rs779759347

Variant names:

• chr1-75750482-G-C
• rs779759347
• NM_000016.6:c.881G>C

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000016.6(ACADM):​c.881G>C​(p.Arg294Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000144 in 1,460,108 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R294G) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: ACADM NM_000016.6 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 9.20
• Publications: 3 publications found

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]

ACADM Gene-Disease associations (from GenCC):

• medium chain acyl-CoA dehydrogenase deficiency

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

ACMG classification

Our verdict: Pathogenic. The variant received 19 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000016.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-75750481-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 3653361.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 95 curated pathogenic missense variants (we use a threshold of 10). The gene has 29 curated benign missense variants. Gene score misZ: 0.54287 (below the threshold of 3.09). Trascript score misZ: 0.41658 (below the threshold of 3.09). GenCC associations: The gene is linked to medium chain acyl-CoA dehydrogenase deficiency.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.966
• PP5: Variant 1-75750482-G-C is Pathogenic according to our data. Variant chr1-75750482-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 226075.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000016.6. 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
	ACADM	NM_000016.6	MANE Select	c.881G>C	p.Arg294Thr	missense	Exon 10 of 12	NP_000007.1
	ACADM	NM_001286043.2		c.980G>C	p.Arg327Thr	missense	Exon 11 of 13	NP_001272972.1
	ACADM	NM_001127328.3		c.893G>C	p.Arg298Thr	missense	Exon 10 of 12	NP_001120800.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACADM	ENST00000370841.9	TSL:1 MANE Select	c.881G>C	p.Arg294Thr	missense	Exon 10 of 12	ENSP00000359878.5
	ACADM	ENST00000370834.9	TSL:1	c.980G>C	p.Arg327Thr	missense	Exon 11 of 13	ENSP00000359871.5
	ACADM	ENST00000420607.6	TSL:1	c.893G>C	p.Arg298Thr	missense	Exon 10 of 12	ENSP00000409612.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250574 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000144 AC: 21 AN: 1460108 Hom.: 0 Cov.: 31 AF XY: 0.0000151 AC XY: 11 AN XY: 726302

African (AFR) AF: 0.00 AC: 0 AN: 33442

American (AMR) AF: 0.00 AC: 0 AN: 44694

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26106

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 85974

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4760

European-Non Finnish (NFE) AF: 0.0000189 AC: 21 AN: 1111782

Other (OTH) AF: 0.00 AC: 0 AN: 60272

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Medium-chain acyl-coenzyme A dehydrogenase deficiency Pathogenic:5

Jun 15, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ACADM c.881G>C (p.Arg294Thr) results in a non-conservative amino acid change located in the C-terminal domain (IPR009075) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 250574 control chromosomes (i.e. 1 allele in gnomAD v2.1). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.881G>C has been reported in the literature in at least 3 individuals diagnosed with Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCADD) (e.g. McKinney_2004, Adhikari_2020, Li_2022). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. However, nearby missense changes have been reported in affected individuals (HGMD), indicating a functional importance for the protein region. The following publications have been ascertained in the context of this evaluation (PMID: 32778825, 36068006, 15171998, 30675864). Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as pathogenic (n=2)/likely pathogenic (n=2). Based on the evidence outlined above, the variant was classified as likely pathogenic.

Oct 16, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with threonine, which is neutral and polar, at codon 294 of the ACADM protein (p.Arg294Thr). This variant is present in population databases (rs779759347, gnomAD 0.0009%). This missense change has been observed in individual(s) with MCAD deficiency (PMID: 15171998, 30675864). ClinVar contains an entry for this variant (Variation ID: 226075). 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 ACADM protein function. For these reasons, this variant has been classified as Pathogenic.

Mar 25, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Feb 20, 2015

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:1

Sep 29, 2016

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The R294T missense variant in the ACADM gene has been reported in a patient with MCAD deficiency who also harbored the common pathogenic K329E variant on the opposite ACADM allele (in trans) (McKinney et al. 2004). R294T was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The R294T variant is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. In summary, we interpret the R294T variant to be likely pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	29
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.79	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.3	M
PhyloP100		9.2
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-5.6	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.012	D
Sift4G	Benign	0.091	T
Polyphen		1.0	D
Vest4		0.90
MutPred		0.85		Loss of methylation at R327 (P = 0.0549)
MVP		1.0
MPC		0.89
ClinPred		0.98	D
GERP RS		5.8
Varity_R		0.90
gMVP		0.94
Mutation Taster		=0/100	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs779759347; hg19: chr1-76216167;