1-34761343-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_153212.3(GJB4):c.89T>C(p.Ile30Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: GJB4 NM_153212.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.97

Genes affected

GJB4 (HGNC:4286): (gap junction protein beta 4) This gene encodes a transmembrane connexin protein that is a component of gap junctions. Mutations in this gene have been associated with erythrokeratodermia variabilis, progressive symmetric erythrokeratoderma and hearing impairment. [provided by RefSeq, Dec 2009]

SMIM12 (HGNC:25154): (small integral membrane protein 12) Predicted to be integral component of membrane. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.847

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GJB4	NM_153212.3	c.89T>C	p.Ile30Thr	missense_variant	2/2	ENST00000339480.3
GJB4	XM_011540679.3	c.89T>C	p.Ile30Thr	missense_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJB4	ENST00000339480.3	c.89T>C	p.Ile30Thr	missense_variant	2/2	2	NM_153212.3	P1
SMIM12	ENST00000426886.1	c.208-42934A>G		intron_variant, NMD_transcript_variant		1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 17, 2023

The c.89T>C (p.I30T) alteration is located in exon 2 (coding exon 1) of the GJB4 gene. This alteration results from a T to C substitution at nucleotide position 89, causing the isoleucine (I) at amino acid position 30 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.56
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
Cadd	Uncertain	24
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.78	T
M_CAP	Pathogenic	0.46	D
MetaRNN	Pathogenic	0.85	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	M
MutationTaster	Benign	1.0	D
PrimateAI	Benign	0.45	T
PROVEAN	Uncertain	-3.9	D
REVEL	Pathogenic	0.87
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		0.50	P
Vest4		0.36
MutPred		0.87		Loss of stability (P = 0.0164);
MVP		0.84
MPC		0.42
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.63
gMVP		0.71

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: rs994588701; hg19: chr1-35226944;