Overview

Pathogenicity: Alzheimer's Disease : Pathogenic
Clinical Phenotype: Alzheimer's Disease
Reference Assembly: GRCh37 (105)
Position: Chr14:73653600 CTG>---
dbSNP ID: NA
Coding/Non-Coding: Coding
Mutation Type: Deletion
Codon Change: CTG to ---
Reference Isoform: PSEN1 isoform 1 (467 aa)
Genomic Region: Exon 6

Findings

The index patient, a 50-year-old male, suffered from progressive memory loss and depression (Tiedt et al., 2013). At age 53, he was diagnosed with early AD based on neuropsychological tests, neuroimaging, and analysis of cerebrospinal fluid (CSF) markers. The patient’s father and paternal grandmother also experienced memory loss and cognitive decline.

Neuropathology
Although neuropathology data are unavailable for this mutation, an MRI brain scan of the proband revealed slight temporal lobe atrophy.

Biological Effect
Measurements of AD biomarkers in the cerebrospinal fluid of the proband revealed increased levels of Aβ40, and reduced levels of Aβ42, resulting in a decreased Aβ42/Aβ40 ratio. A cryo-electron microscopy study of the atomic structure of γ-secretase bound to an APP fragment suggests mutations in L174 could alter the protein's local conformation and affect the positioning of residues that directly contribute to substrate binding (Zhou et al., 2019; Jan 2019 news).

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References

News Citations

1. CryoEM γ-Secretase Structures Nail APP, Notch Binding 11 Jan 2019

Paper Citations

1. Tiedt HO, Lueschow A, Winter P, Müller U. Previously not recognized deletion in presenilin-1 (p.Leu174del.) in a patient with early-onset familial Alzheimer's disease. Neurosci Lett. 2013 Jun 7;544:115-8. PubMed.
2. 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.

Further Reading

No Available Further Reading