1-119750831-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_005518.4(HMGCS2):c.1498C>T(p.Arg500Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000186 in 1,613,780 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R500H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

HMGCS2
NM_005518.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 5.67

Variant links:

Genes affected

HMGCS2 (HGNC:5008): (3-hydroxy-3-methylglutaryl-CoA synthase 2) The protein encoded by this gene belongs to the HMG-CoA synthase family. It is a mitochondrial enzyme that catalyzes the first reaction of ketogenesis, a metabolic pathway that provides lipid-derived energy for various organs during times of carbohydrate deprivation, such as fasting. Mutations in this gene are associated with HMG-CoA synthase deficiency. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Oct 2009]

HMGCS2 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-119750830-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 9260.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.979

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HMGCS2	NM_005518.4 linkuse as main transcript	c.1498C>T	p.Arg500Cys	missense_variant	9/10	ENST00000369406.8
HMGCS2	NM_001166107.1 linkuse as main transcript	c.1372C>T	p.Arg458Cys	missense_variant	8/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HMGCS2	ENST00000369406.8 linkuse as main transcript	c.1498C>T	p.Arg500Cys	missense_variant	9/10	1	NM_005518.4	P1	P54868-1
HMGCS2	ENST00000544913.2 linkuse as main transcript	c.1372C>T	p.Arg458Cys	missense_variant	8/9	2			P54868-2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152134

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:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251332

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135834

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000178

AC:

AN:

1461646

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

727130

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000756

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000207

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152134

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74320

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.000479

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

3-hydroxy-3-methylglutaryl-CoA synthase deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 24, 2024

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 500 of the HMGCS2 protein (p.Arg500Cys). This variant is present in population databases (rs756539895, gnomAD 0.003%). This missense change has been observed in individual(s) with 3-hydroxy-3-methylglutaryl-CoA synthase deficiency (PMID: 32952630). 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) has been performed at Invitae 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 HMGCS2 protein function. Experimental studies have shown that this missense change affects HMGCS2 function (PMID: 32952630). This variant disrupts the p.Arg500 amino acid residue in HMGCS2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11479731, 23751782, 32952630). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.33

Cadd

Pathogenic

Dann

Pathogenic

1.0

DEOGEN2

Pathogenic

0.92

D;.

Eigen

Pathogenic

0.74

Eigen_PC

Uncertain

0.61

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Pathogenic

0.98

D;D

M_CAP

Benign

0.083

MetaRNN

Pathogenic

0.98

D;D

MetaSVM

Pathogenic

0.93

MutationAssessor

Pathogenic

4.0

H;.

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.59

PROVEAN

Pathogenic

-7.1

D;D

REVEL

Pathogenic

0.82

Sift

Pathogenic

0.0

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

D;.

Vest4

0.84

MutPred

0.91

Loss of disorder (P = 0.0104);.;

MVP

0.99

MPC

0.58

ClinPred

1.0

GERP RS

5.3

Varity_R

0.83

gMVP

0.69

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over