rs200951754

Variant names:

• chr3-179210258-G-A
• rs200951754
• NM_006218.4:c.1324G>A

Your query was ambiguous. Multiple possible variants found:

• chr3-179210258-G-A
• chr3-179210258-G-C
• chr3-179210258-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_006218.4(PIK3CA):​c.1324G>A​(p.Ala442Thr) 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A442P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: PIK3CA NM_006218.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60
• Publications: 1 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 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, 8 uncertain in NM_006218.4
• 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
PIK3CA	NM_006218.4	c.1324G>A	p.Ala442Thr	missense_variant	Exon 8 of 21	ENST00000263967.4	NP_006209.2
PIK3CA	XM_006713658.5	c.1324G>A	p.Ala442Thr	missense_variant	Exon 8 of 21		XP_006713721.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIK3CA	ENST00000263967.4	c.1324G>A	p.Ala442Thr	missense_variant	Exon 8 of 21	2	NM_006218.4	ENSP00000263967.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1445282 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 718758

African (AFR) AF: 0.00 AC: 0 AN: 32246

American (AMR) AF: 0.00 AC: 0 AN: 39012

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25498

East Asian (EAS) AF: 0.00 AC: 0 AN: 39400

South Asian (SAS) AF: 0.00 AC: 0 AN: 82466

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53286

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5734

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1107876

Other (OTH) AF: 0.00 AC: 0 AN: 59764

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cowden syndrome Uncertain:1

Aug 03, 2020

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. 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, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with PIK3CA-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with threonine at codon 442 of the PIK3CA protein (p.Ala442Thr). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and threonine.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	23
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.46	T;.
Eigen	Benign	-0.095
Eigen_PC	Benign	0.19
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Benign	0.035	D
MetaRNN	Uncertain	0.51	D;D
MetaSVM	Benign	-0.78	T
MutationAssessor	Benign	0.075	N;.
PhyloP100		9.6
PrimateAI	Pathogenic	0.83	D
PROVEAN	Benign	0.81	N;.
REVEL	Uncertain	0.34
Sift	Benign	0.82	T;.
Sift4G	Benign	1.0	T;.
Vest4		0.80
ClinPred		0.67	D
GERP RS		5.6
Varity_R		0.32
gMVP		0.71
Mutation Taster		=17/83	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs200951754; hg19: chr3-178928046;