chr6-80343755-C-T

Variant names:

• chr6-80343755-C-T
• rs1554216354
• NM_183050.4:c.1130C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000056.5(BCKDHB):​c.1130C>T​(p.Pro377Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,734 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BCKDHB NM_000056.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.45
• Publications: 0 publications found

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]

BCKDHB Gene-Disease associations (from GenCC):

• maple syrup urine disease type 1B

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

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• 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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000056.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 51 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: -0.17637 (below the threshold of 3.09). Trascript score misZ: -0.0026186 (below the threshold of 3.09). GenCC associations: The gene is linked to classic maple syrup urine disease, thiamine-responsive maple syrup urine disease, intermittent maple syrup urine disease, intermediate maple syrup urine disease, maple syrup urine disease type 1B, maple syrup urine disease.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.953

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000056.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BCKDHB	NM_183050.4	MANE Select	c.1130C>T	p.Pro377Leu	missense	Exon 10 of 10	NP_898871.1
	BCKDHB	NM_000056.5		c.1130C>T	p.Pro377Leu	missense	Exon 10 of 11	NP_000047.1
	BCKDHB	NM_001424036.1		c.1130C>T	p.Pro377Leu	missense	Exon 10 of 11	NP_001410965.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BCKDHB	ENST00000320393.9	TSL:1 MANE Select	c.1130C>T	p.Pro377Leu	missense	Exon 10 of 10	ENSP00000318351.5
	BCKDHB	ENST00000356489.9	TSL:1	c.1130C>T	p.Pro377Leu	missense	Exon 10 of 11	ENSP00000348880.5
	BCKDHB	ENST00000929318.1		c.1250C>T	p.Pro417Leu	missense	Exon 11 of 11	ENSP00000599377.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461734 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727180

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39656

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111930

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Maple syrup urine disease (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	H
PhyloP100		7.4
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-9.4	D
REVEL	Pathogenic	0.81
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.017	D
Polyphen		1.0	D
Vest4		0.91
MutPred		0.78		Gain of ubiquitination at K379 (P = 0.072)
MVP		0.99
MPC		0.78
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.96
gMVP		0.97
Mutation Taster		=5/95	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1554216354; hg19: chr6-81053472; COSMIC: COSV104627537;