rs1057516046

Variant names:

• chr2-73913646-G-A
• rs1057516046
• NM_001615.4:c.613G>A
• ACTG2 p.Ala205Thr

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_001615.4(ACTG2):​c.613G>A​(p.Ala205Thr) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,455,658 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 14/24 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A205V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: ACTG2 NM_001615.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.49
• Publications: 1 publications found

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]

ACTG2 Gene-Disease associations (from GenCC):

• visceral myopathy 1

  Inheritance: AR, AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• familial visceral myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• megacystis-microcolon-intestinal hypoperistalsis syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 17 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_001615.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the ACTG2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 35 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 3.3487 (above the threshold of 3.09). Trascript score misZ: 4.3482 (above the threshold of 3.09). GenCC associations: The gene is linked to visceral myopathy 1, megacystis-microcolon-intestinal hypoperistalsis syndrome, familial visceral myopathy.
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 2-73913646-G-A is Pathogenic according to our data. Variant chr2-73913646-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 369682.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001615.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTG2	NM_001615.4	MANE Select	c.613G>A	p.Ala205Thr	missense splice_region	Exon 6 of 9	NP_001606.1	P63267-1
	ACTG2	NM_001199893.2		c.484G>A	p.Ala162Thr	missense splice_region	Exon 5 of 8	NP_001186822.1	P63267-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTG2	ENST00000345517.8	TSL:1 MANE Select	c.613G>A	p.Ala205Thr	missense splice_region	Exon 6 of 9	ENSP00000295137.3	P63267-1
	ACTG2	ENST00000880128.1		c.700G>A	p.Ala234Thr	missense splice_region	Exon 7 of 10	ENSP00000550187.1
	ACTG2	ENST00000958365.1		c.691G>A	p.Ala231Thr	missense splice_region	Exon 7 of 10	ENSP00000628424.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1455658 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 723234

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33330

American (AMR) AF: 0.00 AC: 0 AN: 44360

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26006

East Asian (EAS) AF: 0.00 AC: 0 AN: 39512

South Asian (SAS) AF: 0.00 AC: 0 AN: 85618

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53354

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5754

European-Non Finnish (NFE) AF: 9.03e-7 AC: 1 AN: 1107682

Other (OTH) AF: 0.00 AC: 0 AN: 60042

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	not provided (1)
1	-	-	Visceral myopathy 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PhyloP100		9.5
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.1	D
REVEL	Pathogenic	0.94
Sift4G	Uncertain	0.016	D
Varity_R		0.91
gMVP		0.90
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1057516046;

hg19: chr2-74140773;