2-73902421-G-A

Position:

• chr2-73902421-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_001615.4(ACTG2):​c.188G>A​(p.Arg63Gln) 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 Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R63G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: ACTG2 NM_001615.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 9.94

Genes affected

ACTG2 (HGNC:145): (actin gamma 2, smooth muscle) Actins are highly conserved proteins that are involved in various types of cell motility and in the maintenance of the cytoskeleton. Three types of actins, alpha, beta and gamma, have been identified in vertebrates. Alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton and as mediators of internal cell motility. This gene encodes actin gamma 2; a smooth muscle actin found in enteric tissues. Alternative splicing results in multiple transcript variants encoding distinct isoforms. Based on similarity to peptide cleavage of related actins, the mature protein of this gene is formed by removal of two N-terminal peptides.[provided by RefSeq, Dec 2010]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-73902420-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 218310.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), ACTG2. . Gene score misZ 3.3487 (greater than the threshold 3.09). Trascript score misZ 4.3482 (greater than threshold 3.09). GenCC has associacion of gene with visceral myopathy 1, familial visceral myopathy, megacystis-microcolon-intestinal hypoperistalsis syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.912
• PP5: Variant 2-73902421-G-A is Pathogenic according to our data. Variant chr2-73902421-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 694269.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr2-73902421-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACTG2	NM_001615.4	c.188G>A	p.Arg63Gln	missense_variant	3/9	ENST00000345517.8
ACTG2	NM_001199893.2	c.126+984G>A		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACTG2	ENST00000345517.8	c.188G>A	p.Arg63Gln	missense_variant	3/9	1	NM_001615.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 55

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Megacystis-microcolon-intestinal hypoperistalsis syndrome 5 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jul 15, 2021

- -

Visceral myopathy 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

case-control

Wangler Lab, Baylor College of Medicine

Sep 30, 2019

The p.R63Q was seen in 3 individuals with visceral myopathy in the BCM MMIHS cohort as of September 2019. One was de novo, one family was maternally inherited and the mother exhibited uterine atony, and the other variant's inheritance could not be determined. The p.R63G variant in ACTG2 is also pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	D;D;.;D
Eigen	Uncertain	0.67
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.81	.;T;T;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.91	D;D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	3.3	M;.;.;M
MutationTaster	Benign	0.98	D;D;D;D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Benign	-2.1	N;D;D;N
REVEL	Pathogenic	0.82
Sift4G	Uncertain	0.014	D;D;D;D
Polyphen		0.99	D;D;.;D
Vest4		0.90
MutPred		0.82		Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);
MVP		1.0
MPC		2.5
ClinPred		0.98	D
GERP RS		3.8
Varity_R		0.95
gMVP		0.90

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: rs1573462811; hg19: chr2-74129548; COSMIC: COSV61829188; COSMIC: COSV61829188;