Genetic Variant CYP27A1:p.Thr339Thr (chr2-218813096-G-A) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_000784.4(CYP27A1):c.1017G>A(p.Thr339Thr) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000715 in 1,607,856 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T339T) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000066 ( 0 hom. )

Consequence

CYP27A1
NM_000784.4 splice_region, synonymous

Scores

Splicing: ADA: 0.9999

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 1.29

Publications

5 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: Myriad Women’s Health, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet, ClinGen

CYP27A1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP27A1	NM_000784.4	MANE Select	c.1017G>A	p.Thr339Thr	splice_region synonymous	Exon 5 of 9	NP_000775.1	Q02318

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CYP27A1	ENST00000258415.9	TSL:1 MANE Select	c.1017G>A	p.Thr339Thr	splice_region synonymous	Exon 5 of 9	ENSP00000258415.4	Q02318
CYP27A1	ENST00000901552.1		c.1017G>A	p.Thr339Thr	splice_region synonymous	Exon 5 of 9	ENSP00000571611.1
CYP27A1	ENST00000901553.1		c.1035G>A	p.Thr345Thr	splice_region synonymous	Exon 5 of 9	ENSP00000571612.1

Frequencies

GnomAD3 genomes

AF:

0.000125

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000338

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000930

AC:

AN:

247182

AF XY:

0.0000672

show subpopulations

Gnomad AFR exome

AF:

0.000377

Gnomad AMR exome

AF:

0.0000585

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000545

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000448

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000660

AC:

AN:

1455552

Hom.:

Cov.:

AF XY:

0.0000719

AC XY:

AN XY:

723124

show subpopulations

African (AFR)

AF:

0.0000902

AC:

AN:

33266

American (AMR)

AF:

0.0000902

AC:

AN:

44346

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25874

East Asian (EAS)

AF:

0.000354

AC:

AN:

39556

South Asian (SAS)

AF:

0.0000233

AC:

AN:

85874

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53206

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5594

European-Non Finnish (NFE)

AF:

0.0000623

AC:

AN:

1107818

Other (OTH)

AF:

0.0000666

AC:

AN:

60018

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

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:

0.000125

AC:

AN:

152304

Hom.:

Cov.:

AF XY:

0.000134

AC XY:

AN XY:

74470

show subpopulations

African (AFR)

AF:

0.000337

AC:

AN:

41544

American (AMR)

AF:

0.00

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5178

South Asian (SAS)

AF:

0.000207

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.580

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:

0.000131

Hom.:

Bravo

AF:

0.000121

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Cholestanol storage disease (5)

not provided (1)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.38

CADD

Uncertain

(source)

DANN

Benign

0.72

PhyloP100

1.3

Mutation Taster

=38/62

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.96

SpliceAI score (max)

0.73

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.73

Position offset: 17

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

Computational scores

Splicing

Publications

Other links and lift over