1-197427559-C-G

Variant names:

• chr1-197427559-C-G
• rs28939720
• NM_201253.3:c.2234C>G

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_201253.3(CRB1):​c.2234C>G​(p.Thr745Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,688 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. T745K) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CRB1 NM_201253.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 5.67
• Publications: 45 publications found

Genes affected

CRB1 (HGNC:2343): (crumbs cell polarity complex component 1) This gene encodes a protein which is similar to the Drosophila crumbs protein and localizes to the inner segment of mammalian photoreceptors. In Drosophila crumbs localizes to the stalk of the fly photoreceptor and may be a component of the molecular scaffold that controls proper development of polarity in the eye. Mutations in this gene are associated with a severe form of retinitis pigmentosa, RP12, and with Leber congenital amaurosis. Alternate splicing results in multiple transcript variants, some protein coding and some non-protein coding.[provided by RefSeq, Apr 2012]

CRB1 Gene-Disease associations (from GenCC):

• hereditary macular dystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
• Leber congenital amaurosis 8

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine
• retinitis pigmentosa 12

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• Leber congenital amaurosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• nanophthalmia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• pigmented paravenous retinochoroidal atrophy

  Inheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: G2P, Orphanet
• retinitis pigmentosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_201253.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-197427559-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 973930.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 168 curated pathogenic missense variants (we use a threshold of 10). The gene has 18 curated benign missense variants. Gene score misZ: -1.2832 (below the threshold of 3.09). Trascript score misZ: 0.62189 (below the threshold of 3.09). GenCC associations: The gene is linked to Leber congenital amaurosis 8, retinitis pigmentosa 12, pigmented paravenous retinochoroidal atrophy, hereditary macular dystrophy, retinitis pigmentosa, Leber congenital amaurosis, nanophthalmia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRB1	NM_201253.3	c.2234C>G	p.Thr745Arg	missense_variant	Exon 7 of 12	ENST00000367400.8	NP_957705.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRB1	ENST00000367400.8	c.2234C>G	p.Thr745Arg	missense_variant	Exon 7 of 12	1	NM_201253.3	ENSP00000356370.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250914 AF XY: 0.00000737

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461688 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727142

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44696

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.0000232 AC: 2 AN: 86236

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53384

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111922

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Leber congenital amaurosis 8 Pathogenic:1

-

Laboratory of Genetics in Ophthalmology, Institut Imagine

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

not specified Uncertain:1

Mar 14, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CRB1 c.2234C>G (p.Thr745Arg) results in a non-conservative amino acid change located in the Laminin G domain (IPR001791) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 250914 control chromosomes (gnomAD). To our knowledge, no occurrence of c.2234C>G in individuals affected with Retinal Dystrophy and no experimental evidence demonstrating its impact on protein function have been reported. Other missense changes affecting this amino acid have been found in association with disease, one of which (p.Thr745Met) has been determined to be pathogenic, suggesting this may be a functionally important residue. ClinVar contains an entry for this variant (Variation ID: 973910). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.69
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.38
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.68	D;.;D;.;T
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.32
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D;.;D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Pathogenic	0.80	D
MutationAssessor	Pathogenic	3.1	.;M;M;.;.
PhyloP100		5.7
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-4.7	D;.;D;D;D
REVEL	Pathogenic	0.80
Sift	Uncertain	0.0010	D;.;D;D;D
Sift4G	Uncertain	0.0020	D;.;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.78
MutPred		0.84		.;Loss of glycosylation at S749 (P = 0.3015);Loss of glycosylation at S749 (P = 0.3015);.;.;
MVP		0.95
MPC		0.25
ClinPred		0.99	D
GERP RS		4.8
Varity_R		0.65
gMVP		0.96
Mutation Taster		=4/96	disease causing (ClinVar)

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: rs28939720; hg19: chr1-197396689;