rs1553428545

Variant names:

• chr1-243664832-C-T
• rs1553428545
• NM_005465.7:c.224G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP3

The NM_005465.7(AKT3):​c.224G>A​(p.Arg75Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: AKT3 NM_005465.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.88
• Publications: 0 publications found

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 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-polymicrogyria-polydactyly-hydrocephalus syndrome 1

  Inheritance: AD Classification: STRONG Submitted by: G2P
• megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Illumina, Labcorp Genetics (formerly Invitae)
• megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• microcephaly

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 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, 3 uncertain in NM_005465.7
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the AKT3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 13 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 3.946 (above the threshold of 3.09). Trascript score misZ: 4.2291 (above the threshold of 3.09). GenCC associations: The gene is linked to megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2, microcephaly, megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1, megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome, overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.758

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AKT3	NM_005465.7	c.224G>A	p.Arg75Lys	missense_variant	Exon 4 of 14	ENST00000673466.1	NP_005456.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AKT3	ENST00000673466.1	c.224G>A	p.Arg75Lys	missense_variant	Exon 4 of 14		NM_005465.7	ENSP00000500582.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Jan 31, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 75 of the AKT3 protein (p.Arg75Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of AKT3-related conditions (internal data). ClinVar contains an entry for this variant (Variation ID: 475213). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests 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	Pathogenic	0.97
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	.;.;D;D;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Benign	0.0083	T
MetaRNN	Pathogenic	0.76	D;D;D;D;D
MetaSVM	Benign	-0.75	T
MutationAssessor	Uncertain	2.3	M;M;M;M;.
PhyloP100		7.9
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-2.8	D;D;D;D;D
REVEL	Uncertain	0.37
Sift	Benign	0.076	T;T;T;T;D
Sift4G	Benign	0.13	T;T;T;T;D
Polyphen		0.96	D;D;D;D;.
Vest4		0.67
MutPred		0.67		Gain of methylation at R75 (P = 3e-04);Gain of methylation at R75 (P = 3e-04);Gain of methylation at R75 (P = 3e-04);Gain of methylation at R75 (P = 3e-04);Gain of methylation at R75 (P = 3e-04);
MVP		0.74
MPC		1.3
ClinPred		0.99	D
GERP RS		6.1
Varity_R		0.89
gMVP		0.91
Mutation Taster		=17/83	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

Other links and lift over

dbSNP: rs1553428545; hg19: chr1-243828134;