rs63750643

Positions:

• chr21-25891793-T-C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000484.4(APP):​c.2140A>G​(p.Thr714Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T714I) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: APP NM_000484.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 7.62

Genes affected

APP (HGNC:620): (amyloid beta precursor protein) This gene encodes a cell surface receptor and transmembrane precursor protein that is cleaved by secretases to form a number of peptides. Some of these peptides are secreted and can bind to the acetyltransferase complex APBB1/TIP60 to promote transcriptional activation, while others form the protein basis of the amyloid plaques found in the brains of patients with Alzheimer disease. In addition, two of the peptides are antimicrobial peptides, having been shown to have bacteriocidal and antifungal activities. Mutations in this gene have been implicated in autosomal dominant Alzheimer disease and cerebroarterial amyloidosis (cerebral amyloid angiopathy). Multiple transcript variants encoding several different isoforms have been found for this gene. [provided by RefSeq, Aug 2014]

APP (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a region_of_interest Interaction with PSEN1 (size 27) in uniprot entity A4_HUMAN there are 16 pathogenic changes around while only 0 benign (100%) in NM_000484.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr21-25891792-G-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.863
• PP5: Variant 21-25891793-T-C is Pathogenic according to our data. Variant chr21-25891793-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 18102.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr21-25891793-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APP	NM_000484.4	c.2140A>G	p.Thr714Ala	missense_variant	17/18	ENST00000346798.8	NP_000475.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APP	ENST00000346798.8	c.2140A>G	p.Thr714Ala	missense_variant	17/18	1	NM_000484.4	ENSP00000284981.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Alzheimer disease type 1 Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	May 28, 2002	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 04, 2022	- -

Alzheimer disease Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 07, 2022

Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Thr714 amino acid residue in APP. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11063718, 16033913, 18234110). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 18102). This missense change has been observed in individuals with early-onset Alzheimer disease (PMID: 12034808, 14769392, 18187157; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 714 of the APP protein (p.Thr714Ala). -

not provided Other:1

not provided, no classification provided

literature only

VIB Department of Molecular Genetics, University of Antwerp

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.69	D;.;.;.;.;.;.;.
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.86	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Benign	1.7	L;.;.;.;.;.;.;.
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-2.9	D;D;D;D;.;D;D;D
REVEL	Pathogenic	0.82
Sift	Benign	0.065	T;D;D;T;.;T;T;T
Sift4G	Benign	0.23	T;T;T;T;T;T;T;T
Polyphen		1.0	D;D;D;D;.;.;D;.
Vest4		0.95
MutPred		0.60		Gain of helix (P = 0.0496);.;.;.;.;.;.;.;
MVP		0.99
MPC		1.2
ClinPred		0.96	D
GERP RS		5.7
Varity_R		0.64
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs63750643; hg19: chr21-27264105; COSMIC: COSV61005117;