chr6-32038254-C-A

Variant names:

• chr6-32038254-C-A
• rs1775966542
• NM_000500.9:c.-169C>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000500.9(CYP21A2):​c.-169C>A variant causes a upstream gene change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000155 in 1,294,328 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000015 (0 hom.)
• Consequence: CYP21A2 NM_000500.9 upstream_gene
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.223
• Publications: 0 publications found

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: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Myriad Women’s Health
• 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

ACMG classification

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=-0.64).

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP21A2	NM_000500.9	MANE Select	c.-169C>A		upstream_gene	N/A	NP_000491.4
	CYP21A2	NM_001128590.4		c.-169C>A		upstream_gene	N/A	NP_001122062.3	P08686-2
	CYP21A2	NM_001368143.2		c.-593C>A		upstream_gene	N/A	NP_001355072.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYP21A2	ENST00000644719.2	MANE Select	c.-169C>A		upstream_gene	N/A	ENSP00000496625.1	P08686-1
	CYP21A2	ENST00000960600.1		c.-169C>A		upstream_gene	N/A	ENSP00000630659.1
	CYP21A2	ENST00000960597.1		c.-169C>A		upstream_gene	N/A	ENSP00000630656.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000155 AC: 2 AN: 1294328 Hom.: 0 Cov.: 24 AF XY: 0.00000157 AC XY: 1 AN XY: 636310

⚠️ 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: 29370

American (AMR) AF: 0.00 AC: 0 AN: 32038

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 23034

East Asian (EAS) AF: 0.00 AC: 0 AN: 34876

South Asian (SAS) AF: 0.00 AC: 0 AN: 74154

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33310

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3842

European-Non Finnish (NFE) AF: 0.00000198 AC: 2 AN: 1009332

Other (OTH) AF: 0.00 AC: 0 AN: 54372

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.64
CADD	Benign	7.4
DANN	Benign	0.73
PhyloP100		0.22
PromoterAI		-0.071	Neutral

Splicing

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

Other links and lift over

dbSNP: rs1775966542; hg19: chr6-32006031;