1-75724782-GCCAACATGGCA-ACCCCGAGTG

Variant names:

• chr1-75724782-GCCAACATGGCA-ACCCCGAGTG
• rs875989865
• NM_000016.6:c.-6_6delGCCAACATGGCAinsACCCCGAGTG

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1 PS1_Moderate PM2 PP5_Very_Strong

The NM_000016.6(ACADM):​c.-6_6delGCCAACATGGCAinsACCCCGAGTG​(p.Met1fs) variant causes a frameshift, start lost change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACADM NM_000016.6 frameshift, start_lost
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 3.58

Genes affected

ACADM (HGNC:89): (acyl-CoA dehydrogenase medium chain) This gene encodes the medium-chain specific (C4 to C12 straight chain) acyl-Coenzyme A dehydrogenase. The homotetramer enzyme catalyzes the initial step of the mitochondrial fatty acid beta-oxidation pathway. Defects in this gene cause medium-chain acyl-CoA dehydrogenase deficiency, a disease characterized by hepatic dysfunction, fasting hypoglycemia, and encephalopathy, which can result in infantile death. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Pathogenic. The variant received 20 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 244 pathogenic variants in the truncated region.
• PS1: Another start lost variant in NM_000016.6 (ACADM) was described as [Likely_pathogenic] in ClinVar as 555765
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-75724782-GCCAACATGGCA-ACCCCGAGTG is Pathogenic according to our data. Variant chr1-75724782-GCCAACATGGCA-ACCCCGAGTG is described in ClinVar as [Likely_pathogenic]. Clinvar id is 966945.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
ACADM	NM_000016.6	c.-6_6delGCCAACATGGCAinsACCCCGAGTG	p.Met1fs	frameshift_variant, start_lost	Exon 1 of 12	ENST00000370841.9	NP_000007.1
ACADM	NM_000016.6	c.-6_6delGCCAACATGGCAinsACCCCGAGTG		5_prime_UTR_variant	Exon 1 of 12	ENST00000370841.9	NP_000007.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACADM	ENST00000370841.9	c.-6_6delGCCAACATGGCAinsACCCCGAGTG	p.Met1fs	frameshift_variant, start_lost	Exon 1 of 12	1	NM_000016.6	ENSP00000359878.5
ACADM	ENST00000370841	c.-6_6delGCCAACATGGCAinsACCCCGAGTG		5_prime_UTR_variant	Exon 1 of 12	1	NM_000016.6	ENSP00000359878.5

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Medium-chain acyl-coenzyme A dehydrogenase deficiency Pathogenic:2

May 12, 2021

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 11, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the ACADM protein in which other variant(s) (p.Arg29Leu) have been determined to be pathogenic (PMID: 20434380; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 966945). Disruption of the initiator codon has been observed in individual(s) with medium chain acyl-CoA dehydrogenase deficiency (PMID: 23028790, 30675864). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (gnomAD no frequency). This sequence change affects the initiator methionine of the ACADM mRNA. The next in-frame methionine is located at codon 87. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs875989865; hg19: chr1-76190467;