rs587777795

Variant names:

• chr3-179218328-GT-C
• rs587777795
• NM_006218.4:c.1658_1659delGTinsC

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP2

The NM_006218.4(PIK3CA):​c.1658_1659delGTinsC​(p.Ser553ThrfsTer7) variant causes a frameshift, 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 no classification for the single variant (no stars). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PIK3CA NM_006218.4 frameshift, missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.60
• Publications: 2 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: Pathogenic. The variant received 11 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• 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.1658_1659delGTinsC	p.Ser553ThrfsTer7	frameshift_variant, missense_variant	Exon 10 of 21	ENST00000263967.4	NP_006209.2
PIK3CA	XM_006713658.5	c.1658_1659delGTinsC	p.Ser553ThrfsTer7	frameshift_variant, missense_variant	Exon 10 of 21		XP_006713721.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PIK3CA	ENST00000263967.4	c.1658_1659delGTinsC	p.Ser553ThrfsTer7	frameshift_variant, missense_variant	Exon 10 of 21	2	NM_006218.4	ENSP00000263967.3

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.6
Mutation Taster		=1/199	disease causing (fs/PTC)

Splicing

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

Other links and lift over

dbSNP: rs587777795; hg19: chr3-178936116; COSMIC: COSV106083306;