rs200620279

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3PP5

The NM_014384.3(ACAD8):c.958G>A(p.Ala320Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000236 in 1,613,956 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00018 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00024 ( 1 hom. )

Consequence

ACAD8
NM_014384.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:8U:2

Conservation

PhyloP100: 9.87

Publications

10 publications found

Variant links:

Genes affected

ACAD8 (HGNC:87): (acyl-CoA dehydrogenase family member 8) This gene encodes a member of the acyl-CoA dehydrogenase family of enzymes that catalyze the dehydrogenation of acyl-CoA derivatives in the metabolism of fatty acids or branch chained amino acids. The encoded protein is a mitochondrial enzyme that functions in catabolism of the branched-chain amino acid valine. Defects in this gene are the cause of isobutyryl-CoA dehydrogenase deficiency.[provided by RefSeq, Nov 2009]

ACAD8 Gene-Disease associations (from GenCC):

isobutyryl-CoA dehydrogenase deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, ClinGen, Labcorp Genetics (formerly Invitae)

ACAD8 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.782

PP5

Variant 11-134261756-G-A is Pathogenic according to our data. Variant chr11-134261756-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 372297.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACAD8	NM_014384.3 link	c.958G>A	p.Ala320Thr	missense_variant	Exon 9 of 11	ENST00000281182.9	NP_055199.1	Q9UKU7-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACAD8	ENST00000281182.9 link	c.958G>A	p.Ala320Thr	missense_variant	Exon 9 of 11	1	NM_014384.3	ENSP00000281182.5		Q9UKU7-1

Frequencies

GnomAD3 genomes

AF:

0.000197

AC:

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000622

Gnomad FIN

AF:

0.00113

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000176

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000367

AC:

AN:

250968

AF XY:

0.000398

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.0000993

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00177

Gnomad NFE exome

AF:

0.000361

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.000242

AC:

353

AN:

1461656

Hom.:

Cov.:

AF XY:

0.000254

AC XY:

185

AN XY:

727116

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000894

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.0000765

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.000278

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00175

AC:

AN:

53196

Middle Eastern (MID)

AF:

0.000867

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000187

AC:

208

AN:

1112010

Other (OTH)

AF:

0.000281

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

100

125

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000184

AC:

AN:

152300

Hom.:

Cov.:

AF XY:

0.000201

AC XY:

AN XY:

74468

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41570

American (AMR)

AF:

0.000196

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.000207

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00113

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000176

AC:

AN:

68024

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000299

Hom.:

Bravo

AF:

0.000144

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.000296

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000382

EpiControl

AF:

0.000296

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:8Uncertain:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Deficiency of isobutyryl-CoA dehydrogenase

Pathogenic:6

Dec 05, 2018

Illumina Laboratory Services, Illumina

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The ACAD8 c.958G>A (p.Ala320Thr) missense variant has been reported in a compound heterozygous state in two individuals with isobutyryl-CoA dehydrogenase deficiency who were identified by elevated C4-carnitine levels through newborn screening (Pedersen et al. 2006; Oglesbee et al. 2007). This variant was absent from 415 controls but is reported at a frequency of 0.001563 in the European (Finnish) population of the Genome Aggregation Database. When overexpressed in Chang cells, the p.Ala320Thr variant displayed approximately 20% residual enzyme activity. Experiments in isolated mitochondria also showed the variant reduced isobutyryl-CoA dehydrogenase tetramer formation, suggesting disruption of protein folding (Pedersen et al. 2006). Based on the collective evidence, the p.Ala320Thr variant is classified as likely pathogenic for isobutyryl-CoA dehydrogenase deficiency. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Apr 06, 2021

Genetics and Genomic Medicine Centre, NeuroGen Healthcare, NeuroGen Healthcare

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 26, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 320 of the ACAD8 protein (p.Ala320Thr). This variant is present in population databases (rs200620279, gnomAD 0.2%). This missense change has been observed in individual(s) with isobutyryl-CoA dehydrogenase deficiency (PMID: 16857760, 17304052, 32778825; internal data). This variant is also known as A298T. ClinVar contains an entry for this variant (Variation ID: 372297). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on ACAD8 protein function. Experimental studies have shown that this missense change affects ACAD8 function (PMID: 16857760). For these reasons, this variant has been classified as Pathogenic. -

Jul 08, 2020

Revvity Omics, Revvity

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 19, 2023

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

- -

not provided

Pathogenic:1Uncertain:1

Aug 06, 2025

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Expression studies found that A320T is associated with approximately 20% isobutyryl-CoA dehydrogenase enzyme activity compared to wild-type and that it affects proper isobutyryl-CoA dehydrogenase protein folding (PMID: 16857760); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 16857760, 17304052, 33432785, 34426522, 32778825, 24635911, Lina2023[Article]) -

Apr 12, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

ACAD8-related disorder

Pathogenic:1

Jun 01, 2023

PreventionGenetics, part of Exact Sciences

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The ACAD8 c.958G>A variant is predicted to result in the amino acid substitution p.Ala320Thr. This variant has been reported in the compound heterozygous state in two presumably unrelated individuals with isobutyryl-CoA dehydrogenase deficiency (Table 1, Pedersen et al. 2006. PubMed ID: 16857760; Table 1, Oglesbee et al. 2007. PubMed ID: 17304052). It has been reported in an additional individual with an inborn error of metabolism, but no clinical data was provided (Table S5, Adhikari et al. 2020. PubMed ID: 32778825). It has been reported in the compound heterozygous state in an additional individual with elevated C4-acylcarnitine on newborn screening (Internal Data, PreventionGenetics). This variant has been demonstrated to retain approximately 20% of residual enzymatic activity compared to wild type (Figure 2, Pedersen et al. 2006. PubMed ID: 16857760). This variant is reported in 0.17% of alleles in individuals of European (Finnish) descent in gnomAD (https://gnomad.broadinstitute.org/variant/11-134131650-G-A. This variant is interpreted as likely pathogenic. -

Inborn genetic diseases

Uncertain:1

Jun 04, 2021

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.958G>A (p.A320T) alteration is located in exon 9 (coding exon 9) of the ACAD8 gene. This alteration results from a G to A substitution at nucleotide position 958, causing the alanine (A) at amino acid position 320 to be replaced by a threonine (T). Based on data from the Genome Aggregation Database (gnomAD) database, the ACAD8 c.958G>A alteration was observed in 0.03% (98/282364) of total alleles studied, with a frequency of 0.17% (43/24928) in the European (Finnish) subpopulation. This alteration has been reported in the compound heterozygous state with other ACAD8 variants in two patients with isobutyryl-CoA dehydrogenase deficiency identified by elevated C4-carnitine on newborn screening (Oglesbee, 2007; Pedersen, 2006). One patient was described as having an unremarkable clinical presentation, and the clinical status of the other patient was not determined (Oglesbee, 2007; Pedersen, 2006). This amino acid position is well conserved in available vertebrate species. The p.A320T alteration is predicted to be deleterious by in silico analysis. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.50

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.59

CADD

Uncertain

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.92

D;.

Eigen

Pathogenic

0.93

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.99

D;D

M_CAP

Pathogenic

0.35

MetaRNN

Pathogenic

0.78

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.6

H;.

PhyloP100

9.9

PrimateAI

Uncertain

0.53

PROVEAN

Uncertain

-3.9

D;D

REVEL

Pathogenic

0.92

Sift

Pathogenic

0.0

D;D

Sift4G

Uncertain

0.0030

D;D

Polyphen

1.0

D;.

Vest4

0.99

MVP

1.0

MPC

0.63

ClinPred

0.72

GERP RS

5.7

Varity_R

0.83

gMVP

0.87

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over