chr14-68874955-G-C

Position:

• chr14-68874955-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001130004.2(ACTN1):​c.2649C>G​(p.Ile883Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,378 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACTN1 NM_001130004.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.12

Genes affected

ACTN1 (HGNC:163): (actinin alpha 1) Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of cytoskeletal proteins, including the alpha and beta spectrins and dystrophins. Alpha actinin is an actin-binding protein with multiple roles in different cell types. In nonmuscle cells, the cytoskeletal isoform is found along microfilament bundles and adherens-type junctions, where it is involved in binding actin to the membrane. In contrast, skeletal, cardiac, and smooth muscle isoforms are localized to the Z-disc and analogous dense bodies, where they help anchor the myofibrillar actin filaments. This gene encodes a nonmuscle, cytoskeletal, alpha actinin isoform and maps to the same site as the structurally similar erythroid beta spectrin gene. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), ACTN1. . Gene score misZ: 3.3621 (greater than the threshold 3.09). Trascript score misZ: 5.1933 (greater than threshold 3.09). The gene has 22 curated pathogenic missense variants (we use a threshold of 10). The gene has 8 curated benign missense variants. GenCC has associacion of the gene with autosomal dominant macrothrombocytopenia, platelet-type bleeding disorder 15.
• BP4: Computational evidence support a benign effect (MetaRNN=0.36965007).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ACTN1	NM_001130004.2	c.2649C>G	p.Ile883Met	missense_variant	22/22	ENST00000394419.9	NP_001123476.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ACTN1	ENST00000394419.9	c.2649C>G	p.Ile883Met	missense_variant	22/22	1	NM_001130004.2	ENSP00000377941.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461378 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726986

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 27, 2024

This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 883 of the ACTN1 protein (p.Ile883Met). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ACTN1-related conditions. 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 disruptive. 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	Benign	0.14
BayesDel_addAF	Benign	-0.022	T
BayesDel_noAF	Benign	-0.27
CADD	Benign	23
DANN	Benign	0.96
DEOGEN2	Benign	0.28	T;.;.;T;.
Eigen	Benign	-0.049
Eigen_PC	Benign	-0.080
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Uncertain	0.95	D;D;D;D;D
M_CAP	Benign	0.037	D
MetaRNN	Benign	0.37	T;T;T;T;T
MetaSVM	Benign	-0.73	T
MutationAssessor	Uncertain	2.4	M;.;.;.;.
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-2.1	N;N;N;N;N
REVEL	Benign	0.24
Sift	Benign	0.050	D;D;D;T;D
Sift4G	Uncertain	0.057	T;T;T;T;D
Polyphen		0.0030	B;.;B;.;.
Vest4		0.40
MutPred		0.55		Gain of disorder (P = 0.0349);.;.;.;.;
MVP		0.55
MPC		0.10
ClinPred		0.81	D
GERP RS		0.80
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.31
gMVP		0.62

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: rs1365405872; hg19: chr14-69341672;