NM_201253.3:c.6A>C

Variant names:

• chr1-197268418-A-C
• NM_201253.3:c.6A>C

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_201253.3(CRB1):​c.6A>C​(p.Ala2Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,457,320 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CRB1 NM_201253.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.242
• Publications: 0 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: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P
• retinitis pigmentosa 12

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.85).
• BP6: Variant 1-197268418-A-C is Benign according to our data. Variant chr1-197268418-A-C is described in ClinVar as Likely_benign. ClinVar VariationId is 3754707.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=0.242 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_201253.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRB1	NM_201253.3	MANE Select	c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 12	NP_957705.1	P82279-1
	CRB1	NM_001193640.2		c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 10	NP_001180569.1	P82279-3
	CRB1	NM_001257966.2		c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 10	NP_001244895.1	P82279-5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRB1	ENST00000367400.8	TSL:1 MANE Select	c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 12	ENSP00000356370.3	P82279-1
	CRB1	ENST00000638467.1	TSL:1	c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 11	ENSP00000491102.1	P82279-2
	CRB1	ENST00000367399.6	TSL:1	c.6A>C	p.Ala2Ala	synonymous	Exon 1 of 10	ENSP00000356369.2	P82279-3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1457320 Hom.: 0 Cov.: 28 AF XY: 0.00000138 AC XY: 1 AN XY: 725358

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33338

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26104

East Asian (EAS) AF: 0.00 AC: 0 AN: 39676

South Asian (SAS) AF: 0.00 AC: 0 AN: 86192

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 9.03e-7 AC: 1 AN: 1107884

Other (OTH) AF: 0.00 AC: 0 AN: 60256

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Retinitis pigmentosa 12;C3151202:Leber congenital amaurosis 8 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.85
CADD	Benign	6.2
DANN	Benign	0.52
PhyloP100		0.24
PromoterAI		0.0083	Neutral
Mutation Taster		=100/0	polymorphism

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

hg19: chr1-197237548;