2-218809676-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM1BS2

The NM_000784.4(CYP27A1):c.355C>T(p.Arg119Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000128 in 1,614,114 control chromosomes in the GnomAD database, including 3 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R119Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00013 ( 3 hom. )

Consequence

CYP27A1
NM_000784.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:1

Conservation

PhyloP100: 0.474

Publications

2 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: Likely_benign. The variant received -2 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000784.4

BS2

High Homozygotes in GnomAdExome4 at 3 AR gene

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000784.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP27A1	NM_000784.4	MANE Select	c.355C>T	p.Arg119Trp	missense	Exon 2 of 9	NP_000775.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CYP27A1	ENST00000258415.9	TSL:1 MANE Select	c.355C>T	p.Arg119Trp	missense	Exon 2 of 9	ENSP00000258415.4
CYP27A1	ENST00000411688.1	TSL:3	c.73C>T	p.Arg25Trp	missense	Exon 2 of 5	ENSP00000392671.1
CYP27A1	ENST00000494263.5	TSL:2	n.789C>T		non_coding_transcript_exon	Exon 2 of 7

Frequencies

GnomAD3 genomes

AF:

0.000118

AC:

AN:

152106

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000965

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00144

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000829

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.000479

GnomAD2 exomes

AF:

0.000219

AC:

AN:

251414

AF XY:

0.000280

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00189

Gnomad EAS exome

AF:

0.000217

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000129

AC:

188

AN:

1461890

Hom.:

Cov.:

AF XY:

0.000160

AC XY:

116

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00214

AC:

AN:

26136

East Asian (EAS)

AF:

0.000554

AC:

AN:

39700

South Asian (SAS)

AF:

0.000869

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000216

AC:

AN:

1112008

Other (OTH)

AF:

0.000149

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.502

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.000118

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.000134

AC XY:

AN XY:

74414

show subpopulations

African (AFR)

AF:

0.0000963

AC:

AN:

41552

American (AMR)

AF:

0.0000654

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00144

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.000830

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

290

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68012

Other (OTH)

AF:

0.000474

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.503

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000118

Hom.:

Bravo

AF:

0.000106

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000206

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Breakthrough Genomics, Breakthrough Genomics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:not provided

Oct 08, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

May 15, 2018

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Cholestanol storage disease

Uncertain:2

Aug 23, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 119 of the CYP27A1 protein (p.Arg119Trp). This variant is present in population databases (rs369294392, gnomAD 0.2%). This variant has not been reported in the literature in individuals affected with CYP27A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 447230). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CYP27A1 protein function. 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.

Nov 11, 2019

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

Cardiovascular phenotype

Benign:1

Aug 25, 2025

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.34

BayesDel_addAF

Uncertain

0.042

BayesDel_noAF

Pathogenic

0.21

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.87

Eigen

Uncertain

0.59

Eigen_PC

Uncertain

0.51

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.96

M_CAP

Uncertain

0.14

MetaRNN

Uncertain

0.64

MetaSVM

Uncertain

0.23

MutationAssessor

Pathogenic

3.4

PhyloP100

0.47

PrimateAI

Uncertain

0.57

PROVEAN

Pathogenic

-7.3

REVEL

Pathogenic

0.77

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.94

MVP

0.93

MPC

0.73

ClinPred

0.74

GERP RS

3.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.97

gMVP

0.86

Mutation Taster

=21/79

disease causing

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over