NM_000018.4:c.308_309delAA

Variant names:

• chr17-7220794-TAA-T
• rs1057516979
• NM_000018.4:c.308_309delAA

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2_Supporting PVS1

This summary comes from the ClinGen Evidence Repository: The c.308_309del (p.Lys103Argfs*20) variant in ACADVL is a frameshift variant predicted to cause a premature stop codon in biologically-relevant-exon 6/20 leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1; PMIDs: 9973285, 11590124). This variant has been detected in one individual identified by abnormal newborn screening or presumed positive on newborn screening for very long chain acyl CoA dehydrogenase (VLCAD) deficiency with no reported follow-up plasma acylcarnitine or enzyme activity; a second distinct pathogenic or likely pathogenic variant in ACADVL was not reported in this individual (PMID:26385305). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). To our knowledge, functional assays have not been reported for this variant. In summary, this variant meets the criteria to be classified as LIKELY PATHOGENIC for autosomal recessive very long chain acyl-CoA dehydrogenase (VLCAD) deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen ACADVL Variant Curation Expert Panel: PVS1, PM2_Supporting (ClinGen ACADVL VCEP specifications version#2; 05-00-2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA16041859/MONDO:0008723/021

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACADVL NM_000018.4 frameshift
• Clinical Significance: Likely pathogenic reviewed by expert panel P:8
• Conservation: PhyloP100: 1.20
• Publications: 2 publications found

Genes affected

ACADVL (HGNC:92): (acyl-CoA dehydrogenase very long chain) The protein encoded by this gene is targeted to the inner mitochondrial membrane where it catalyzes the first step of the mitochondrial fatty acid beta-oxidation pathway. This acyl-Coenzyme A dehydrogenase is specific to long-chain and very-long-chain fatty acids. A deficiency in this gene product reduces myocardial fatty acid beta-oxidation and is associated with cardiomyopathy. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

ACADVL Gene-Disease associations (from GenCC):

• very long chain acyl-CoA dehydrogenase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, ClinGen, PanelApp Australia, Labcorp Genetics (formerly Invitae)

ACMG classification

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

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000018.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACADVL	NM_000018.4	MANE Select	c.308_309delAA	p.Lys103ArgfsTer20	frameshift	Exon 5 of 20	NP_000009.1
	ACADVL	NM_001270447.2		c.377_378delAA	p.Lys126ArgfsTer20	frameshift	Exon 6 of 21	NP_001257376.1
	ACADVL	NM_001033859.3		c.242_243delAA	p.Lys81ArgfsTer20	frameshift	Exon 4 of 19	NP_001029031.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACADVL	ENST00000356839.10	TSL:1 MANE Select	c.308_309delAA	p.Lys103ArgfsTer20	frameshift	Exon 5 of 20	ENSP00000349297.5
	ACADVL	ENST00000350303.9	TSL:1	c.242_243delAA	p.Lys81ArgfsTer20	frameshift	Exon 4 of 19	ENSP00000344152.5
	ACADVL	ENST00000543245.6	TSL:2	c.377_378delAA	p.Lys126ArgfsTer20	frameshift	Exon 6 of 21	ENSP00000438689.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461784 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727178

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

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: 39700

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53322

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
7	-	-	Very long chain acyl-CoA dehydrogenase deficiency (7)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.2
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs1057516979; hg19: chr17-7124113;