chr19-41422370-G-C
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_000709.4(BCKDHA):c.853G>C(p.Ala285Pro) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000551 in 1,614,022 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A285S) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000709.4 missense, splice_region
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.853G>C | p.Ala285Pro | missense_variant, splice_region_variant | Exon 6 of 9 | ENST00000269980.7 | NP_000700.1 | |
| BCKDHA | NM_001164783.2 | c.853G>C | p.Ala285Pro | missense_variant, splice_region_variant | Exon 6 of 9 | NP_001158255.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| BCKDHA | ENST00000269980.7 | c.853G>C | p.Ala285Pro | missense_variant, splice_region_variant | Exon 6 of 9 | 1 | NM_000709.4 | ENSP00000269980.2 | ||
| ENSG00000255730 | ENST00000540732.3 | c.955G>C | p.Ala319Pro | missense_variant, splice_region_variant | Exon 7 of 10 | 2 | ENSP00000443246.1 |
Frequencies
GnomAD3 genomes AF: 0.0000788 AC: 12AN: 152188Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000318 AC: 8AN: 251378 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000527 AC: 77AN: 1461834Hom.: 0 Cov.: 33 AF XY: 0.0000495 AC XY: 36AN XY: 727216 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000788 AC: 12AN: 152188Hom.: 0 Cov.: 32 AF XY: 0.0000807 AC XY: 6AN XY: 74346 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Maple syrup urine disease Pathogenic:4
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This is a null variant in a gene where the loss of function is a known disease mechanism. It is located within exon 6 and generates a change from the amino acid Alanine to a Proline in position 285. It is present in population databases in low frequency (GnomAD exomes: 0.000032, ExAc: 0.000033). This variant has been published in the literature associated with individuals with MSUD (PMID: 9582350, PMID: 26232051). It was found in a compound heterozygous state with a pathogenic variant in a patient with MSUD phenotype. -
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This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 285 of the BCKDHA protein (p.Ala285Pro). This variant also falls at the last nucleotide of exon 6, which is part of the consensus splice site for this exon. This variant is present in population databases (rs398123508, gnomAD 0.008%). This missense change has been observed in individual(s) with maple syrup urine disease (PMID: 9582350, 14517957, 26232051). This variant is also known as A240P. ClinVar contains an entry for this variant (Variation ID: 93375). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects BCKDHA function (PMID: 9582350). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Maple syrup urine disease type 1A Pathogenic:3
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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. -
not provided Pathogenic:2
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at