3-179199698-A-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 3P and 5B. PM1PP2BP4BS2

The NM_006218.4(PIK3CA):c.361A>G(p.Ile121Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000156 in 1,605,458 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 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. I121L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

PIK3CA
NM_006218.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 8.94

Publications

1 publications found

Variant links:

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]

PIK3CA Gene-Disease associations (from GenCC):

overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
megalencephaly-capillary malformation-polymicrogyria syndrome
Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
vascular malformation
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
Cowden disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Cowden syndrome 5
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
familial ovarian cancer
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
hereditary breast carcinoma
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

PIK3CA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_006218.4

PP2

Missense variant in the PIK3CA gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 98 curated pathogenic missense variants (we use a threshold of 10). The gene has 13 curated benign missense variants. Gene score misZ: 5.5986 (above the threshold of 3.09). Trascript score misZ: 6.1406 (above the threshold of 3.09). GenCC associations: The gene is linked to megalencephaly-capillary malformation-polymicrogyria syndrome, vascular malformation, Cowden syndrome 5, overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes, Cowden disease, hereditary breast carcinoma, familial ovarian cancer.

BP4

Computational evidence support a benign effect (MetaRNN=0.32660884).

BS2

High AC in GnomAd4 at 5 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006218.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PIK3CA	NM_006218.4	MANE Select	c.361A>G	p.Ile121Val	missense	Exon 3 of 21	NP_006209.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
PIK3CA	ENST00000263967.4	TSL:2 MANE Select	c.361A>G	p.Ile121Val	missense	Exon 3 of 21	ENSP00000263967.3
PIK3CA	ENST00000643187.1		c.361A>G	p.Ile121Val	missense	Exon 3 of 22	ENSP00000493507.1
PIK3CA	ENST00000675467.1		n.3168A>G		non_coding_transcript_exon	Exon 2 of 20

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000160

AC:

AN:

249232

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000354

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000138

AC:

AN:

1453318

Hom.:

Cov.:

AF XY:

0.0000152

AC XY:

AN XY:

723444

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33286

American (AMR)

AF:

0.00

AC:

AN:

44688

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26056

East Asian (EAS)

AF:

0.00

AC:

AN:

39556

South Asian (SAS)

AF:

0.00

AC:

AN:

85976

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53342

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5750

European-Non Finnish (NFE)

AF:

0.0000163

AC:

AN:

1104564

Other (OTH)

AF:

0.0000333

AC:

AN:

60100

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.405

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74318

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41454

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

67998

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000901

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000123

AC:

ExAC

AF:

0.0000248

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cowden syndrome

Uncertain:1

Apr 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 121 of the PIK3CA protein (p.Ile121Val). This variant is present in population databases (rs371727887, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with PIK3CA-related conditions. ClinVar contains an entry for this variant (Variation ID: 246688). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on PIK3CA protein function. 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.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.084

BayesDel_addAF

Benign

-0.088

BayesDel_noAF

Benign

-0.23

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Uncertain

0.42

Eigen

Benign

0.12

Eigen_PC

Uncertain

0.24

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.91

M_CAP

Benign

0.011

MetaRNN

Benign

0.33

MetaSVM

Benign

-0.97

MutationAssessor

Benign

2.0

PhyloP100

8.9

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-0.88

REVEL

Benign

0.26

Sift

Benign

0.055

Sift4G

Benign

0.11

Polyphen

0.23

Vest4

0.63

MVP

0.45

MPC

0.71

ClinPred

0.24

GERP RS

5.8

Varity_R

0.25

gMVP

0.59

Mutation Taster

=54/46

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over