3-179219986-T-C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 3P and 6B. PM1PP2BP4_ModerateBS2

The NM_006218.4(PIK3CA):c.1949T>C(p.Val650Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000759 in 1,449,830 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 (★★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

PIK3CA
NM_006218.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.74

Publications

0 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 -3 ACMG points.

PM1

In a domain PIK helical (size 177) in uniprot entity PK3CA_HUMAN there are 18 pathogenic changes around while only 0 benign (100%) 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=0.16839632).

BS2

High AC in GnomAdExome4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PIK3CA	NM_006218.4 link	c.1949T>C	p.Val650Ala	missense_variant	Exon 13 of 21	ENST00000263967.4	NP_006209.2	P42336Q4LE51
PIK3CA	XM_006713658.5 link	c.1949T>C	p.Val650Ala	missense_variant	Exon 13 of 21		XP_006713721.1	P42336Q4LE51

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIK3CA	ENST00000263967.4 link	c.1949T>C	p.Val650Ala	missense_variant	Exon 13 of 21	2	NM_006218.4	ENSP00000263967.3		P42336

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000759

AC:

AN:

1449830

Hom.:

Cov.:

AF XY:

0.00000694

AC XY:

AN XY:

720714

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32786

American (AMR)

AF:

0.00

AC:

AN:

41640

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25822

East Asian (EAS)

AF:

0.00

AC:

AN:

39432

South Asian (SAS)

AF:

0.00

AC:

AN:

82812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53230

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5722

European-Non Finnish (NFE)

AF:

0.00000992

AC:

AN:

1108446

Other (OTH)

AF:

0.00

AC:

AN:

59940

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.443

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

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Jun 07, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.V650A variant (also known as c.1949T>C), located in coding exon 12 of the PIK3CA gene, results from a T to C substitution at nucleotide position 1949. The valine at codon 650 is replaced by alanine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Cowden syndrome

Uncertain:1

Sep 01, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine with alanine at codon 650 of the PIK3CA protein (p.Val650Ala). The valine residue is highly conserved and there is a small physicochemical difference between valine and alanine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with PIK3CA-related conditions. 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 tolerated. 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 v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.099

BayesDel_addAF

Benign

-0.087

BayesDel_noAF

Benign

-0.36

CADD

Benign

(source)

DANN

Benign

0.93

DEOGEN2

Uncertain

0.54

D;.

Eigen

Benign

-0.46

Eigen_PC

Benign

-0.16

FATHMM_MKL

Uncertain

0.90

LIST_S2

Benign

0.83

T;T

M_CAP

Benign

0.018

MetaRNN

Benign

0.17

T;T

MetaSVM

Benign

-0.98

MutationAssessor

Benign

-0.98

N;.

PhyloP100

3.7

PrimateAI

Pathogenic

0.86

PROVEAN

Benign

0.98

N;.

REVEL

Benign

0.095

Sift

Benign

0.79

T;.

Sift4G

Benign

1.0

T;.

Polyphen

0.0

B;.

Vest4

0.29

MutPred

0.70

Loss of stability (P = 0.0669);Loss of stability (P = 0.0669);

MVP

0.31

MPC

1.7

ClinPred

0.81

GERP RS

5.5

Varity_R

0.24

gMVP

0.31

Mutation Taster

=68/32

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over