chr3-179198865-C-T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP2

The NM_006218.4(PIK3CA):​c.40C>T​(p.His14Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000007 in 1,428,930 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. H14Q) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 7.0e-7 ( 0 hom. )

Consequence

PIK3CA
NM_006218.4 missense

Scores

5
10
4

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.30

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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
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.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
PIK3CANM_006218.4 linkc.40C>T p.His14Tyr missense_variant Exon 2 of 21 ENST00000263967.4 NP_006209.2 P42336Q4LE51
PIK3CAXM_006713658.5 linkc.40C>T p.His14Tyr missense_variant Exon 2 of 21 XP_006713721.1 P42336Q4LE51

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
PIK3CAENST00000263967.4 linkc.40C>T p.His14Tyr missense_variant Exon 2 of 21 2 NM_006218.4 ENSP00000263967.3 P42336

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
7.00e-7
AC:
1
AN:
1428930
Hom.:
0
Cov.:
29
AF XY:
0.00
AC XY:
0
AN XY:
709398
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
31792
American (AMR)
AF:
0.00
AC:
0
AN:
37044
Ashkenazi Jewish (ASJ)
AF:
0.0000411
AC:
1
AN:
24352
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39396
South Asian (SAS)
AF:
0.00
AC:
0
AN:
80510
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52594
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5602
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1098676
Other (OTH)
AF:
0.00
AC:
0
AN:
58964
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Cowden syndrome Uncertain:1
Nov 18, 2018
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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 histidine with tyrosine at codon 14 of the PIK3CA protein (p.His14Tyr). The histidine residue is highly conserved and there is a moderate physicochemical difference between histidine and tyrosine. 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.26
BayesDel_addAF
Pathogenic
0.18
D
BayesDel_noAF
Uncertain
0.020
CADD
Benign
23
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.48
.;T;.;.
Eigen
Uncertain
0.63
Eigen_PC
Uncertain
0.66
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Uncertain
0.92
D;D;D;T
M_CAP
Benign
0.048
D
MetaRNN
Uncertain
0.73
D;D;D;D
MetaSVM
Uncertain
-0.26
T
MutationAssessor
Benign
0.55
.;N;.;.
PhyloP100
7.3
PrimateAI
Pathogenic
0.90
D
PROVEAN
Pathogenic
-6.0
D;N;.;N
REVEL
Uncertain
0.60
Sift
Uncertain
0.023
.;D;.;T
Sift4G
Pathogenic
0.0
D;T;.;T
Polyphen
0.98
.;D;.;.
Vest4
0.48
MutPred
0.47
Loss of disorder (P = 0.0467);Loss of disorder (P = 0.0467);Loss of disorder (P = 0.0467);Loss of disorder (P = 0.0467);
MVP
0.74
MPC
1.9
ClinPred
0.99
D
GERP RS
5.1
Varity_R
0.49
gMVP
0.50
Mutation Taster
=19/81
disease causing

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

Other links and lift over

dbSNP: rs1576931874; hg19: chr3-178916653; API