., 2016). This individual may have been the same individual reported in the earlier study, or a family member.

The mutation was also identified  in a French study that screened 170 families with at least two first-degree relatives suffering from early onset AD spanning two generations (Lanoiselée et al., 2017). Ages at onset in the family carrying the F237L variant were between 47 and 48, and their disease duration was between 2 and 4 years. The proband was homozygous for the APOE 3 allele. 

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

Neuropathology
Although neuropathological data are unavailable, one carrier had AD biomarker levels (Aβ42, tau, and phospho-tau) in cerebrospinal fluid that were consistent with AD (Lanoiselée et al., 2017).

Biological Effects

A study that examined a range of Aβ peptides produced by human embryonic kidney cells expressing this mutant and lacking endogenous PSEN1 and PSEN2 revealed decreased Aβ37/Aβ42, an indicator of reduced Aβ trimming activity, but the Aβ42/Aβ40 was similar to controls (Liu et al., 2022; Apr 2022 news). In this study, Aβ37/Aβ42 outperformed Aβ42/Aβ40 as a biomarker for distinguishing between control and AD samples. Also of note, levels of Aβ43, Aβ42, and Aβ40 were reduced compared with controls.

Codon 237 is evolutionarily conserved across human PSEN1, mouse PSEN1, and Caenorhabditis elegans Sel-12 protein, as well as between human PSEN1 and PSEN2 (Sodeyama et al., 2001). Moreover, a cryo-electron microscopy study of the atomic structure of γ-secretase bound to an APP fragment indicates that, in wild-type PSEN1, the phenylalanine at this position helps form a hydrophobic pocket in 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 : Pathogenic

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

PS3-M

Well-established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product. F237L: Decreased Aβ37/Aβ42 ratio; Aβ42/Aβ40 ratio similar to wildtype. Decreased levels of Aβ43, Aβ42, Aβ40.

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. F237L: 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.

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: 21 Nov 2022

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References

News Citations

  1. Ratio of Short to Long Aβ Peptides: Better Handle on Alzheimer's than Aβ42/40?
  2. CryoEM γ-Secretase Structures Nail APP, Notch Binding

Paper Citations

  1. Janssen JC, Beck JA, Campbell TA, Dickinson A, Fox NC, Harvey RJ, Houlden H, Rossor MN, Collinge J. Early onset familial Alzheimer's disease: Mutation frequency in 31 families. Neurology. 2003 Jan 28;60(2):235-9. PubMed.
  2. Ryan NS, Nicholas JM, Weston PS, Liang Y, Lashley T, Guerreiro R, Adamson G, Kenny J, Beck J, Chavez-Gutierrez L, de Strooper B, Revesz T, Holton J, Mead S, Rossor MN, Fox NC. Clinical phenotype and genetic associations in autosomal dominant familial Alzheimer's disease: a case series. Lancet Neurol. 2016 Dec;15(13):1326-1335. Epub 2016 Oct 21 PubMed.
  3. Lanoiselée HM, Nicolas G, Wallon D, Rovelet-Lecrux A, Lacour M, Rousseau S, Richard AC, Pasquier F, Rollin-Sillaire A, Martinaud O, Quillard-Muraine M, de la Sayette V, Boutoleau-Bretonniere C, Etcharry-Bouyx F, Chauviré V, Sarazin M, le Ber I, Epelbaum S, Jonveaux T, Rouaud O, Ceccaldi M, Félician O, Godefroy O, Formaglio M, Croisile B, Auriacombe S, Chamard L, Vincent JL, Sauvée M, Marelli-Tosi C, Gabelle A, Ozsancak C, Pariente J, Paquet C, Hannequin D, Campion D, collaborators of the CNR-MAJ project. APP, PSEN1, and PSEN2 mutations in early-onset Alzheimer disease: A genetic screening study of familial and sporadic cases. PLoS Med. 2017 Mar;14(3):e1002270. Epub 2017 Mar 28 PubMed.
  4. Liu L, Lauro BM, He A, Lee H, Bhattarai S, Wolfe MS, Bennett DA, Karch CM, Young-Pearse T, Dominantly Inherited Alzheimer Network (DIAN), Selkoe DJ. Identification of the Aβ37/42 peptide ratio in CSF as an improved Aβ biomarker for Alzheimer's disease. Alzheimers Dement. 2022 Mar 12; PubMed.
  5. Sodeyama N, Iwata T, Ishikawa K, Mizusawa H, Yamada M, Itoh Y, Otomo E, Matsushita M, Komatsuzaki Y. Very early onset Alzheimer's disease with spastic paraparesis associated with a novel presenilin 1 mutation (Phe237Ile). J Neurol Neurosurg Psychiatry. 2001 Oct;71(4):556-7. PubMed.
  6. Zhou R, Yang G, Guo X, Zhou Q, Lei J, Shi Y. Recognition of the amyloid precursor protein by human γ-secretase. Science. 2019 Feb 15;363(6428) Epub 2019 Jan 10 PubMed.
  7. Xiao X, Liu H, Liu X, Zhang W, Zhang S, Jiao B. 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

No Available Further Reading

Protein Diagram

Primary Papers

  1. Janssen JC, Beck JA, Campbell TA, Dickinson A, Fox NC, Harvey RJ, Houlden H, Rossor MN, Collinge J. Early onset familial Alzheimer's disease: Mutation frequency in 31 families. Neurology. 2003 Jan 28;60(2):235-9. PubMed.

Other mutations at this position

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Alzpedia

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