rs775808731

Positions:

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_001918.5(DBT):c.872G>T(p.Arg291Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,896 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R291Q) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

DBT
NM_001918.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3

Conservation

PhyloP100: 7.57

Variant links:

Genes affected

DBT (HGNC:2698): (dihydrolipoamide branched chain transacylase E2) The branched-chain alpha-keto acid dehydrogenase complex (BCKD) is an inner-mitochondrial enzyme complex involved in the breakdown of the branched-chain amino acids isoleucine, leucine, and valine. The BCKD complex is thought to be composed of a core of 24 transacylase (E2) subunits, and associated decarboxylase (E1), dehydrogenase (E3), and regulatory subunits. This gene encodes the transacylase (E2) subunit. Mutations in this gene result in maple syrup urine disease, type 2. Alternatively spliced transcript variants have been described, but their biological validity has not been determined. [provided by RefSeq, Jul 2008]

DBT links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-100214884-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2064599.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DBT	NM_001918.5 linkuse as main transcript	c.872G>T	p.Arg291Leu	missense_variant	7/11	ENST00000370132.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris
DBT	ENST00000370132.8 linkuse as main transcript	c.872G>T	p.Arg291Leu	missense_variant	7/11	1	NM_001918.5	P1
DBT	ENST00000370131.3 linkuse as main transcript	c.872G>T	p.Arg291Leu	missense_variant	7/8	1
DBT	ENST00000681617.1 linkuse as main transcript	c.872G>T	p.Arg291Leu	missense_variant	7/12
DBT	ENST00000681780.1 linkuse as main transcript	c.329G>T	p.Arg110Leu	missense_variant	8/12

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

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:

251456

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135904

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

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

AF:

0.00000205

AC:

AN:

1461756

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727192

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74300

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000262

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:

0.0000416

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Maple syrup urine disease

Pathogenic:1Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 21, 2023	This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 291 of the DBT protein (p.Arg291Leu). This variant is present in population databases (no rsID available, gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of maple syrup urine disease (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 457147). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt DBT protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Apr 10, 2018	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Nov 15, 2023

Variant summary: DBT c.872G>T (p.Arg291Leu) results in a non-conservative amino acid change located in the 2-oxoacid dehydrogenase acyltransferase, catalytic domain of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251456 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.872G>T in individuals affected with Maple Syrup Urine Disease and no experimental evidence demonstrating its impact on protein function have been reported. One clinical lab via ClinVar has reported this variant to be observed in trans with another DBT variant in an individual with biochemical findings that are highly specific for Maple Syrup Urine Disease (Invitae). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014, and classified it as pathogenic (n=1) or uncertain significance (n=2). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.84

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.22

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.88

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.97

.;D

M_CAP

Uncertain

0.095

MetaRNN

Pathogenic

0.98

D;D

MetaSVM

Uncertain

-0.17

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.50

PROVEAN

Pathogenic

-6.0

D;D

REVEL

Pathogenic

0.74

Sift

Uncertain

0.0020

D;D

Sift4G

Uncertain

0.0020

D;D

Vest4

0.91

MutPred

0.89

Gain of ubiquitination at K295 (P = 0.0606);Gain of ubiquitination at K295 (P = 0.0606);

MVP

0.83

MPC

1.1

ClinPred

1.0

GERP RS

5.4

gMVP

0.95

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

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over