19-47836338-G-T

Variant names:

• chr19-47836338-G-T
• rs61748438
• NM_000554.6:c.196G>T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000554.6(CRX):​c.196G>T​(p.Val66Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,890 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. V66I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CRX NM_000554.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.92
• Publications: 0 publications found

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]

CRX Gene-Disease associations (from GenCC):

• cone-rod dystrophy 2

  Inheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics
• hereditary macular dystrophy

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• Leber congenital amaurosis 7

  Inheritance: AD, AR, SD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• cone-rod dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Leber congenital amaurosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• retinitis pigmentosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 3 uncertain in NM_000554.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.833

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRX	NM_000554.6	c.196G>T	p.Val66Phe	missense_variant	Exon 3 of 4	ENST00000221996.12	NP_000545.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRX	ENST00000221996.12	c.196G>T	p.Val66Phe	missense_variant	Exon 3 of 4	2	NM_000554.6	ENSP00000221996.5
CRX	ENST00000613299.1	c.100+1795G>T		intron_variant	Intron 2 of 2	3		ENSP00000478106.1
CRX	ENST00000556527.1	n.*9G>T		downstream_gene_variant		1
CRX	ENST00000566686.5	c.*24G>T		downstream_gene_variant		5		ENSP00000457808.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461890 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727246

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60396

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

Feb 24, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CRX-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. 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. This sequence change replaces valine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 66 of the CRX protein (p.Val66Phe).

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.040
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.89	D;D
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Benign	0.0	.;D
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.83	D;D
MetaSVM	Uncertain	0.79	D
MutationAssessor	Uncertain	2.4	M;M
PhyloP100		4.9
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-2.7	D;D
REVEL	Pathogenic	0.68
Sift	Uncertain	0.022	D;D
Sift4G	Uncertain	0.022	D;D
Vest4		0.71
ClinPred		0.96	D
GERP RS		2.2
Varity_R		0.44
gMVP		0.81
Mutation Taster		=64/36	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs61748438; hg19: chr19-48339595;