19-40991386-T-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_000767.5(CYP2B6):c.81T>A(p.His27Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 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. H27L) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

CYP2B6
NM_000767.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -2.00

Publications

0 publications found

Variant links:

Genes affected

CYP2B6 (HGNC:2615): (cytochrome P450 family 2 subfamily B member 6) This gene, CYP2B6, 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 metabolize some xenobiotics, such as the anti-cancer drugs cyclophosphamide and ifosphamide. Transcript variants for this gene have been described; however, it has not been resolved whether these transcripts are in fact produced by this gene or by a closely related pseudogene, CYP2B7. Both the gene and the pseudogene are located in the middle of a CYP2A pseudogene found in a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q. [provided by RefSeq, Jul 2008]

CYP2B6 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.14450726).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP2B6	NM_000767.5 link	c.81T>A	p.His27Gln	missense_variant	Exon 1 of 9	ENST00000324071.10	NP_000758.1	P20813-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP2B6	ENST00000324071.10 link	c.81T>A	p.His27Gln	missense_variant	Exon 1 of 9	1	NM_000767.5	ENSP00000324648.2		P20813-1
CYP2B6	ENST00000598834.2 link	n.-19T>A		upstream_gene_variant		5		ENSP00000496294.1		A0A2R8YFA4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461870

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727238

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33470

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jun 07, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.81T>A (p.H27Q) alteration is located in exon 1 (coding exon 1) of the CYP2B6 gene. This alteration results from a T to A substitution at nucleotide position 81, causing the histidine (H) at amino acid position 27 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.49

CADD

Benign

0.28

(source)

DANN

Benign

0.67

DEOGEN2

Benign

0.0014

T;T

Eigen

Benign

-0.91

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.011

LIST_S2

Benign

0.14

.;T

M_CAP

Benign

0.0040

MetaRNN

Benign

0.14

T;T

MetaSVM

Benign

-0.96

MutationAssessor

Benign

0.81

L;L

PhyloP100

-2.0

PrimateAI

Benign

0.45

PROVEAN

Benign

-0.92

.;N

REVEL

Benign

0.21

Sift

Benign

0.093

.;T

Sift4G

Benign

0.31

.;T

Polyphen

0.97

D;D

Vest4

0.12

MutPred

0.17

Gain of helix (P = 0.0854);Gain of helix (P = 0.0854);

MVP

0.63

MPC

0.21

ClinPred

0.23

GERP RS

-3.4

PromoterAI

0.020

Neutral

(source)

Varity_R

0.054

gMVP

0.24

Mutation Taster

=99/1

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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19-40991386-T-A

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over