NM_000500.9:c.293-13C>G

Variant names:

• chr6-32039081-C-G
• rs6467
• NM_000500.9:c.293-13C>G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PP5_Very_Strong

The NM_000500.9(CYP21A2):​c.293-13C>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00216 in 151,236 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.0022 (1 hom., cov: 29)
  • Exomes 𝑓: 0.0024 (6 hom.)
  • Failed GnomAD Quality Control
• Consequence: CYP21A2 NM_000500.9 intron
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:34 O:1
• Conservation: PhyloP100: -0.233

Genes affected

CYP21A2 (HGNC:2600): (cytochrome P450 family 21 subfamily A member 2) 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 endoplasmic reticulum and hydroxylates steroids at the 21 position. Its activity is required for the synthesis of steroid hormones including cortisol and aldosterone. Mutations in this gene cause congenital adrenal hyperplasia. A related pseudogene is located near this gene; gene conversion events involving the functional gene and the pseudogene are thought to account for many cases of steroid 21-hydroxylase deficiency. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PP5: Variant 6-32039081-C-G is Pathogenic according to our data. Variant chr6-32039081-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 12155.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr6-32039081-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP21A2	NM_000500.9	c.293-13C>G		intron_variant	Intron 2 of 9	ENST00000644719.2	NP_000491.4
CYP21A2	NM_001368143.2	c.-126C>G		5_prime_UTR_variant	Exon 3 of 10		NP_001355072.1
CYP21A2	NM_001368144.2	c.-126C>G		5_prime_UTR_variant	Exon 2 of 9		NP_001355073.1
CYP21A2	NM_001128590.4	c.203-13C>G		intron_variant	Intron 1 of 8		NP_001122062.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP21A2	ENST00000644719.2	c.293-13C>G		intron_variant	Intron 2 of 9		NM_000500.9	ENSP00000496625.1

Frequencies

GnomAD3 genomes AF: 0.00216 AC: 327 AN: 151120 Hom.: 1 Cov.: 29

Gnomad AFR AF: 0.00182

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00158

Gnomad ASJ AF: 0.00461

Gnomad EAS AF: 0.00138

Gnomad SAS AF: 0.00272

Gnomad FIN AF: 0.000669

Gnomad MID AF: 0.00318

Gnomad NFE AF: 0.00263

Gnomad OTH AF: 0.00289

GnomAD3 exomes AF: 0.00226 AC: 501 AN: 221616 Hom.: 0 AF XY: 0.00242 AC XY: 289 AN XY: 119232

Gnomad AFR exome AF: 0.00155

Gnomad AMR exome AF: 0.00204

Gnomad ASJ exome AF: 0.00371

Gnomad EAS exome AF: 0.00210

Gnomad SAS exome AF: 0.00242

Gnomad FIN exome AF: 0.000831

Gnomad NFE exome AF: 0.00261

Gnomad OTH exome AF: 0.00146

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00245 AC: 3525 AN: 1440550 Hom.: 6 Cov.: 74 AF XY: 0.00237 AC XY: 1691 AN XY: 714484

Gnomad4 AFR exome AF: 0.00151

Gnomad4 AMR exome AF: 0.00199

Gnomad4 ASJ exome AF: 0.00378

Gnomad4 EAS exome AF: 0.00247

Gnomad4 SAS exome AF: 0.00279

Gnomad4 FIN exome AF: 0.00107

Gnomad4 NFE exome AF: 0.00249

Gnomad4 OTH exome AF: 0.00248

GnomAD4 genome AF: 0.00216 AC: 327 AN: 151236 Hom.: 1 Cov.: 29 AF XY: 0.00207 AC XY: 153 AN XY: 73856

Gnomad4 AFR AF: 0.00182

Gnomad4 AMR AF: 0.00158

Gnomad4 ASJ AF: 0.00461

Gnomad4 EAS AF: 0.00138

Gnomad4 SAS AF: 0.00272

Gnomad4 FIN AF: 0.000669

Gnomad4 NFE AF: 0.00263

Gnomad4 OTH AF: 0.00286

Alfa AF: 0.000598 Hom.: 9188

TwinsUK AF: 0.00324 AC: 12

ALSPAC AF: 0.00234 AC: 9

ExAC AF: 0.00205 AC: 247

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:34 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency Pathogenic:24 Other:1

May 22, 2022

3billion, Medical Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.220%). However, frequency data for this variant in the general population cannot be distinguished from that of the (CYP21P) pseudogene, and are therefore uninformative in assessment of variant pathogenicity. In silico tools predict the variant to alter splicing and produce an abnormal transcript (SpliceAI: 0.75). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least 2 similarly affected unrelated individuals (PMID: 24904866, 25630015, 26206692). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Jul 21, 2021

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was identified as compound heterozygous with NM_000500.9:c.?_939+50del. -

Jan 08, 2020

New York Genome Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 01, 2003

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Jan 15, 2019

Illumina Laboratory Services, Illumina

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CYP21A2 c.293-13C>G variant is an intronic variant. Across a selection of the available literature, this variant has been reported in a homozygous state in at least 13 individuals with congenital adrenal hyperplasia due to 21-hydroxylase deficiency and in a compound heterozygous state in at least 48 patients (Speiser et al. 1992; Yoo et al. 2013; Hong et al. 2015; Mohamed et al. 2015). In several families, presumably unaffected parents were identified to be heterozygous carriers of the c.293-13C>G variant. This variant is reported at a frequency of 0.003896 in the Ashkenazi Jewish population from the Genome Aggregation Database. Functional studies in COS-7 cells showed absent CYP21A2 activity for this variant (Higashi et al. 1988). Further, the c.293-13C>G variant was shown to result in abnormal splicing, producing a frameshift which results in premature truncation of the protein. Based on the collective evidence, the c.293-13C>G variant is pathogenic for congenital adrenal hyperplasia due to 21-hydroxylase deficiency. -

-

Genomics England Pilot Project, Genomics England

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Lifecell International Pvt. Ltd

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant present in Intron 2 of the CYP21A2 gene c.293-13A/C>G (NM_000500.7). This variant was observed in a proband with increased level of 17-OHP enzyme (>303.7nmol/L) which was screened for advanced newborn screening with confirmatory genetic reflex testing at lifecell diagnostics. This variant has a minor allele frequency of 0.1988% and 0.2261% in 1000 genomes and gnomAD Exomes databases respectively. This variant is characterized by the substitution of A or C nucleotide at 13 bp before the end of intron 2 to G, and activates a cryptic upstream 3' splice acceptor site and causing aberrant splicing (New et al., 2013)This variant has been reported for 21-hydroxylase deficiency (Billerbeck AE et al., 2002 PMID: 12213891, Higashi et al., 1988 PMID: 2845408, Speiser et al., 1992 PMID: 1644925). -

-

GenomeConnect, ClinGen

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

Variant interpreted as Pathogenic and reported on 11-12-2018 by Lab or GTR ID 500068. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -

Oct 26, 2017

Institute of Human Genetics Munich, Klinikum Rechts Der Isar, TU München

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 03, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 04, 2024

Al Jalila Children’s Genomics Center, Al Jalila Childrens Speciality Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

PM3_VeryStrong, PS3 -

Aug 29, 2013

GeneReviews

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Dec 20, 2019

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NM_000500.7(CYP21A2):c.293-13C>G is classified as pathogenic in the context of congenital adrenal hyperplasia and is associated with the classic form of the disease. Sources cited for classification include the following: PMID 1644925 and 2845408. Classification of NM_000500.7(CYP21A2):c.293-13C>G is based on the following criteria: This is a well-established pathogenic variant in the literature that has been observed more frequently in patients with clinical diagnoses than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -

May 28, 2019

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 29, 2013

GeneReviews

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Mar 15, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CYP21A2 c.293-13C>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Two predict the variant weakens a 3' acceptor site, and one predicts the variant abolishes a 3' acceptor site. At least one publication reports experimental evidence that this variant affects mRNA splicing (e.g., Higashi_1988). The variant allele was found at a frequency of 0.0023 in 221616 control chromosomes (gnomAD v2.1, Exomes cohort), however, this allele frequency data may be unreliable due to reported possible pseudogene overlap. c.293-13C>G has been reported in the literature in numerous homozygous and compound heterozygous individuals affected with Congenital Adrenal Hyperplasia/Salt Wasting, presenting with salt-wasting, simple virilizing, and non-classical phenotypes (e.g., Wilson_2007, New_2013). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, finding that COS cells transfected with the variant displayed undetectable steroid 21-hydroxylase activity (e.g., Higashi_1988). Nineteen ClinVar submitters (evaluation after 2014) have cited the variant, with eighteen submitters classifying the variant as pathogenic and only one submitter classifying the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as pathogenic. -

-

Medical Laboratory Center, Huzhou Maternal and Child Health Hospital

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Dec 28, 2023

Provincial Medical Genetics Program of British Columbia, University of British Columbia

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 01, 2024

Laboratory of Medical Genetics, National & Kapodistrian University of Athens

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Jul 16, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with congenital adrenal hyperplasia, due to 21-hydroxylase deficiency (MIM#201910) and nonclassic type hyperandrogenism, due to 21-hydroxylase deficiency (MIM#201910). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0210 - Splice site variant proven to affect splicing of the transcript with a known effect on protein sequence. RNA studies have shown that this variant causes aberrant splicing which is predicted to cause a frameshift and create a premature termination codon (PMID: 2845408). (SP) 0252 - This variant is homozygous. (I) 0304 - Variant is present in gnomAD (v3) <0.01 for a recessive condition (325 heterozygotes, 1 homozygote). (SP) 0508 - In silico predictions for abnormal splicing are conflicting. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This has been classified as pathogenic by mulitple clinical laboratories in ClinVar and is very well reported in both compound heterozygous and homozygous states in individuals with congenital adrenal hypoplasia (PMIDs: 35355919, 31586465, 32289882). (SP) 1209 - This variant has been shown to be both maternally and paternally inherited (biallelic) (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

-

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PM3_VeryStrong+PS3 -

Apr 04, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 27, 2020

Breakthrough Genomics, Breakthrough Genomics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is a well-established pathogenic variant and reported as the most frequent nondeletional mutation found in patients with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency [PMID: 20301350, 1644925, 2845408, 25041270]. The variant has been reported to cause aberrant splicing of intron 2 resulting in a shift in the translational reading frame [PMID: 20301350, 2845408, 1869518]. -

Nov 24, 2023

Zotz-Klimas Genetics Lab, MVZ Zotz Klimas

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not provided Pathogenic:7

Jul 24, 2015

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 28, 2023

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CYP21A2 c.293-13C>G variant (also known as IVS2-13A/C>G or Intron 2G) has been reported in the published literature to disrupt normal splicing of the CYP21A2 mRNA (PMID: 2845408 (1988)) and is usually associated with classic CAH, either simple virilizing or salt wasting (PMIDs: 1644925 (1992), 12213891 (2002), 12788880 (2003), 12915679 (2003), 18381579 (2008), 31586465 (2020), 32289882 (2020), 32959514 (2020)). The frequency of this variant in the general population, 0.0037 (36/9714 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is consistent with pathogenicity. Based on the available information, this variant is classified as pathogenic. -

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 2 of the CYP21A2 gene. It does not directly change the encoded amino acid sequence of the CYP21A2 protein. The frequency data for this variant in the population databases (gnomAD) is considered unreliable due to the presence of homologous sequence, such as pseudogenes or paralogs, in the genome. This variant has been observed in individual(s) with classic salt-wasting, simple virilizing, and non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (PMID: 20080860, 30995443). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as IVS2-13A/C>G, I2G, c.293-13A/C>G, In2G. ClinVar contains an entry for this variant (Variation ID: 12155). 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. -

Feb 05, 2021

Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PS3, PS4 -

Mar 20, 2023

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 07, 2024

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is located in a genomic region of low or unreliable sequencing quality, and therefore estimations of its population frequency are uninformative in assessment of variant pathogenicity. (http://gnomad.broadinstitute.org) In multiple individuals, this variant has been seen in trans with other recessive pathogenic variants in CYP21A2, suggesting this variant is also pathogenic. In some published literature, this variant is referred to by nucleotide 655 or 656, and also called the intron 2 G, I2G, or I2 splice variant. Assessment of experimental evidence suggests this variant results in abnormal protein function. (PMID: 2845408) -

Aug 18, 2022

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases Pathogenic:1

Apr 22, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

See cases Pathogenic:1

Oct 19, 2018

Institute of Human Genetics, University Hospital Muenster

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ACMG categories: PS3,PM2,PM3,PP1,PP4,PP5 -

Congenital adrenal hyperplasia Pathogenic:1

Jun 18, 2020

Human Genome Sequencing Center Clinical Lab, Baylor College of Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This c.293-13C>G variant is among the most frequent pathogenic variants in patients with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency [OMIM 613815.0006]. It causes premature splicing of the intron and a shift in the translational reading frame [PMID 15146390, 25525159]. This variant has been detected in 206 heterozygous and 2 homozygous individuals from the ExAC population database (http://exac.broadinstitute.org/variant/16-3293310-A-G) and in affected patients at the homozygous state in our internal database. This variant is classified as pathogenic. Homozygosity for this variant is also considered medically actionable. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.54	T
BayesDel_noAF	Benign	-0.56
CADD	Benign	1.7
DANN	Benign	0.38
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.0080	N
LIST_S2	Benign	0.23	T
MetaRNN	Benign	0.0066	T
MetaSVM	Benign	-1.0	T
PROVEAN	Benign	0.10	N
REVEL	Benign	0.044
Sift	Benign	1.0	T
Sift4G	Pathogenic	0.0	D
MVP		0.25
ClinPred		0.0033	T
GERP RS		-0.59

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.75		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.75		Position offset: 13

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

Publications

LitVar

Other links and lift over

dbSNP: rs6467; hg19: chr6-32006858;