15-74347899-C-T

Variant names:

• chr15-74347899-C-T
• rs886041759
• NM_000781.3:c.425+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000781.3(CYP11A1):​c.425+1G>A variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000137 in 1,461,794 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CYP11A1 NM_000781.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 6.55
• Publications: 2 publications found

Genes affected

CYP11A1 (HGNC:2590): (cytochrome P450 family 11 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 protein localizes to the mitochondrial inner membrane and catalyzes the conversion of cholesterol to pregnenolone, the first and rate-limiting step in the synthesis of the steroid hormones. Two transcript variants encoding different isoforms have been found for this gene. The cellular location of the smaller isoform is unclear since it lacks the mitochondrial-targeting transit peptide. [provided by RefSeq, Jul 2008]

CYP11A1 Gene-Disease associations (from GenCC):

• Congenital adrenal insufficiency with 46, XY sex reversal OR 46,XY disorder of sex development-adrenal insufficiency due to CYP11A1 deficiency

  Inheritance: AR, AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• inherited isolated adrenal insufficiency due to partial CYP11A1 deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.099616855 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-74347899-C-T is Pathogenic according to our data. Variant chr15-74347899-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 280582.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000781.3. 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
	CYP11A1	NM_000781.3	MANE Select	c.425+1G>A		splice_donor intron	N/A	NP_000772.2
	CYP11A1	NM_001099773.2		c.-50+1G>A		splice_donor intron	N/A	NP_001093243.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP11A1	ENST00000268053.11	TSL:1 MANE Select	c.425+1G>A		splice_donor intron	N/A	ENSP00000268053.6
	CYP11A1	ENST00000358632.8	TSL:2	c.-50+1G>A		splice_donor intron	N/A	ENSP00000351455.4
	CYP11A1	ENST00000566674.5	TSL:5	c.-50+1G>A		splice_donor intron	N/A	ENSP00000456941.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461794 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727184

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

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5754

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111962

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

May 10, 2016

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.425+1G>A pathogenic variant in the CYP11A1 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. This splice site variant destroys the canonical splice donor site in intron 2. It is predicted to cause abnormal gene splicing resulting in an in-frame protein product with an abnormal message. The c.425+1G>A variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.425+1G>A as a pathogenic variant.

Dec 18, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 2 of the CYP11A1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CYP11A1 are known to be pathogenic (PMID: 15507506, 22435390, 27855232, 229968487). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with clinical features of congenital adrenal insufficiency and/or congenital adrenal insufficiency (PMID: 29178636). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 280582). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	32
DANN	Uncertain	1.0
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		6.6
GERP RS		4.5
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs886041759; hg19: chr15-74640240;