chr19-41410638-AC-A
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000709.4(BCKDHA):c.117delC(p.Arg40GlyfsTer23) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,326 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. P39P) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000709.4 frameshift
Scores
Clinical Significance
Conservation
Publications
- maple syrup urine diseaseInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
- maple syrup urine disease type 1AInheritance: AR Classification: DEFINITIVE Submitted by: G2P, Myriad Women’s Health, ClinGen
- classic maple syrup urine diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- intermediate maple syrup urine diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- intermittent maple syrup urine diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- thiamine-responsive maple syrup urine diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 18 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| BCKDHA | NM_000709.4 | c.117delC | p.Arg40GlyfsTer23 | frameshift_variant | Exon 2 of 9 | ENST00000269980.7 | NP_000700.1 | |
| BCKDHA | NM_001164783.2 | c.117delC | p.Arg40GlyfsTer23 | frameshift_variant | Exon 2 of 9 | NP_001158255.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| BCKDHA | ENST00000269980.7 | c.117delC | p.Arg40GlyfsTer23 | frameshift_variant | Exon 2 of 9 | 1 | NM_000709.4 | ENSP00000269980.2 | ||
| ENSG00000255730 | ENST00000540732.3 | c.219delC | p.Arg74GlyfsTer23 | frameshift_variant | Exon 3 of 10 | 2 | ENSP00000443246.1 |
Frequencies
GnomAD3 genomes AF: 0.0000792 AC: 12AN: 151564Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 250846 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000116 AC: 17AN: 1461762Hom.: 0 Cov.: 32 AF XY: 0.0000110 AC XY: 8AN XY: 727180 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000792 AC: 12AN: 151564Hom.: 0 Cov.: 31 AF XY: 0.0000811 AC XY: 6AN XY: 73946 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Maple syrup urine disease Pathogenic:6
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This is a frame-shift variant in the BCKDHA gene, where loss of function is a known mechanism of disease. This variant results in a truncated protein by creating a premature stop codon. It has been published in the literature associated with individuals with MSUD (PMID: 16786533, PMID: 25333063, PMID: 26232051). -
This sequence change creates a premature translational stop signal (p.Arg40Glyfs*23) in the BCKDHA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BCKDHA are known to be pathogenic (PMID: 16786533, 22593002). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individuals with maple syrup urine disease (PMID: 16786533, 25333063). ClinVar contains an entry for this variant (Variation ID: 93342). For these reasons, this variant has been classified as Pathogenic. -
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Maple syrup urine disease type 1A Pathogenic:4
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
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Variant summary: BCKDHA c.117delC (p.Arg40GlyfsX23) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 1.2e-05 in 250946 control chromosomes. c.117delC has been reported in the literature in multiple individuals affected with Maple Syrup Urine Disease Type 1A (example, Couce_2015, Fernandez_Guerra_2014, Quental_2008, Strauss_2006). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (example, Fernandez_Guerra_2014). The most pronounced variant effect resulted in a loss of detectable levels of protein subunit E1alpha that is encoded by BCKDHA in human dermal fibroblasts from classic MSUD patients. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
not provided Pathogenic:2
Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 26232051, 31980395, 16786533, 25333063, 31589614, 18378174) -
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at