Genetic Variant CYP2A6:p.Ile300Asn (chr19-40846030-A-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_000762.6(CYP2A6):c.899T>A(p.Ile300Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000132 in 151,136 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 31)

Consequence

CYP2A6
NM_000762.6 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.471

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 links:

ENSG00000268797 (HGNC:):

ENSG00000268797 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM1

In a mutagenesis_site Increases phenacetin O-deethylation activity 3 fold. Increases phenacetin O-deethylation activity 8 fold; when associated with A-301. Increases phenacetin O-deethylation activity 10 fold; when associated with S-208 and A-301. Increases phenacetin O-deethylation activity 12 fold; when associated with A-301 and G-369. Increases phenacetin O-deethylation activity 38 fold; when associated with S-208; A-301 and G-369. (size 0) in uniprot entity CP2A6_HUMAN

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.895

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP2A6	NM_000762.6 link	c.899T>A	p.Ile300Asn	missense_variant	Exon 6 of 9	ENST00000301141.10	NP_000753.3	P11509

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP2A6	ENST00000301141.10 link	c.899T>A	p.Ile300Asn	missense_variant	Exon 6 of 9	1	NM_000762.6	ENSP00000301141.4		P11509
ENSG00000268797	ENST00000601627.1 link	n.117+44615A>T		intron_variant	Intron 1 of 3	3		ENSP00000469533.1		M0QY20

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151136

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000488

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:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251126

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135734

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.0000132

AC:

AN:

151136

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

73728

show subpopulations

Gnomad4 AFR

AF:

0.0000488

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.58

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.36

CADD

Benign

DANN

Uncertain

0.99

Eigen

Benign

-0.18

Eigen_PC

Benign

-0.36

FATHMM_MKL

Benign

0.36

LIST_S2

Benign

0.83

M_CAP

Benign

0.031

MetaRNN

Pathogenic

0.90

MetaSVM

Benign

-0.63

PrimateAI

Uncertain

0.53

PROVEAN

Benign

-2.2

REVEL

Uncertain

0.36

Sift

Benign

0.040

Sift4G

Benign

0.063

Vest4

0.56

MutPred

0.82

Gain of disorder (P = 0.034);

MVP

0.77

MPC

0.51

ClinPred

0.36

GERP RS

2.4

gMVP

0.47

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

LitVar

Other links and lift over