Genetic Variant NM_000500.9:c.719T>C (chr6-32039816-T-C) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 5P and 2B. PM1PM2PP2BP4_Moderate

The NM_000500.9(CYP21A2):c.719T>C(p.Met240Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M240K) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

CYP21A2
NM_000500.9 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.343

Publications

40 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: Uncertain_significance. The variant received 3 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_000500.9

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 52 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Trascript score misZ: 1.8021 (below the threshold of 3.09). GenCC associations: The gene is linked to classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, simple virilizing form, classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, salt wasting form.

BP4

Computational evidence support a benign effect (MetaRNN=0.08986205).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000500.9. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CYP21A2	NM_000500.9	MANE Select	c.719T>C	p.Met240Thr	missense	Exon 6 of 10	NP_000491.4
CYP21A2	NM_001128590.4		c.629T>C	p.Met210Thr	missense	Exon 5 of 9	NP_001122062.3
CYP21A2	NM_001368143.2		c.314T>C	p.Met105Thr	missense	Exon 6 of 10	NP_001355072.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CYP21A2	ENST00000644719.2	MANE Select	c.719T>C	p.Met240Thr	missense	Exon 6 of 10	ENSP00000496625.1
CYP21A2	ENST00000435122.3	TSL:2	c.629T>C	p.Met210Thr	missense	Exon 5 of 9	ENSP00000415043.2
CYP21A2	ENST00000462278.1	TSL:4	n.408T>C		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.000478

GnomAD2 exomes

AF:

0.00

AC:

AN:

250242

AF XY:

0.00

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461664

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727092

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86216

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111882

Other (OTH)

AF:

0.0000166

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

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:

0.0000197

AC:

AN:

152186

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74354

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41438

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.000478

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.408

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 12, 2024

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: CYP21A2 c.719T>C (p.Met240Thr) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The frequency data for this variant in gnomAD is considered unreliable, as metrics indicate poor data quality at this position. To our knowledge, no occurrence of c.719T>C in individuals affected with Congenital Adrenal Hyperplasia and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. p.Met240Lys was classified as likely benign internally. Based on the evidence outlined above, the variant was classified as uncertain significance.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.14

BayesDel_noAF

Benign

-0.44

CADD

Benign

(source)

DANN

Benign

0.87

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.068

M_CAP

Benign

0.044

MetaRNN

Benign

0.090

MetaSVM

Benign

-1.0

PhyloP100

0.34

PrimateAI

Benign

0.31

PROVEAN

Benign

0.030

REVEL

Benign

0.13

Sift

Benign

0.092

Sift4G

Benign

0.47

Polyphen

0.0

Vest4

0.091

MutPred

0.56

Loss of MoRF binding (P = 0.0908)

MVP

0.76

MPC

0.53

ClinPred

0.031

GERP RS

1.6

gMVP

0.35

Mutation Taster

=93/7

polymorphism

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over