Genetic Variant ACAT1:p.Ile387Thr (chr11-108146356-T-C) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_000019.4(ACAT1):c.1160T>C(p.Ile387Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,770 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. I387V) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

ACAT1
NM_000019.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 7.78

Publications

1 publications found

Variant links:

Genes affected

ACAT1 (HGNC:93): (acetyl-CoA acetyltransferase 1) This gene encodes a mitochondrially localized enzyme that catalyzes the reversible formation of acetoacetyl-CoA from two molecules of acetyl-CoA. Defects in this gene are associated with 3-ketothiolase deficiency, an inborn error of isoleucine catabolism characterized by urinary excretion of 2-methyl-3-hydroxybutyric acid, 2-methylacetoacetic acid, tiglylglycine, and butanone. [provided by RefSeq, Feb 2009]

ACAT1 Gene-Disease associations (from GenCC):

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

ACAT1 links:

ENSG00000285696 (HGNC:):

ENSG00000285696 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_000019.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr11-108146355-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2955781.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 11-108146356-T-C is Pathogenic according to our data. Variant chr11-108146356-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 429773.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000019.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
ACAT1	NM_000019.4	MANE Select	c.1160T>C	p.Ile387Thr	missense	Exon 11 of 12	NP_000010.1
ACAT1	NM_001386677.1		c.1160T>C	p.Ile387Thr	missense	Exon 11 of 12	NP_001373606.1
ACAT1	NM_001386681.1		c.890T>C	p.Ile297Thr	missense	Exon 11 of 12	NP_001373610.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
ACAT1	ENST00000265838.9	TSL:1 MANE Select	c.1160T>C	p.Ile387Thr	missense	Exon 11 of 12	ENSP00000265838.4
ACAT1	ENST00000672354.1		c.1160T>C	p.Ile387Thr	missense	Exon 11 of 12	ENSP00000500490.1
ACAT1	ENST00000672284.1		c.890T>C	p.Ile297Thr	missense	Exon 11 of 12	ENSP00000500444.1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251306

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461578

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727106

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39634

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111846

Other (OTH)

AF:

0.0000331

AC:

AN:

60374

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

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:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74354

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.000192

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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:

0.00

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Deficiency of acetyl-CoA acetyltransferase

Pathogenic:5

May 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 387 of the ACAT1 protein (p.Ile387Thr). This variant is present in population databases (rs748303093, gnomAD 0.01%). This missense change has been observed in individual(s) with beta-ketothiolase deficiency (PMID: 28726122). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 429773). 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 ACAT1 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic.

Jul 20, 2017

Yale Center for Mendelian Genomics, Yale University

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

May 05, 2019

Department of Pediatrics, Gifu University

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:literature only

Jan 18, 2024

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 16, 2020

Natera, Inc.

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

not provided

Pathogenic:1

Oct 02, 2015

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The I387T variant in the ACAT1 gene has not been published as a pathogenic variant, nor has it been reported as a benign polymorphism to our knowledge. The I387T variant 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 I387T variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. Missense variants in nearby residues (G379V, A380T, S390P, H397D) have been reported in the Human Gene Mutation Database in association with acetoacetyl-CoA thiolase deficiency (also known as alpha-methylacetoacetic aciduria) (Stenson et al., 2014), supporting the functional importance of this region of the protein. The I387T variant is a strong candidate for a pathogenic variant, however the possibility it may be a rare benign variant cannot be excluded

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.69

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.71

Eigen

Pathogenic

0.84

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.48

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

0.96

MutationAssessor

Pathogenic

3.1

PhyloP100

7.8

PrimateAI

Uncertain

0.59

PROVEAN

Pathogenic

-4.7

REVEL

Pathogenic

0.95

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.96

MutPred

0.93

Gain of disorder (P = 0.013)

MVP

0.97

MPC

0.72

ClinPred

1.0

GERP RS

4.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.90

gMVP

0.96

Mutation Taster

=15/85

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over