5-138924596-A-C

Variant names:

• chr5-138924596-A-C
• rs1060502220
• NM_001903.5:c.1633A>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001903.5(CTNNA1):​c.1633A>C​(p.Ile545Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I545T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CTNNA1 NM_001903.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.51
• Publications: 0 publications found

Genes affected

CTNNA1 (HGNC:2509): (catenin alpha 1) This gene encodes a member of the catenin family of proteins that play an important role in cell adhesion process by connecting cadherins located on the plasma membrane to the actin filaments inside the cell. The encoded mechanosensing protein contains three vinculin homology domains and undergoes conformational changes in response to cytoskeletal tension, resulting in the reconfiguration of cadherin-actin filament connections. Certain mutations in this gene cause butterfly-shaped pigment dystrophy. [provided by RefSeq, May 2016]

CTNNA1 Gene-Disease associations (from GenCC):

• CTNNA1-related diffuse gastric and lobular breast cancer syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• patterned macular dystrophy 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• patterned macular dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary nonpolyposis colon cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CTNNA1	NM_001903.5	c.1633A>C	p.Ile545Leu	missense_variant	Exon 12 of 18	ENST00000302763.12	NP_001894.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CTNNA1	ENST00000302763.12	c.1633A>C	p.Ile545Leu	missense_variant	Exon 12 of 18	1	NM_001903.5	ENSP00000304669.7

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Apr 23, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine with leucine at codon 545 of the CTNNA1 protein (p.Ile545Leu). The isoleucine residue is highly conserved and there is a small physicochemical difference between isoleucine and leucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CTNNA1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Oct 18, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.I545L variant (also known as c.1633A>C), located in coding exon 11 of the CTNNA1 gene, results from an A to C substitution at nucleotide position 1633. The isoleucine at codon 545 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Uncertain	0.068	T
BayesDel_noAF	Benign	-0.14
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.040	T;T;T;.
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;.;D
M_CAP	Benign	0.025	D
MetaRNN	Uncertain	0.63	D;D;D;D
MetaSVM	Benign	-0.38	T
MutationAssessor	Uncertain	2.8	.;M;.;.
PhyloP100		7.5
PrimateAI	Pathogenic	0.83	D
PROVEAN	Benign	-1.7	.;N;N;N
REVEL	Benign	0.24
Sift	Uncertain	0.0020	.;D;D;D
Sift4G	Uncertain	0.052	T;D;T;T
Polyphen		0.88	P;D;P;.
Vest4		0.66
MutPred		0.69		Loss of catalytic residue at I545 (P = 0.0226);Loss of catalytic residue at I545 (P = 0.0226);Loss of catalytic residue at I545 (P = 0.0226);.;
MVP		0.64
MPC		2.1
ClinPred		0.95	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.71
gMVP		0.82
Mutation Taster		=61/39	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: rs1060502220; hg19: chr5-138260285;