2-218782191-G-A

Variant names:

• chr2-218782191-G-A
• rs971599666
• NM_000784.4:c.9G>A

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 2P and 13B. PM2 BP4_Strong BP6_Very_Strong BP7

The NM_000784.4(CYP27A1):​c.9G>A​(p.Ala3Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000722 in 1,384,744 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 (★★). Synonymous variant affecting the same amino acid position (i.e. A3A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.2e-7 (0 hom.)
• Consequence: CYP27A1 NM_000784.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: -0.0460
• Publications: 0 publications found

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

ACMG classification

Our verdict: Benign. The variant received -11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.67).
• BP6: Variant 2-218782191-G-A is Benign according to our data. Variant chr2-218782191-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 1768933.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.046 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP27A1	NM_000784.4	c.9G>A	p.Ala3Ala	synonymous_variant	Exon 1 of 9	ENST00000258415.9	NP_000775.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP27A1	ENST00000258415.9	c.9G>A	p.Ala3Ala	synonymous_variant	Exon 1 of 9	1	NM_000784.4	ENSP00000258415.4
CYP27A1	ENST00000445971.1	n.9G>A		non_coding_transcript_exon_variant	Exon 1 of 5	5		ENSP00000404945.1
CYP27A1	ENST00000466602.1	n.18G>A		non_coding_transcript_exon_variant	Exon 1 of 3	2
CYP27A1	ENST00000494263.5	n.443G>A		non_coding_transcript_exon_variant	Exon 1 of 7	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000750 AC: 1 AN: 133360 AF XY: 0.00

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: 0.00

Gnomad OTH exome AF: 0.000248

GnomAD4 exome AF: 7.22e-7 AC: 1 AN: 1384744 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 683408

African (AFR) AF: 0.0000319 AC: 1 AN: 31366

American (AMR) AF: 0.00 AC: 0 AN: 35626

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25110

East Asian (EAS) AF: 0.00 AC: 0 AN: 35672

South Asian (SAS) AF: 0.00 AC: 0 AN: 79110

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 38110

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4114

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1077988

Other (OTH) AF: 0.00 AC: 0 AN: 57648

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cholestanol storage disease Benign:1

Jul 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype Benign:1

Jul 12, 2020

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 v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	12
DANN	Benign	0.75
PhyloP100		-0.046
PromoterAI		-0.097	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
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

dbSNP: rs971599666; hg19: chr2-219646914;