NM_206933.4:c.2228G>C

Variant names:

• chr1-216247166-C-G
• rs727504638
• NM_206933.4:c.2228G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_206933.4(USH2A):​c.2228G>C​(p.Gly743Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,776 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. G743E) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: USH2A NM_206933.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.22
• Publications: 0 publications found

Genes affected

USH2A (HGNC:12601): (usherin) This gene encodes a protein that contains laminin EGF motifs, a pentaxin domain, and many fibronectin type III motifs. The protein is found in the basement membrane, and may be important in development and homeostasis of the inner ear and retina. Mutations within this gene have been associated with Usher syndrome type IIa and retinitis pigmentosa. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2008]

USH2A Gene-Disease associations (from GenCC):

• Usher syndrome type 2

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Usher syndrome type 2A

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• retinitis pigmentosa 39

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• retinitis pigmentosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_206933.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.931

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
USH2A	NM_206933.4	c.2228G>C	p.Gly743Ala	missense_variant	Exon 13 of 72	ENST00000307340.8	NP_996816.3
USH2A	NM_007123.6	c.2228G>C	p.Gly743Ala	missense_variant	Exon 13 of 21		NP_009054.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
USH2A	ENST00000307340.8	c.2228G>C	p.Gly743Ala	missense_variant	Exon 13 of 72	1	NM_206933.4	ENSP00000305941.3
USH2A	ENST00000366942.3	c.2228G>C	p.Gly743Ala	missense_variant	Exon 13 of 21	1		ENSP00000355909.3
USH2A	ENST00000674083.1	c.2228G>C	p.Gly743Ala	missense_variant	Exon 13 of 73			ENSP00000501296.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461776 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727194

African (AFR) AF: 0.0000597 AC: 2 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111928

Other (OTH) AF: 0.0000331 AC: 2 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Aug 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt USH2A protein function. ClinVar contains an entry for this variant (Variation ID: 1424569). This variant has not been reported in the literature in individuals affected with USH2A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 743 of the USH2A protein (p.Gly743Ala). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.19	T;.
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.82	T;T
M_CAP	Benign	0.068	D
MetaRNN	Pathogenic	0.93	D;D
MetaSVM	Uncertain	0.21	D
MutationAssessor	Pathogenic	4.2	H;H
PhyloP100		7.2
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-3.9	D;D
REVEL	Uncertain	0.57
Sift	Uncertain	0.026	D;D
Sift4G	Uncertain	0.034	D;D
Polyphen		1.0	D;D
Vest4		0.93
MutPred		0.78		Loss of disorder (P = 0.1119);Loss of disorder (P = 0.1119);
MVP		0.93
MPC		0.24
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.42
gMVP		0.84
Mutation Taster		=38/62	disease causing

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

Other links and lift over

dbSNP: rs727504638; hg19: chr1-216420508; COSMIC: COSV56384365;