rs199476182

Variant names:

• chr4-186194613-G-A
• rs199476182
• NM_207352.4:c.327+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_207352.4(CYP4V2):​c.327+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,457,386 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CYP4V2 NM_207352.4 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 8.33
• Publications: 4 publications found

Genes affected

CYP4V2 (HGNC:23198): (cytochrome P450 family 4 subfamily V member 2) This gene encodes a member of the cytochrome P450 hemethiolate protein superfamily which are involved in oxidizing various substrates in the metabolic pathway. It is implicated in the metabolism of fatty acid precursors into n-3 polyunsaturated fatty acids. Mutations in this gene result in Bietti crystalline corneoretinal dystrophy. [provided by RefSeq, Jul 2008]

CYP4V2 Gene-Disease associations (from GenCC):

• Bietti crystalline corneoretinal dystrophy

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Illumina, Orphanet, Labcorp Genetics (formerly Invitae), G2P, ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-186194613-G-A is Pathogenic according to our data. Variant chr4-186194613-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 39262.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP4V2	NM_207352.4	c.327+1G>A		splice_donor_variant, intron_variant	Intron 2 of 10	ENST00000378802.5	NP_997235.3
CYP4V2	XM_005262935.5	c.327+1G>A		splice_donor_variant, intron_variant	Intron 2 of 10		XP_005262992.1
CYP4V2	XM_047450077.1	c.17+1G>A		splice_donor_variant, intron_variant	Intron 1 of 8		XP_047306033.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP4V2	ENST00000378802.5	c.327+1G>A		splice_donor_variant, intron_variant	Intron 2 of 10	1	NM_207352.4	ENSP00000368079.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1457386 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725336

African (AFR) AF: 0.00 AC: 0 AN: 33380

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39674

South Asian (SAS) AF: 0.00 AC: 0 AN: 86120

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1107972

Other (OTH) AF: 0.00 AC: 0 AN: 60240

GnomAD4 genome Cov.: 33

Alfa AF: 0.000196 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Bietti crystalline corneoretinal dystrophy Pathogenic:1

Apr 12, 2012

GeneReviews

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

not provided Pathogenic:1

Aug 20, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 39262). Disruption of this splice site has been observed in individual(s) with Bietti crystalline corneoretinal dystrophy (PMID: 15042513, 27658286, 28763560). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in intron 2 of the CYP4V2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CYP4V2 are known to be pathogenic (PMID: 15042513, 25118264). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.23
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		8.3
GERP RS		5.2
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs199476182; hg19: chr4-187115767;