2-73901415-T-A

Variant names:

• chr2-73901415-T-A
• rs1461116147
• NM_001615.4:c.104T>A

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_001615.4(ACTG2):​c.104T>A​(p.Ile35Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,174 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I35T) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 34)
• Consequence: ACTG2 NM_001615.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.96
• 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: Likely_pathogenic. The variant received 9 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, 1 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: MetaRNN computational evidence supports a deleterious effect, 0.957

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.104T>A	p.Ile35Asn	missense	Exon 2 of 9	NP_001606.1	P63267-1
	ACTG2	NM_001199893.2		c.104T>A	p.Ile35Asn	missense	Exon 2 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.104T>A	p.Ile35Asn	missense	Exon 2 of 9	ENSP00000295137.3	P63267-1
	ACTG2	ENST00000409918.5	TSL:1	c.104T>A	p.Ile35Asn	missense	Exon 2 of 4	ENSP00000387182.1	B8ZZJ2
	ACTG2	ENST00000880128.1		c.104T>A	p.Ile35Asn	missense	Exon 2 of 10	ENSP00000550187.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152174 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 35

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152174 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 74332

African (AFR) AF: 0.0000241 AC: 1 AN: 41448

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10598

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68044

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	28
DANN	Uncertain	0.97
DEOGEN2	Pathogenic	0.81	D
Eigen	Pathogenic	0.73
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.78	T
M_CAP	Pathogenic	0.75	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		8.0
PrimateAI	Pathogenic	0.92	D
PROVEAN	Uncertain	-3.0	D
REVEL	Pathogenic	0.95
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.91
MutPred		0.83		Gain of disorder (P = 0.007)
MVP		1.0
MPC		3.2
ClinPred		0.99	D
GERP RS		3.9
Varity_R		0.96
gMVP		0.95
Mutation Taster		=55/45	polymorphism

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: rs1461116147; hg19: chr2-74128542;