Genetic Variant CYP2A6:p.Met489Lys (chr19-40843815-A-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000762.6(CYP2A6):c.1466T>A(p.Met489Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M489T) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 30)

Exomes 𝑓: 0.000015 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CYP2A6
NM_000762.6 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 5.45

Publications

2 publications found

Variant links:

Genes affected

CYP2A6 (HGNC:2610): (cytochrome P450 family 2 subfamily A member 6) This gene, CYP2A6, 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 its expression is induced by phenobarbital. The enzyme is known to hydroxylate coumarin, and also metabolizes nicotine, aflatoxin B1, nitrosamines, and some pharmaceuticals. Individuals with certain allelic variants are said to have a poor metabolizer phenotype, meaning they do not efficiently metabolize coumarin or nicotine. This gene is part of a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q. The gene was formerly referred to as CYP2A3; however, it has been renamed CYP2A6. [provided by RefSeq, Jul 2008]

CYP2A6 Gene-Disease associations (from GenCC):

coumarin resistance
Inheritance: Unknown Classification: NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae)
nicotine dependence
Inheritance: Unknown Classification: NO_KNOWN Submitted by: Labcorp Genetics (formerly Invitae)

CYP2A6 links:

ENSG00000268797 (HGNC:):

ENSG00000268797 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP2A6	NM_000762.6 link	c.1466T>A	p.Met489Lys	missense_variant	Exon 9 of 9	ENST00000301141.10	NP_000753.3	P11509

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
CYP2A6	ENST00000301141.10 link	c.1466T>A	p.Met489Lys	missense_variant	Exon 9 of 9	1	NM_000762.6	ENSP00000301141.4	P11509
ENSG00000268797	ENST00000601627.1 link	n.117+42400A>T		intron_variant	Intron 1 of 3	3		ENSP00000469533.1	M0QY20
CYP2A6	ENST00000599960.1 link	n.385T>A		non_coding_transcript_exon_variant	Exon 2 of 2	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000400

AC:

AN:

250236

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:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.0000151

AC:

AN:

1460178

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

726400

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33436

American (AMR)

AF:

0.00

AC:

AN:

44688

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

38556

South Asian (SAS)

AF:

0.00

AC:

AN:

86158

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.0000198

AC:

AN:

1111764

Other (OTH)

AF:

0.00

AC:

AN:

60294

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 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: 0.245

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ExAC

AF:

0.0000165

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.87

BayesDel_addAF

Benign

-0.061

BayesDel_noAF

Benign

-0.33

CADD

Uncertain

(source)

DANN

Benign

0.97

Eigen

Benign

-0.16

Eigen_PC

Benign

-0.16

FATHMM_MKL

Benign

0.74

LIST_S2

Benign

0.53

M_CAP

Benign

0.0052

MetaRNN

Uncertain

0.63

MetaSVM

Benign

-1.1

PhyloP100

5.4

PrimateAI

Uncertain

0.54

PROVEAN

Uncertain

-4.2

REVEL

Benign

0.14

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Vest4

0.28

MutPred

0.85

Gain of MoRF binding (P = 0.0152);

MVP

0.28

MPC

2.6

ClinPred

0.96

GERP RS

3.0

gMVP

0.82

Mutation Taster

=76/24

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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chr19-40843815-A-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

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