chr19-41422665-G-C

Variant names:

• chr19-41422665-G-C
• rs200137189
• NM_000709.4:c.890G>C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000709.4(BCKDHA):​c.890G>C​(p.Arg297Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,126 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R297C) has been classified as Likely pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: BCKDHA NM_000709.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.30
• Publications: 2 publications found

Genes affected

BCKDHA (HGNC:986): (branched chain keto acid dehydrogenase E1 subunit alpha) The branched-chain alpha-keto acid (BCAA) dehydrogenase (BCKD) complex is an innter mitochondrial enzyme complex that catalyzes the second major step in the catabolism of the branched-chain amino acids leucine, isoleucine, and valine. The BCKD complex consists of three catalytic components: a heterotetrameric (alpha2-beta2) branched-chain alpha-keto acid decarboxylase (E1), a dihydrolipoyl transacylase (E2), and a dihydrolipoamide dehydrogenase (E3). This gene encodes the alpha subunit of the decarboxylase (E1) component. Mutations in this gene result in maple syrup urine disease, type IA. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Sep 2009]

BCKDHA Gene-Disease associations (from GenCC):

• maple syrup urine disease

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• maple syrup urine disease type 1A

  Inheritance: AR Classification: DEFINITIVE Submitted by: G2P, Myriad Women’s Health, ClinGen
• classic maple syrup urine disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• intermediate maple syrup urine disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• intermittent maple syrup urine disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• thiamine-responsive maple syrup urine disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000255730 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000709.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-41422664-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 555477.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.976

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000709.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BCKDHA	NM_000709.4	MANE Select	c.890G>C	p.Arg297Pro	missense	Exon 7 of 9	NP_000700.1
	BCKDHA	NM_001164783.2		c.887G>C	p.Arg296Pro	missense	Exon 7 of 9	NP_001158255.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BCKDHA	ENST00000269980.7	TSL:1 MANE Select	c.890G>C	p.Arg297Pro	missense	Exon 7 of 9	ENSP00000269980.2
	ENSG00000255730	ENST00000540732.3	TSL:2	c.992G>C	p.Arg331Pro	missense	Exon 8 of 10	ENSP00000443246.1
	BCKDHA	ENST00000457836.6	TSL:2	c.824G>C	p.Arg275Pro	missense	Exon 7 of 9	ENSP00000416000.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152126 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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

GnomAD4 exome Cov.: 33

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152126 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74310

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000242 AC: 1 AN: 41386

American (AMR) AF: 0.00 AC: 0 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.61	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	M
PhyloP100		9.3
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-7.0	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.026	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.84		Loss of stability (P = 0.0299)
MVP		0.95
MPC		2.3
ClinPred		1.0	D
GERP RS		5.7
PromoterAI		0.016	Neutral
Varity_R		1.0
gMVP		0.96
Mutation Taster		=3/97	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs200137189; hg19: chr19-41928570;