chr2-218809768-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000784.4(CYP27A1):c.446+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 0.00000496 in 1,612,478 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: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

CYP27A1
NM_000784.4 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 9.75

Publications

6 publications found

Variant links:

Genes affected

CYP27A1 (HGNC:2605): (cytochrome P450 family 27 subfamily A member 1) This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This mitochondrial protein oxidizes cholesterol intermediates as part of the bile synthesis pathway. Since the conversion of cholesterol to bile acids is the major route for removing cholesterol from the body, this protein is important for overall cholesterol homeostasis. Mutations in this gene cause cerebrotendinous xanthomatosis, a rare autosomal recessive lipid storage disease. [provided by RefSeq, Jul 2008]

CYP27A1 Gene-Disease associations (from GenCC):

cerebrotendinous xanthomatosis
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Genomics England PanelApp, G2P

CYP27A1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 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 2-218809768-G-A is Pathogenic according to our data. Variant chr2-218809768-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 65871.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP27A1	NM_000784.4 link	c.446+1G>A		splice_donor_variant, intron_variant	Intron 2 of 8	ENST00000258415.9	NP_000775.1	Q02318

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP27A1	ENST00000258415.9 link	c.446+1G>A		splice_donor_variant, intron_variant	Intron 2 of 8	1	NM_000784.4	ENSP00000258415.4		Q02318

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000400

AC:

AN:

249866

AF XY:

0.00000741

show subpopulations

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:

0.00000888

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1460288

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726190

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33440

American (AMR)

AF:

0.00

AC:

AN:

44672

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26066

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39650

South Asian (SAS)

AF:

0.00

AC:

AN:

86148

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53360

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1110890

Other (OTH)

AF:

0.00

AC:

AN:

60306

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74366

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41448

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cholestanol storage disease

Pathogenic:7

Apr 13, 2023

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

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: CYP27A1 c.446+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a canonical 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 249866 control chromosomes (gnomAD). c.446+1G>A has been reported in the literature as a biallelic genotype in individuals affected with Cerebrotendinous Xanthomatosis (e.g. Verrips_2000, Dutta_2015, Zabarioglu_2019). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five ClinVar submitters have assessed the variant since 2014: all five classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Feb 13, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change affects a donor splice site in intron 2 of the CYP27A1 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 CYP27A1 are known to be pathogenic (PMID: 9392430, 10775536, 26937392). This variant is present in population databases (rs587778797, gnomAD 0.0009%). Disruption of this splice site has been observed in individuals with cerebrotendinous xanthomatosis (PMID: 10775536, 26937392). ClinVar contains an entry for this variant (Variation ID: 65871). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Aug 01, 2013

GeneReviews

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:curation

- -

Mar 15, 2018

Counsyl

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Nov 24, 2020

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Oct 06, 2022

Revvity Omics, Revvity

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

May 10, 2018

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.1

FATHMM_MKL

Pathogenic

1.0

PhyloP100

9.8

GERP RS

5.6

Mutation Taster

=1/99

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.98

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.98

Position offset: -1

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over