1-119764209-G-T

Variant names:

• chr1-119764209-G-T
• NM_005518.4:c.522C>A
• HMGCS2 p.Phe174Leu

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PS1_Very_Strong PM1 PM2 PP2 PP3_Strong

The NM_005518.4(HMGCS2):​c.522C>A​(p.Phe174Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: HMGCS2 NM_005518.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.81
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• 3-hydroxy-3-methylglutaryl-CoA synthase deficiency

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

ACMG classification

Our verdict: Pathogenic. The variant received 17 ACMG points.

• PS1: Transcript NM_005518.4 (HMGCS2) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_005518.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 13 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: -0.19124 (below the threshold of 3.09). Trascript score misZ: 0.52753 (below the threshold of 3.09). GenCC associations: The gene is linked to 3-hydroxy-3-methylglutaryl-CoA synthase deficiency.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.962

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005518.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCS2	NM_005518.4	MANE Select	c.522C>A	p.Phe174Leu	missense	Exon 2 of 10	NP_005509.1	P54868-1
	HMGCS2	NM_001166107.1		c.522C>A	p.Phe174Leu	missense	Exon 2 of 9	NP_001159579.1	P54868-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCS2	ENST00000369406.8	TSL:1 MANE Select	c.522C>A	p.Phe174Leu	missense	Exon 2 of 10	ENSP00000358414.3	P54868-1
	HMGCS2	ENST00000886233.1		c.549C>A	p.Phe183Leu	missense	Exon 3 of 11	ENSP00000556292.1
	HMGCS2	ENST00000886228.1		c.522C>A	p.Phe174Leu	missense	Exon 2 of 10	ENSP00000556287.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1461472 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727036

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86238

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5434

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112002

Other (OTH) AF: 0.00 AC: 0 AN: 60354

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.83	D
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.37
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.97	D
M_CAP	Benign	0.047	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Benign	1.7	L
PhyloP100		3.8
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.78
Sift	Benign	0.14	T
Sift4G	Benign	0.15	T
Varity_R		0.88
gMVP		0.85
Mutation Taster		=26/74	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr1-120306832;