X-71223168-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP5 BP4

The NM_001097642.3(GJB1):c.-16-524C>G variant causes a intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 22)
• Consequence: GJB1 NM_001097642.3 intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 3.82

Genes affected

GJB1 (HGNC:4283): (gap junction protein beta 1) This gene encodes a member of the gap junction protein family. The gap junction proteins are membrane-spanning proteins that assemble to form gap junction channels that facilitate the transfer of ions and small molecules between cells. According to sequence similarities at the nucleotide and amino acid levels, the gap junction proteins are divided into two categories, alpha and beta. Mutations in this gene cause X-linked Charcot-Marie-Tooth disease, an inherited peripheral neuropathy. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-71223168-C-G is Pathogenic according to our data. Variant chrX-71223168-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 406227.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Uncertain_significance=1}.
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.42).. Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GJB1	NM_001097642.3	c.-16-524C>G		intron_variant
GJB1	XM_011530907.3	c.-17+402C>G		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJB1	ENST00000374029.2	c.-16-524C>G		intron_variant		5		P1
GJB1	ENST00000447581.2	c.-17+402C>G		intron_variant		5		P1
GJB1	ENST00000645009.2	c.-16-524C>G		intron_variant				P1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 22

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Charcot-Marie-Tooth Neuropathy X Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Oct 28, 2022

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 406227). This variant is also known as c.-184C>G or c.-540C>G. This variant has been observed in individual(s) with clinical features of Charcot-Marie-Tooth disease (PMID: 24078732; Invitae). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the gnomAD database. This variant occurs in a non-coding region of the GJB1 gene. It does not change the encoded amino acid sequence of the GJB1 protein. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 02, 2023

No data available from control populations to assess the frequency of this variant; Other regulatory variants in GJB1 have been reported in the Human Gene Mutation Database in individuals with CMT (Stenson et al., 2014).; This variant is not expected to alter the ATG initiation codon. In the absence of RNA/functional studies, the actual effect of this sequence change in this individual is unknown.; This variant is associated with the following publications: (PMID: 24078732) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.42
Cadd	Uncertain	23
Dann	Benign	0.82

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: rs1060501001; hg19: chrX-70443018;