NM_183050.4:c.988G>A

Variant names:

• chr6-80273171-G-A
• rs1224101411
• NM_183050.4:c.988G>A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_183050.4(BCKDHB):​c.988G>A​(p.Glu330Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,342 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BCKDHB NM_183050.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.23

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 Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 6-80273171-G-A is Pathogenic according to our data. Variant chr6-80273171-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 557381.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCKDHB	NM_183050.4	c.988G>A	p.Glu330Lys	missense_variant	Exon 9 of 10	ENST00000320393.9	NP_898871.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCKDHB	ENST00000320393.9	c.988G>A	p.Glu330Lys	missense_variant	Exon 9 of 10	1	NM_183050.4	ENSP00000318351.5
BCKDHB	ENST00000356489.9	c.988G>A	p.Glu330Lys	missense_variant	Exon 9 of 11	1		ENSP00000348880.5
BCKDHB	ENST00000468520.1	n.218G>A		non_coding_transcript_exon_variant	Exon 3 of 3	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 250962 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135606

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: 0.00000205 AC: 3 AN: 1461342 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726976

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Maple syrup urine disease Pathogenic:4

Sep 20, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 07, 2021

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 22, 2018

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 330 of the BCKDHB protein (p.Glu330Lys). This variant is present in population databases (no rsID available, gnomAD 0.003%). This missense change has been observed in individual(s) with maple syrup urine disease (PMID: 27507644; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 557381). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt BCKDHB protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Maple syrup urine disease type 1B Pathogenic:1

May 25, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	.;D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.8	H;H
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.8	D;D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.99
MutPred		0.94		Gain of ubiquitination at E330 (P = 0.0351);Gain of ubiquitination at E330 (P = 0.0351);
MVP		0.99
MPC		0.82
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.99
gMVP		0.97

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: rs1224101411; hg19: chr6-80982888;