rs1553262560

Positions:

• chr1-228158603-A-G
• chr1-228158603-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_020435.4(GJC2):​c.845A>G​(p.Asn282Ser) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,459,660 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 (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: GJC2 NM_020435.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.76

Genes affected

GJC2 (HGNC:17494): (gap junction protein gamma 2) This gene encodes a gap junction protein. Gap junction proteins are members of a large family of homologous connexins and comprise 4 transmembrane, 2 extracellular, and 3 cytoplasmic domains. This gene plays a key role in central myelination and is involved in peripheral myelination in humans. Defects in this gene are the cause of autosomal recessive Pelizaeus-Merzbacher-like disease-1. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a transmembrane_region Helical (size 20) in uniprot entity CXG2_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_020435.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.899

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GJC2	NM_020435.4	c.845A>G	p.Asn282Ser	missense_variant	2/2	ENST00000366714.3	NP_065168.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJC2	ENST00000366714.3	c.845A>G	p.Asn282Ser	missense_variant	2/2	1	NM_020435.4	ENSP00000355675.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459660 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 726232

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Spastic paraplegia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 02, 2017

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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"). This variant has not been reported in the literature in individuals with GJC2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces asparagine with serine at codon 282 of the GJC2 protein (p.Asn282Ser). The asparagine residue is highly conserved and there is a small physicochemical difference between asparagine and serine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Uncertain	0.099	D
BayesDel_noAF	Benign	-0.10
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D
Eigen	Uncertain	0.36
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.90	D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Benign	2.0	M
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.010	D
Sift4G	Uncertain	0.052	T
Polyphen		0.99	D
Vest4		0.65
MutPred		0.51		Loss of stability (P = 0.2028);
MVP		0.97
ClinPred		0.98	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.43
gMVP		0.96

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: rs1553262560; hg19: chr1-228346304;