chr19-41422643-G-C

Variant names:

• chr19-41422643-G-C
• rs137852871
• NM_000709.4:c.868G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_000709.4(BCKDHA):​c.868G>C​(p.Gly290Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,792 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BCKDHA NM_000709.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.30

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]

ENSG00000255730 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 19-41422643-G-C is Pathogenic according to our data. Variant chr19-41422643-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3393412.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCKDHA	NM_000709.4	c.868G>C	p.Gly290Arg	missense_variant	Exon 7 of 9	ENST00000269980.7	NP_000700.1
BCKDHA	NM_001164783.2	c.865G>C	p.Gly289Arg	missense_variant	Exon 7 of 9		NP_001158255.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCKDHA	ENST00000269980.7	c.868G>C	p.Gly290Arg	missense_variant	Exon 7 of 9	1	NM_000709.4	ENSP00000269980.2
ENSG00000255730	ENST00000540732.3	c.970G>C	p.Gly324Arg	missense_variant	Exon 8 of 10	2		ENSP00000443246.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251368 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135872

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461792 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727194

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Maple syrup urine disease type 1A Pathogenic:1

-

Neuberg Centre For Genomic Medicine, NCGM

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The missense c.868G>C p.Gly290Arg variant in the BCKDHA gene which is located in a mutational hot spot has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. Different amino acid change p.Gly290Arg is reported as a known pathogenic variant Zeynalzadeh et al., 2018. This variant is reported with the allele frequency 0.0003% in the gnomAD Exomes. The amino acid Glycine at position 290 is changed to a Arginine changing protein sequence and it might alter its composition and physico-chemical properties. Multiple lines of computational evidence Polyphen - Damaging, SIFT - Damaging and MutationTaster - Disease causing predict a damaging effect on protein structure and function for this variant. The amino acid change p.Gly290Arg in BCKDHA is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	.;D;.;.
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D;D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	.;H;.;.
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-5.3	D;D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	.;D;.;.
Vest4		0.97
MutPred		0.93		Gain of MoRF binding (P = 0.0111);.;.;.;
MVP		0.94
MPC		2.0
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.93
gMVP		0.94

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

Other links and lift over

dbSNP: rs137852871; hg19: chr19-41928548;