rs1555527513

chr17-7220120-A-C

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1 PM2 PP3_Strong PP5_Very_Strong

The NM_000018.4(ACADVL):c.63-2A>C variant causes a splice acceptor change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000703 in 1,421,994 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: ACADVL NM_000018.4 splice_acceptor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 1.60

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]

ACMG classification

Verdict is Pathogenic. Variant got 22 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.5, offset of 28, new splice context is: tcacggcgctcctggggcAGccc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 17-7220120-A-C is Pathogenic according to our data. Variant chr17-7220120-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 474900.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACADVL	NM_000018.4	c.63-2A>C		splice_acceptor_variant		ENST00000356839.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACADVL	ENST00000356839.10	c.63-2A>C		splice_acceptor_variant		1	NM_000018.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.03e-7 AC: 1 AN: 1421994 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 705142

Gnomad4 AFR exome AF: 0.0000301

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Very long chain acyl-CoA dehydrogenase deficiency Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine	Nov 01, 2019	The NM_000018.3:c.63-2A>C (NP_000009.1:p.?) [GRCH38: NC_000017.11:g.7220120A>C] variant in ACADVL gene is interpretated to be Pathogenic based on ACMG guidelines (PMID: 25741868). This variant has been reported. This variant meets the following evidence codes reported in the ACMG guidelines: PVS1, PS3 -
Likely pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Likely pathogenic, reviewed by expert panel	curation	ClinGen ACADVL Variant Curation Expert Panel, ClinGen	Mar 08, 2022	The c.63-2A>C variant in ACADVL occurs within the canonical splice acceptor site (+/- 1,2) of intron 1. It is predicted to cause skipping of biologically-relevant-exon 2/20, resulting in a frameshift leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1; PMIDs 9973285, 11590124). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant has been reported in an abnormal newborn screen without clinical confirmation or a second pathogenic ACADVL variant identified (PMID 26385305, 27209629). The ACADVL Variant Curation Expert Panel VCEP classified the variant as likely pathogenic based on PVS1+PM2_supporting (VCEP specifications v2.0, approved on 09/16/2021). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 17, 2024	This sequence change affects an acceptor splice site in intron 1 of the ACADVL gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in ACADVL are known to be pathogenic (PMID: 9973285, 11590124). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with very long-chain acyl-CoA dehydrogenase deficiency (PMID: 27209629). ClinVar contains an entry for this variant (Variation ID: 474900). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Benign	-0.25
Cadd	Pathogenic	30
Dann	Benign	0.95
Eigen	Pathogenic	0.77
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.77	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		3.6

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.31		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.31		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1555527513; hg19: chr17-7123439;