1-205061267-C-T

Position:

• chr1-205061267-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_005076.5(CNTN2):​c.820C>T​(p.Arg274Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000822 in 1,460,254 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. R274H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: CNTN2 NM_005076.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.75

Genes affected

CNTN2 (HGNC:2172): (contactin 2) This gene encodes a member of the contactin family of proteins, part of the immunoglobulin superfamily of cell adhesion molecules. The encoded glycosylphosphatidylinositol (GPI)-anchored neuronal membrane protein plays a role in the proliferation, migration, and axon guidance of neurons of the developing cerebellum. A mutation in this gene may be associated with adult myoclonic epilepsy. [provided by RefSeq, Sep 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 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), CNTN2. . Gene score misZ 2.5878 (greater than the threshold 3.09). Trascript score misZ 3.2882 (greater than threshold 3.09). GenCC has associacion of gene with benign adult familial myoclonic epilepsy, complex neurodevelopmental disorder, epilepsy, familial adult myoclonic, 5.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.85

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CNTN2	NM_005076.5	c.820C>T	p.Arg274Cys	missense_variant	8/23	ENST00000331830.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CNTN2	ENST00000331830.7	c.820C>T	p.Arg274Cys	missense_variant	8/23	1	NM_005076.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000822 AC: 12 AN: 1460254 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 726254

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: 0.00000990

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epilepsy, familial adult myoclonic, 5 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 02, 2021

This sequence change replaces arginine with cysteine at codon 274 of the CNTN2 protein (p.Arg274Cys). The arginine residue is highly conserved and there is a large physicochemical difference between arginine and cysteine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with CNTN2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest 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	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.41	T;T;.
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Pathogenic	0.98	.;.;D
M_CAP	Uncertain	0.15	D
MetaRNN	Pathogenic	0.85	D;D;D
MetaSVM	Uncertain	0.26	D
MutationAssessor	Uncertain	2.3	M;M;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-6.9	.;D;.
REVEL	Pathogenic	0.74
Sift	Pathogenic	0.0	.;D;.
Sift4G	Pathogenic	0.0010	.;D;.
Polyphen		0.99	D;D;.
Vest4		0.88
MutPred		0.58		Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);Loss of MoRF binding (P = 0.0019);
MVP		0.90
MPC		1.5
ClinPred		1.0	D
GERP RS		3.5
Varity_R		0.75
gMVP		0.61

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1473353987; hg19: chr1-205030395; COSMIC: COSV100085038; COSMIC: COSV100085038;