chr7-146774381-G-C

Variant names:

• chr7-146774381-G-C
• rs758143699
• NM_014141.6:c.208G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_014141.6(CNTNAP2):​c.208G>C​(p.Gly70Arg) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,456,950 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. G70G) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CNTNAP2 NM_014141.6 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.06
• Publications: 0 publications found

Genes affected

CNTNAP2 (HGNC:13830): (contactin associated protein 2) This gene encodes a member of the neurexin family which functions in the vertebrate nervous system as cell adhesion molecules and receptors. This protein, like other neurexin proteins, contains epidermal growth factor repeats and laminin G domains. In addition, it includes an F5/8 type C domain, discoidin/neuropilin- and fibrinogen-like domains, thrombospondin N-terminal-like domains and a putative PDZ binding site. This protein is localized at the juxtaparanodes of myelinated axons, and mediates interactions between neurons and glia during nervous system development and is also involved in localization of potassium channels within differentiating axons. This gene encompasses almost 1.5% of chromosome 7 and is one of the largest genes in the human genome. It is directly bound and regulated by forkhead box protein P2, a transcription factor related to speech and language development. This gene has been implicated in multiple neurodevelopmental disorders, including Gilles de la Tourette syndrome, schizophrenia, epilepsy, autism, ADHD and intellectual disability. [provided by RefSeq, Jul 2017]

CNTNAP2 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AR, AD Classification: DEFINITIVE, NO_KNOWN Submitted by: ClinGen
• cortical dysplasia-focal epilepsy syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Illumina, Labcorp Genetics (formerly Invitae), Orphanet, G2P, Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014141.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CNTNAP2	NM_014141.6	MANE Select	c.208G>C	p.Gly70Arg	missense splice_region	Exon 2 of 24	NP_054860.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CNTNAP2	ENST00000361727.8	TSL:1 MANE Select	c.208G>C	p.Gly70Arg	missense splice_region	Exon 2 of 24	ENSP00000354778.3
	CNTNAP2	ENST00000625365.2	TSL:5	c.208G>C	p.Gly70Arg	missense splice_region	Exon 3 of 4	ENSP00000485955.1
	CNTNAP2	ENST00000636277.1	TSL:5	n.75G>C		splice_region non_coding_transcript_exon	Exon 1 of 2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250552 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1456950 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 725132

African (AFR) AF: 0.00 AC: 0 AN: 33380

American (AMR) AF: 0.0000224 AC: 1 AN: 44682

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26090

East Asian (EAS) AF: 0.00 AC: 0 AN: 39626

South Asian (SAS) AF: 0.00 AC: 0 AN: 86100

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53174

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1107928

Other (OTH) AF: 0.00 AC: 0 AN: 60218

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cortical dysplasia-focal epilepsy syndrome Uncertain:1

Aug 17, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine with arginine at codon 70 of the CNTNAP2 protein (p.Gly70Arg). The glycine residue is weakly conserved and there is a moderate physicochemical difference between glycine and arginine. This variant also falls at the last nucleotide of exon 2 of the CNTNAP2 coding sequence, which is part of the consensus splice site for this exon. Nucleotide substitutions within the consensus splice site are relatively common causes of aberrant splicing (PMID: 17576681, 9536098). This variant is present in population databases (rs758143699, ExAC 0.009%). This variant has not been reported in the literature in individuals with CNTNAP2-related disease. ClinVar contains an entry for this variant (Variation ID: 205298). Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. 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.

not provided Uncertain:1

Sep 16, 2013

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.G70R:GGT>CGT: c.208G>C in CNTNAP2 gene (NM_014141.5). The Gly70Arg missense change has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This variant is a non-conservative amino acid substitution of an uncharged Glycine residue with a positively charged Arginine residue at a position that is conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. However, to our knowledge, there are no reported missense mutations associated with epilepsy in this region of the protein.The variant is found in CHILD-EPI panel(s).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	35
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.082	T
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		9.1
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.010	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.71		Gain of MoRF binding (P = 0.012)
MVP		0.98
MPC		0.55
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.87
gMVP		0.78
Mutation Taster		=33/67	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.96
SpliceAI score (max)		0.010		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: rs758143699; hg19: chr7-146471473;