chr19-41423173-A-G

Variant names:

• chr19-41423173-A-G
• rs546655391
• NM_000709.4:c.1167+4A>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000709.4(BCKDHA):​c.1167+4A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000258 in 1,551,974 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BCKDHA NM_000709.4 splice_region, intron
• Scores: Splicing: ADA: 0.9236
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.14
• Publications: 0 publications found

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]

BCKDHA Gene-Disease associations (from GenCC):

• maple syrup urine disease

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• maple syrup urine disease type 1A

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

ENSG00000255730 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.47).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BCKDHA	NM_000709.4	c.1167+4A>G		splice_region_variant, intron_variant	Intron 8 of 8	ENST00000269980.7	NP_000700.1
BCKDHA	NM_001164783.2	c.1164+4A>G		splice_region_variant, intron_variant	Intron 8 of 8		NP_001158255.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BCKDHA	ENST00000269980.7	c.1167+4A>G		splice_region_variant, intron_variant	Intron 8 of 8	1	NM_000709.4	ENSP00000269980.2
ENSG00000255730	ENST00000540732.3	c.1269+4A>G		splice_region_variant, intron_variant	Intron 9 of 9	2		ENSP00000443246.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000632 AC: 1 AN: 158274 AF XY: 0.00

Gnomad AFR exome AF: 0.000111

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000214 AC: 3 AN: 1399770 Hom.: 0 Cov.: 35 AF XY: 0.00000145 AC XY: 1 AN XY: 690644

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000314 AC: 1 AN: 31804

American (AMR) AF: 0.00 AC: 0 AN: 35834

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25162

East Asian (EAS) AF: 0.00 AC: 0 AN: 36144

South Asian (SAS) AF: 0.00 AC: 0 AN: 79330

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49352

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4160

European-Non Finnish (NFE) AF: 9.26e-7 AC: 1 AN: 1080040

Other (OTH) AF: 0.0000173 AC: 1 AN: 57944

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00131091), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74358

African (AFR) AF: 0.0000241 AC: 1 AN: 41458

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.47
CADD	Benign	21
DANN	Benign	0.74
PhyloP100		2.1
PromoterAI		-0.095	Neutral
Mutation Taster		=80/20	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.92
dbscSNV1_RF	Benign	0.65
SpliceAI score (max)		0.010		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: rs546655391; hg19: chr19-41929078;