19-47834503-C-G

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_000554.6(CRX):c.60C>G(p.Gly20=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G20G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CRX NM_000554.6 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.167

Genes affected

CRX (HGNC:2383): (cone-rod homeobox) The protein encoded by this gene is a photoreceptor-specific transcription factor which plays a role in the differentiation of photoreceptor cells. This homeodomain protein is necessary for the maintenance of normal cone and rod function. Mutations in this gene are associated with photoreceptor degeneration, Leber congenital amaurosis type III and the autosomal dominant cone-rod dystrophy 2. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some variants has not been determined. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.42).
• BP7: Synonymous conserved (PhyloP=-0.167 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRX	NM_000554.6	c.60C>G	p.Gly20=	synonymous_variant	2/4	ENST00000221996.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRX	ENST00000221996.12	c.60C>G	p.Gly20=	synonymous_variant	2/4	2	NM_000554.6	P1
CRX	ENST00000556527.1	n.78-1740C>G		intron_variant, non_coding_transcript_variant		1
CRX	ENST00000566686.5	c.60C>G	p.Gly20=	synonymous_variant	2/3	5
CRX	ENST00000613299.1	c.60C>G	p.Gly20=	synonymous_variant	2/3	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Leber congenital amaurosis 7;C3489532:Cone-rod dystrophy 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 28, 2022

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 is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 1496893). This variant has been observed in individual(s) with retinal dystrophy (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects codon 20 of the CRX mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the CRX protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.42
Cadd	Benign	9.0
Dann	Benign	0.77

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: rs769017861; hg19: chr19-48337760;