1-160343422-G-C

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_015331.3(NCSTN):c.26G>C(p.Gly9Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G9E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: NCSTN NM_015331.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.195

Genes affected

NCSTN (HGNC:17091): (nicastrin) This gene encodes a type I transmembrane glycoprotein that is an integral component of the multimeric gamma-secretase complex. The encoded protein cleaves integral membrane proteins, including Notch receptors and beta-amyloid precursor protein, and may be a stabilizing cofactor required for gamma-secretase complex assembly. The cleavage of beta-amyloid precursor protein yields amyloid beta peptide, the main component of the neuritic plaque and the hallmark lesion in the brains of patients with Alzheimer's disease; however, the nature of the encoded protein's role in Alzheimer's disease is not known for certain. Mutations in this gene are associated with familial acne inversa. A pseudogene of this gene is present on chromosome 21. Alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined. [provided by RefSeq, Feb 2014]

COPA (HGNC:2230): (COPI coat complex subunit alpha) In eukaryotic cells, protein transport between the endoplasmic reticulum and Golgi compartments is mediated in part by non-clathrin-coated vesicular coat proteins (COPs). Seven coat proteins have been identified, and they represent subunits of a complex known as coatomer. The subunits are designated alpha-COP, beta-COP, beta-prime-COP, gamma-COP, delta-COP, epsilon-COP, and zeta-COP. The alpha-COP, encoded by COPA, shares high sequence similarity with RET1P, the alpha subunit of the coatomer complex in yeast. Also, the N-terminal 25 amino acids of alpha-COP encode the bioactive peptide, xenin, which stimulates exocrine pancreatic secretion and may act as a gastrointestinal hormone. Alternative splicing results in multiple splice forms encoding distinct isoforms. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.051678628).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NCSTN	NM_015331.3	c.26G>C	p.Gly9Ala	missense_variant	1/17	ENST00000294785.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NCSTN	ENST00000294785.10	c.26G>C	p.Gly9Ala	missense_variant	1/17	1	NM_015331.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 29, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The alanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. This variant has not been reported in the literature in individuals affected with NCSTN-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 9 of the NCSTN protein (p.Gly9Ala). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.065
BayesDel_addAF	Benign	-0.031	T
BayesDel_noAF	Benign	-0.28
Cadd	Benign	1.3
Dann	Benign	0.81
DEOGEN2	Benign	0.18	T;T;T;T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.023	N
LIST_S2	Benign	0.62	T;T;T;T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.052	T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.7	L;.;.;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.43	T
PROVEAN	Benign	0.17	N;N;N;N
REVEL	Benign	0.21
Sift	Benign	1.0	T;T;T;T
Sift4G	Benign	1.0	T;T;T;T
Polyphen		0.0	B;.;.;.
Vest4		0.16
MutPred		0.23		Loss of relative solvent accessibility (P = 0.0071);Loss of relative solvent accessibility (P = 0.0071);Loss of relative solvent accessibility (P = 0.0071);Loss of relative solvent accessibility (P = 0.0071);
MVP		0.89
MPC		0.067
ClinPred		0.057	T
GERP RS		-1.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.041
gMVP		0.65

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: rs1041921165; hg19: chr1-160313212;