3-179230065-A-G

Position:

• chr3-179230065-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_006218.4(PIK3CA):​c.2728A>G​(p.Ile910Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PIK3CA NM_006218.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.85

Genes affected

PIK3CA (HGNC:8975): (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) Phosphatidylinositol 3-kinase is composed of an 85 kDa regulatory subunit and a 110 kDa catalytic subunit. The protein encoded by this gene represents the catalytic subunit, which uses ATP to phosphorylate PtdIns, PtdIns4P and PtdIns(4,5)P2. This gene has been found to be oncogenic and has been implicated in cervical cancers. A pseudogene of this gene has been defined on chromosome 22. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_006218.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), PIK3CA. . Gene score misZ 5.5986 (greater than the threshold 3.09). Trascript score misZ 6.1406 (greater than threshold 3.09). GenCC has associacion of gene with hereditary breast carcinoma, vascular malformation, Cowden disease, Cowden syndrome 5, CLOVES syndrome, familial ovarian cancer, megalencephaly-capillary malformation-polymicrogyria syndrome, overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIK3CA	NM_006218.4	c.2728A>G	p.Ile910Val	missense_variant	19/21	ENST00000263967.4
PIK3CA	XM_006713658.5	c.2728A>G	p.Ile910Val	missense_variant	19/21

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIK3CA	ENST00000263967.4	c.2728A>G	p.Ile910Val	missense_variant	19/21	2	NM_006218.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cowden syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 25, 2018

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. This sequence change replaces isoleucine with valine at codon 910 of the PIK3CA protein (p.Ile910Val). The isoleucine residue is highly conserved and there is a small physicochemical difference between isoleucine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with PIK3CA-related disease. ClinVar contains an entry for this variant (Variation ID: 456542). Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Uncertain	0.066	T
BayesDel_noAF	Benign	-0.14
CADD	Benign	20
DANN	Benign	0.79
DEOGEN2	Benign	0.31	T;.
Eigen	Benign	0.037
Eigen_PC	Benign	0.17
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.85	T;D
M_CAP	Benign	0.020	T
MetaRNN	Uncertain	0.59	D;D
MetaSVM	Benign	-0.71	T
MutationAssessor	Benign	0.38	N;.
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Benign	0.41	N;.
REVEL	Uncertain	0.41
Sift	Benign	1.0	T;.
Sift4G	Benign	1.0	T;.
Polyphen		0.65	P;.
Vest4		0.59
MutPred		0.51		Gain of catalytic residue at I910 (P = 0.0739);Gain of catalytic residue at I910 (P = 0.0739);
MVP		0.71
MPC		1.4
ClinPred		0.83	D
GERP RS		4.5
Varity_R		0.077
gMVP		0.86

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1553825421; hg19: chr3-178947853;