rs397514606

Positions:

• chr1-243695714-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PS2_Moderate PM1_Supporting PS4 PS3_Supporting PP2 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.49G>A (NM_005465.7) variant in AKT3 is a missense variant predicted to cause substitution of (p.Glu17Lys). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). AKT3, in which the variant was identified, is defined by the ClinGen Brain Malformations Expert Panel as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). This variant resides within the pleckstrin homology domain of AKT3 that is defined as a critical functional domain by the ClinGen BMEP (PMID:28969385) (PM1_Supporting). This variant has been shown to significantly increase phosphorylation levels in experiments with case and control cells of similar isogenic backgrounds indicating that this variant impacts protein function (PMID:18813315) (PS3_Supporting). The prevalence of the variant in affected individuals is significantly increased compared with the prevalence in controls (PS4; PMIDs: 28969385, 22500628, 22729223; identified in 4 individuals with neuroimaging demonstrating at least one large cerebral hemisphere with cortical malformation(s) and 7 tumor samples in the literature and COSMIC). Testing of unaffected and affected tissue show variable allelic fractions consistent with a post-zygotic event (PS2_Moderate; PMID:22500628). In summary, this variant meets the criteria to be classified as Pathogenic for mosaic autosomal dominant overgrowth with or without cerebral malformations due to abnormalities in MTOR-pathway genes based on the ACMG/AMP criteria applied, as specified by the ClinGen Brain Malformations Expert Panel: PM2_P, PP2, PM1_P, PS3_P, PS4, PS2_M; 10 points (VCEP specifications version 1; Approved: 1/31/2021) LINK:https://erepo.genome.network/evrepo/ui/classification/CA130584/MONDO:0016054/018

• Frequency: Genomes: not found (cov: 32)
• Consequence: AKT3 NM_005465.7 missense, splice_region
• Clinical Significance: Pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: 7.90

Genes affected

AKT3 (HGNC:393): (AKT serine/threonine kinase 3) The protein encoded by this gene is a member of the AKT, also called PKB, serine/threonine protein kinase family. AKT kinases are known to be regulators of cell signaling in response to insulin and growth factors. They are involved in a wide variety of biological processes including cell proliferation, differentiation, apoptosis, tumorigenesis, as well as glycogen synthesis and glucose uptake. This kinase has been shown to be stimulated by platelet-derived growth factor (PDGF), insulin, and insulin-like growth factor 1 (IGF1). Alternatively splice transcript variants encoding distinct isoforms have been described. [provided by RefSeq, Jul 2008]

AKT3 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PS2: For more information check the summary or visit ClinGen Evidence Repository.
• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP2: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
AKT3	NM_005465.7	c.49G>A	p.Glu17Lys	missense_variant, splice_region_variant	3/14	ENST00000673466.1	NP_005456.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
AKT3	ENST00000673466.1	c.49G>A	p.Glu17Lys	missense_variant, splice_region_variant	3/14		NM_005465.7	ENSP00000500582.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

Overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen Brain Malformations Variant Curation Expert Panel

Feb 12, 2022

The c.49G>A (NM_005465.7) variant in AKT3 is a missense variant predicted to cause substitution of (p.Glu17Lys). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). AKT3, in which the variant was identified, is defined by the ClinGen Brain Malformations Expert Panel as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). This variant resides within the pleckstrin homology domain of AKT3 that is defined as a critical functional domain by the ClinGen BMEP (PMID: 28969385) (PM1_Supporting). This variant has been shown to significantly increase phosphorylation levels in experiments with case and control cells of similar isogenic backgrounds indicating that this variant impacts protein function (PMID: 18813315) (PS3_Supporting). The prevalence of the variant in affected individuals is significantly increased compared with the prevalence in controls (PS4; PMIDs: 28969385, 22500628, 22729223; identified in 4 individuals with neuroimaging demonstrating at least one large cerebral hemisphere with cortical malformation(s) and 7 tumor samples in the literature and COSMIC). Testing of unaffected and affected tissue show variable allelic fractions consistent with a post-zygotic event (PS2_Moderate; PMID: 22500628). In summary, this variant meets the criteria to be classified as Pathogenic for mosaic autosomal dominant overgrowth with or without cerebral malformations due to abnormalities in MTOR-pathway genes based on the ACMG/AMP criteria applied, as specified by the ClinGen Brain Malformations Expert Panel: PM2_P, PP2, PM1_P, PS3_P, PS4, PS2_M; 10 points (VCEP specifications version 1; Approved: 1/31/2021) -

Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jun 24, 2012

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Benign	0.0020	T
BayesDel_noAF	Benign	-0.23
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.93	.;.;D;D;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Benign	0.032	D
MetaRNN	Pathogenic	0.78	D;D;D;D;D
MetaSVM	Benign	-0.64	T
MutationAssessor	Uncertain	2.6	M;M;M;M;.
PrimateAI	Pathogenic	0.91	D
PROVEAN	Uncertain	-3.7	D;D;D;D;D
REVEL	Uncertain	0.37
Sift	Uncertain	0.0030	D;D;D;D;D
Sift4G	Benign	0.072	T;T;T;T;T
Polyphen		1.0	D;D;D;D;.
Vest4		0.87
MutPred		0.65		Gain of MoRF binding (P = 0.0165);Gain of MoRF binding (P = 0.0165);Gain of MoRF binding (P = 0.0165);Gain of MoRF binding (P = 0.0165);Gain of MoRF binding (P = 0.0165);
MVP		0.66
MPC		2.6
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.92
gMVP		0.82

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

LitVar

Other links and lift over

dbSNP: rs397514606; hg19: chr1-243859016; COSMIC: COSV55605820;