Mutations

PSEN1 Q222H

Overview

Pathogenicity: Alzheimer's Disease : Likely Pathogenic
ACMG/AMP Pathogenicity Criteria: PS3, PM1, PM2, PP2, PP3
Clinical Phenotype: Alzheimer's Disease
Position: (GRCh38/hg38):Chr14:73192761 G>C
Position: (GRCh37/hg19):Chr14:73659469 G>C
dbSNP ID: rs63751072
Coding/Non-Coding: Coding
DNA Change: Substitution
Expected RNA Consequence: Substitution
Expected Protein Consequence: Missense
Codon Change: CAG to CAC
Reference Isoform: PSEN1 Isoform 1 (467 aa)
Genomic Region: Exon 7

Findings

This mutation was found in an Australian woman diagnosed with dementia at 35 years of age (Miklossy et al., 2003). She subsequently developed seizures, aphasia, decreasing mobility, and swallowing difficulties. Three family members also developed dementia in their late 30s or early 40s. The proband’s daughter was found to carry the mutation, but was asymptomatic at age 30.

The variant was also described in a case of sporadic AD with spastic paraparesis in a French study (Lanoiselee et al., 2017). The mutation carrier had an age at onset of 46 years and disease duration of 4 years.

The mutation was absent from 100 unrelated Australian controls (Miklossy et al., 2003) and from the gnomAD variant database (gnomAD v2.1.1, July 2021).

Neuropathology

In the Australian carrier, neuropathology was consistent with AD (Miklossy et al., 2003). Aβ42 but not Aβ40, was detectable by immunoblot and ELISA in frontal cortex homogenates. In the French carrier, AD biomarkers in cerebrospinal fluid, including Aβ42, tau, and phospho-tau, were consistent with AD (Lanoiselee et al., 2017). Brain imaging in this patient revealed diffuse cortical atrophy with moderate leukopathy, diffuse microbleeds, and bilateral hypoperfusion predominant in the right frontal and temporal cortices (Lacour et al., 2019). 

Biological Effect

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 increased Aβ42/Aβ40 and decreased Aβ37/Aβ42, both indicators of reduced Aβ trimming activity (Liu et al., 2022; Apr 2022 news). In addition, the variant increased Aβ43 levels.

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 : Likely 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-S

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

PM1-P

Located in a mutational hot spot and/or critical and well-established functional domain (e.g. active site of an enzyme) without benign variation. Q222H: Variant located at edge of mutational hot spot.

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: 17 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?

Paper Citations

  1. Miklossy J, Taddei K, Suva D, Verdile G, Fonte J, Fisher C, Gnjec A, Ghika J, Suard F, Mehta PD, McLean CA, Masters CL, Brooks WS, Martins RN. Two novel presenilin-1 mutations (Y256S and Q222H) are associated with early-onset Alzheimer's disease. Neurobiol Aging. 2003 Sep;24(5):655-62. PubMed.
  2. 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.
  3. Lacour M, Quenez O, Rovelet-Lecrux A, Salomon B, Rousseau S, Richard AC, Quillard-Muraine M, Pasquier F, Rollin-Sillaire A, Martinaud O, Zarea A, 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, Godefroy O, Formaglio M, Croisile B, Auriacombe S, Magnin E, Sauvée M, Marelli C, Gabelle A, Pariente J, Paquet C, Boland A, Deleuze JF, Campion D, Hannequin D, Nicolas G, Wallon D, collaborators of the CNR-MAJ. Causative Mutations and Genetic Risk Factors in Sporadic Early Onset Alzheimer's Disease Before 51 Years. J Alzheimers Dis. 2019;71(1):227-243. 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. 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

Papers

  1. Butterfield DA, Gnjec A, Poon HF, Castegna A, Pierce WM, Klein JB, Martins RN. Redox proteomics identification of oxidatively modified brain proteins in inherited Alzheimer's disease: an initial assessment. J Alzheimers Dis. 2006 Dec;10(4):391-7. PubMed.

Protein Diagram

Primary Papers

  1. Miklossy J, Taddei K, Suva D, Verdile G, Fonte J, Fisher C, Gnjec A, Ghika J, Suard F, Mehta PD, McLean CA, Masters CL, Brooks WS, Martins RN. Two novel presenilin-1 mutations (Y256S and Q222H) are associated with early-onset Alzheimer's disease. Neurobiol Aging. 2003 Sep;24(5):655-62. PubMed.

Other mutations at this position

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Alzpedia

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