Genetic Variant CYP21A2:c.652-4G>T (chr6-32039745-G-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000500.9(CYP21A2):c.652-4G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000187 in 1,608,108 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

CYP21A2
NM_000500.9 splice_region, intron

Scores

Splicing: ADA: 0.00003158

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.227

Publications

0 publications found

Variant links:

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]

CYP21A2 Gene-Disease associations (from GenCC):

classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Myriad Women’s Health, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine
classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, salt wasting form
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, simple virilizing form
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

CYP21A2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.65).

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
CYP21A2	NM_000500.9 link	c.652-4G>T	splice_region_variant, intron_variant	Intron 5 of 9	ENST00000644719.2	NP_000491.4	P08686Q16874Q08AG9
CYP21A2	NM_001128590.4 link	c.562-4G>T	splice_region_variant, intron_variant	Intron 4 of 8		NP_001122062.3	P08686Q08AG9
CYP21A2	NM_001368143.2 link	c.247-4G>T	splice_region_variant, intron_variant	Intron 5 of 9		NP_001355072.1
CYP21A2	NM_001368144.2 link	c.247-4G>T	splice_region_variant, intron_variant	Intron 4 of 8		NP_001355073.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP21A2	ENST00000644719.2 link	c.652-4G>T		splice_region_variant, intron_variant	Intron 5 of 9		NM_000500.9	ENSP00000496625.1		Q16874

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151984

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000416

AC:

AN:

240450

AF XY:

0.00

show subpopulations

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:

0.00000923

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1456124

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

723764

show subpopulations

African (AFR)

AF:

0.0000301

AC:

AN:

33276

American (AMR)

AF:

0.00

AC:

AN:

44144

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26016

East Asian (EAS)

AF:

0.00

AC:

AN:

39376

South Asian (SAS)

AF:

0.00

AC:

AN:

84986

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52976

Middle Eastern (MID)

AF:

0.000174

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1109450

Other (OTH)

AF:

0.00

AC:

AN:

60140

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151984

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74210

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41374

American (AMR)

AF:

0.0000655

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5164

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10588

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67998

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000165

Hom.:

Bravo

AF:

0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.65

CADD

Benign

2.8

(source)

DANN

Benign

0.55

PhyloP100

-0.23

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000032

dbscSNV1_RF

Benign

0.0020

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over