chr2-218782186-G-GC

Variant names:

• chr2-218782186-G-GC
• rs587778802
• NM_000784.4:c.5dupC

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000784.4(CYP27A1):​c.5dupC​(p.Ala3CysfsTer178) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000289 in 1,384,028 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. A2A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000029 (0 hom.)
• Consequence: CYP27A1 NM_000784.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 0.512
• Publications: 2 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: Myriad Women’s Health, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet, ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 177 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-218782186-G-GC is Pathogenic according to our data. Variant chr2-218782186-G-GC is described in ClinVar as Pathogenic. ClinVar VariationId is 65882.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.5dupC	p.Ala3CysfsTer178	frameshift	Exon 1 of 9	NP_000775.1	Q02318

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP27A1	ENST00000258415.9	TSL:1 MANE Select	c.5dupC	p.Ala3CysfsTer178	frameshift	Exon 1 of 9	ENSP00000258415.4	Q02318
	CYP27A1	ENST00000901552.1		c.5dupC	p.Ala3CysfsTer178	frameshift	Exon 1 of 9	ENSP00000571611.1
	CYP27A1	ENST00000901553.1		c.5dupC	p.Ala3CysfsTer178	frameshift	Exon 1 of 9	ENSP00000571612.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000289 AC: 4 AN: 1384028 Hom.: 0 Cov.: 31 AF XY: 0.00000293 AC XY: 2 AN XY: 683002

African (AFR) AF: 0.00 AC: 0 AN: 31360

American (AMR) AF: 0.00 AC: 0 AN: 35612

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25104

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 79096

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 37508

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4098

European-Non Finnish (NFE) AF: 0.00000371 AC: 4 AN: 1077936

Other (OTH) AF: 0.00 AC: 0 AN: 57642

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	Cholestanol storage disease (4)
3	-	-	not provided (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.51
Mutation Taster		=35/165	disease causing (ClinVar)

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: rs587778802; hg19: chr2-219646909;