chr6-80106713-C-CT

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_183050.4(BCKDHB):​c.21dup​(p.Ala8CysfsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000714 in 1,399,818 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. A7A) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 7.1e-7 ( 0 hom. )

Consequence

BCKDHB
NM_183050.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: -1.13
Variant links:
Genes affected
BCKDHB (HGNC:987): (branched chain keto acid dehydrogenase E1 subunit beta) This gene encodes the E1 beta subunit of branched-chain keto acid dehydrogenase, which is a multienzyme complex associated with the inner membrane of mitochondria. This enzyme complex functions in the catabolism of branched-chain amino acids. Mutations in this gene have been associated with maple syrup urine disease (MSUD), type 1B, a disease characterized by a maple syrup odor to the urine in addition to mental and physical retardation and feeding problems. Alternative splicing at this locus results in multiple transcript variants. [provided by RefSeq, Jan 2016]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 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 131 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 6-80106713-C-CT is Pathogenic according to our data. Variant chr6-80106713-C-CT is described in ClinVar as [Pathogenic]. Clinvar id is 1452370.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
BCKDHBNM_183050.4 linkuse as main transcriptc.21dup p.Ala8CysfsTer13 frameshift_variant 1/10 ENST00000320393.9

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
BCKDHBENST00000320393.9 linkuse as main transcriptc.21dup p.Ala8CysfsTer13 frameshift_variant 1/101 NM_183050.4 P1P21953-1
BCKDHBENST00000356489.9 linkuse as main transcriptc.21dup p.Ala8CysfsTer13 frameshift_variant 1/111 P1P21953-1
BCKDHBENST00000369760.8 linkuse as main transcriptc.21dup p.Ala8CysfsTer13 frameshift_variant 1/63 P21953-2

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
7.14e-7
AC:
1
AN:
1399818
Hom.:
0
Cov.:
32
AF XY:
0.00000145
AC XY:
1
AN XY:
690904
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
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:
9.25e-7
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Maple syrup urine disease Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpJul 03, 2021For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals affected with BCKDHB-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This sequence change creates a premature translational stop signal (p.Ala8Cysfs*13) in the BCKDHB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BCKDHB are known to be pathogenic (PMID: 16786533, 22593002). -

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr6-80816430; API