rs1286992834

Positions:

• chr1-119755536-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PM5 PP3

The NM_005518.4(HMGCS2):​c.1078T>G​(p.Ser360Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,854 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. S360P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HMGCS2 NM_005518.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.26

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.807

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HMGCS2	NM_005518.4	c.1078T>G	p.Ser360Ala	missense_variant	6/10	ENST00000369406.8	NP_005509.1
HMGCS2	NM_001166107.1	c.952T>G	p.Ser318Ala	missense_variant	5/9		NP_001159579.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HMGCS2	ENST00000369406.8	c.1078T>G	p.Ser360Ala	missense_variant	6/10	1	NM_005518.4	ENSP00000358414	P1
HMGCS2	ENST00000544913.2	c.952T>G	p.Ser318Ala	missense_variant	5/9	2		ENSP00000439495
HMGCS2	ENST00000472375.5	n.525T>G		non_coding_transcript_exon_variant	3/3	5
HMGCS2	ENST00000476640.1	n.809T>G		non_coding_transcript_exon_variant	4/4	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251486 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461854 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727224

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

3-hydroxy-3-methylglutaryl-CoA synthase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 22, 2022

This sequence change replaces serine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 360 of the HMGCS2 protein (p.Ser360Ala). This variant is present in population databases (no rsID available, gnomAD 0.003%). 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 470720). This variant has not been reported in the literature in individuals affected with HMGCS2-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.022	T
BayesDel_noAF	Benign	-0.19
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.73	D;.
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.45	T;T
M_CAP	Benign	0.023	T
MetaRNN	Pathogenic	0.81	D;D
MetaSVM	Benign	-0.50	T
MutationAssessor	Benign	1.0	L;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.54	T
PROVEAN	Uncertain	-2.5	D;D
REVEL	Uncertain	0.55
Sift	Benign	0.49	T;T
Sift4G	Benign	0.44	T;T
Polyphen		0.66	P;.
Vest4		0.69
MutPred		0.63		Loss of phosphorylation at S360 (P = 0.0294);.;
MVP		0.83
MPC		0.47
ClinPred		0.88	D
GERP RS		5.3
Varity_R		0.36
gMVP		0.35

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

Other links and lift over

dbSNP: rs1286992834; hg19: chr1-120298159;