NM_183050.4:c.1A>C

Variant names:

• chr6-80106694-A-C
• NM_183050.4:c.1A>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_Supporting PM2

The NM_183050.4(BCKDHB):​c.1A>C​(p.Met1?) variant causes a initiator codon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000143 in 1,402,802 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BCKDHB NM_183050.4 initiator_codon
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.22

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 71 codons. Genomic position: 80127561. Lost 0.179 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCKDHB	NM_183050.4	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 10	ENST00000320393.9	NP_898871.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCKDHB	ENST00000320393.9	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 10	1	NM_183050.4	ENSP00000318351.5
BCKDHB	ENST00000356489.9	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 11	1		ENSP00000348880.5
BCKDHB	ENST00000369760.8	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 6	3		ENSP00000358775.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000143 AC: 2 AN: 1402802 Hom.: 0 Cov.: 32 AF XY: 0.00000144 AC XY: 1 AN XY: 692504

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: 0.00000185

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Benign	22
DANN	Benign	0.90
DEOGEN2	Benign	0.17	.;T;T
Eigen	Benign	-0.25
Eigen_PC	Benign	-0.15
FATHMM_MKL	Benign	0.52	D
LIST_S2	Uncertain	0.90	D;.;D
M_CAP	Pathogenic	1.0	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Uncertain	0.27	D
PROVEAN	Benign	-0.39	N;N;N
REVEL	Uncertain	0.60
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		0.025	.;B;B
Vest4		0.83
MutPred		0.82		Loss of solvent accessibility (P = 0.0152);Loss of solvent accessibility (P = 0.0152);Loss of solvent accessibility (P = 0.0152);
MVP		0.93
ClinPred		1.0	D
GERP RS		4.2
Varity_R		0.96
gMVP		0.55

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: chr6-80816411;