rs768832921

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001918.5(DBT):c.75_76del(p.Cys26TrpfsTer2) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000508 in 1,613,208 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T25T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000052 ( 0 hom. )

Consequence

DBT
NM_001918.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 1.55

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:

(HGNC:):

links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 87 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-100240859-CAT-C is Pathogenic according to our data. Variant chr1-100240859-CAT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 11950.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DBT	NM_001918.5 linkuse as main transcript	c.75_76del	p.Cys26TrpfsTer2	frameshift_variant	2/11	ENST00000370132.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DBT	ENST00000370132.8 linkuse as main transcript	c.75_76del	p.Cys26TrpfsTer2	frameshift_variant	2/11	1	NM_001918.5	P1
	ENST00000648283.1 linkuse as main transcript	n.62-8604_62-8603del		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152170

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000576

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000677

AC:

AN:

251058

Hom.:

AF XY:

0.0000590

AC XY:

AN XY:

135698

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.000397

Gnomad EAS exome

AF:

0.000109

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000793

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000520

AC:

AN:

1461038

Hom.:

AF XY:

0.0000454

AC XY:

AN XY:

726852

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.000498

Gnomad4 EAS exome

AF:

0.0000758

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000495

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152170

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74342

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.000576

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000142

Hom.:

Bravo

AF:

0.0000453

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Maple syrup urine disease

Pathogenic:8

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 30, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Aug 11, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Dec 24, 2019	NM_001918.3(DBT):c.75_76delAT(C26Wfs2) is classified as pathogenic in the context of maple syrup urine disease type II. Sources cited for classification include the following: PMID 8430702. Classification of NM_001918.3(DBT):c.75_76delAT(C26Wfs2) is based on the following criteria: The variant causes a premature termination codon that is expected to be targeted by nonsense-mediated mRNA decay and is reported in individuals with the relevant phenotype. Please note: this variant was assessed in the context of healthy population screening. -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Aug 16, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Research Center, Shahid Beheshti University of Medical Sciences	Dec 18, 2017	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Department Of Genetics, Sultan Qaboos University Hospital, Sultan Qaboos University	Dec 30, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 08, 2023	This sequence change creates a premature translational stop signal (p.Cys26Trpfs*2) in the DBT gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in DBT are known to be pathogenic (PMID: 16579849, 16786533). This variant is present in population databases (rs768832921, gnomAD 0.03%). This premature translational stop signal has been observed in individuals with maple syrup urine disease (PMID: 8430702, 14517957, 16468966, 20639189, 28417071). ClinVar contains an entry for this variant (Variation ID: 11950). For these reasons, this variant has been classified as Pathogenic. -

Maple syrup urine disease type 2

Pathogenic:3

Pathogenic, no assertion criteria provided	literature only	OMIM	Feb 01, 1993	- -
Pathogenic, criteria provided, single submitter	clinical testing	Knight Diagnostic Laboratories, Oregon Health and Sciences University	Mar 18, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 23, 2015	- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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