chr2-218809624-GC-G

Variant names:

• chr2-218809624-GC-G
• rs587778790
• NM_000784.4:c.305delC

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_000784.4(CYP27A1):​c.305delC​(p.Pro102LeufsTer5) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (no stars). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CYP27A1 NM_000784.4 frameshift
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 0.0410
• Publications: 3 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 11 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-218809624-GC-G is Pathogenic according to our data. Variant chr2-218809624-GC-G is described in ClinVar as Pathogenic. ClinVar VariationId is 65856.Status of the report is no_assertion_criteria_provided, 0 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.305delC	p.Pro102LeufsTer5	frameshift	Exon 2 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.305delC	p.Pro102LeufsTer5	frameshift	Exon 2 of 9	ENSP00000258415.4	Q02318
	CYP27A1	ENST00000901552.1		c.305delC	p.Pro102LeufsTer5	frameshift	Exon 2 of 9	ENSP00000571611.1
	CYP27A1	ENST00000901553.1		c.305delC	p.Pro102LeufsTer5	frameshift	Exon 2 of 9	ENSP00000571612.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251462 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461892 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727246

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000504 AC: 2 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Cholestanol storage disease (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.041
Mutation Taster		=4/196	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: rs587778790; hg19: chr2-219674347;