rs1057516799

Variant names:

• chr6-80168884-G-T
• rs1057516799
• NM_183050.4:c.487G>T

Variant summary

Our verdict is Pathogenic. The variant received 22 ACMG points: 22P and 0B. PVS1 PS3 PM2 PP5_Very_Strong

The NM_183050.4(BCKDHB):​c.487G>T​(p.Glu163*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,840 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 Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000918643: The most pronounced variant effect results in <10% of normal activity (Fisher_1993).". Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BCKDHB NM_183050.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 9.49
• Publications: 2 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: G2P, Myriad Women’s Health, ClinGen
• 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: Pathogenic. The variant received 22 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV000918643: The most pronounced variant effect results in <10% of normal activity (Fisher_1993).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 6-80168884-G-T is Pathogenic according to our data. Variant chr6-80168884-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 370827.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_183050.4. 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.487G>T	p.Glu163*	stop_gained	Exon 5 of 10	NP_898871.1	P21953-1
	BCKDHB	NM_001424035.1		c.487G>T	p.Glu163*	stop_gained	Exon 5 of 10	NP_001410964.1
	BCKDHB	NM_000056.5		c.487G>T	p.Glu163*	stop_gained	Exon 5 of 11	NP_000047.1	A0A140VKB3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BCKDHB	ENST00000320393.9	TSL:1 MANE Select	c.487G>T	p.Glu163*	stop_gained	Exon 5 of 10	ENSP00000318351.5	P21953-1
	BCKDHB	ENST00000356489.9	TSL:1	c.487G>T	p.Glu163*	stop_gained	Exon 5 of 11	ENSP00000348880.5	P21953-1
	BCKDHB	ENST00000929318.1		c.487G>T	p.Glu163*	stop_gained	Exon 5 of 11	ENSP00000599377.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461840 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111968

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	-	-	Maple syrup urine disease (3)
2	-	-	Maple syrup urine disease type 1B (2)
1	-	-	Maple syrup urine disease type 1A (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	45
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.5
Vest4		0.94
GERP RS		5.1
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1057516799; hg19: chr6-80878601;