rs121913283

Positions:

• chr3-179234286-G-A
• chr3-179234286-G-C
• chr3-179234286-G-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PS1 PM1 PM2 PP2 PP5_Very_Strong

The NM_006218.4(PIK3CA):​c.3129G>A​(p.Met1043Ile) 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 Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in Lovd.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PIK3CA NM_006218.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 9.49

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 Pathogenic. Variant got 17 ACMG points.

• PS1: Transcript NM_006218.4 (PIK3CA) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in Lovd
• PM1: In a domain PI3K/PI4K catalytic (size 286) in uniprot entity PK3CA_HUMAN there are 8 pathogenic changes around while only 0 benign (100%) 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). The gene has 98 curated pathogenic missense variants (we use a threshold of 10). The gene has 13 curated benign missense variants. GenCC has associacion of the 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.
• PP5: Variant 3-179234286-G-A is Pathogenic according to our data. Variant chr3-179234286-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 179173.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PIK3CA	NM_006218.4	c.3129G>A	p.Met1043Ile	missense_variant	21/21	ENST00000263967.4	NP_006209.2
PIK3CA	XM_006713658.5	c.3129G>A	p.Met1043Ile	missense_variant	21/21		XP_006713721.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PIK3CA	ENST00000263967.4	c.3129G>A	p.Met1043Ile	missense_variant	21/21	2	NM_006218.4	ENSP00000263967.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

PIK3CA related overgrowth syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Clinical Genomics Laboratory, Washington University in St. Louis

Jan 20, 2015

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not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Oct 20, 2022

Identified in patients with features of PIK3CA-related overgrowth and brain malformations spectrum disorder referred for genetic testing at GeneDx and in the published literature (Kuentz et al., 2017); In silico analysis supports that this missense variant does not alter protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 33745098, 31831300, 22120714, 15930273, 26627007, 28151489) -

Non-small cell lung carcinoma Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jul 19, 2013

The Met1043Ile variant has been identified as a somatic change in tumors from mulitple tissues, including endometrium, lung, cervix, urinary tract and large intestine (COSMIC). -

Cowden syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 05, 2022

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects PIK3CA function (PMID: 15930273, 17376864, 22120714). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PIK3CA protein function. ClinVar contains an entry for this variant (Variation ID: 179173). This missense change has been observed in individual(s) with hemimegalencephaly (PMID: 28151489). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 1043 of the PIK3CA protein (p.Met1043Ile). -

Megalencephaly-capillary malformation-polymicrogyria syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Equipe Genetique des Anomalies du Developpement, Université de Bourgogne

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.34	T
Eigen	Benign	-0.20
Eigen_PC	Benign	0.13
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Benign	0.043	D
MetaRNN	Uncertain	0.64	D
MetaSVM	Benign	-0.76	T
MutationAssessor	Benign	-1.3	N
PrimateAI	Pathogenic	0.90	D
PROVEAN	Benign	-0.50	N
REVEL	Uncertain	0.37
Sift	Uncertain	0.016	D
Sift4G	Benign	0.11	T
Polyphen		0.14	B
Vest4		0.84
MutPred		0.54		Loss of ubiquitination at K1041 (P = 0.0502);
MVP		0.98
MPC		1.6
ClinPred		0.92	D
GERP RS		6.1
Varity_R		0.60
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: rs121913283; hg19: chr3-178952074; COSMIC: COSV55873376; COSMIC: COSV55873376;