1-119748769-T-C

Position:

• chr1-119748769-T-C

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 2P and 10B. PM2 BP4_Strong BP6_Moderate BS1

The NM_005518.4(HMGCS2):​c.*78A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0019 in 152,338 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.0019 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: HMGCS2 NM_005518.4 3_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.180

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 Benign. Variant got -8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BP6: Variant 1-119748769-T-C is Benign according to our data. Variant chr1-119748769-T-C is described in ClinVar as [Likely_benign]. Clinvar id is 292325.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.0019 (289/152338) while in subpopulation SAS AF= 0.00436 (21/4820). AF 95% confidence interval is 0.00292. There are 0 homozygotes in gnomad4. There are 146 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HMGCS2	NM_005518.4	c.*78A>G		3_prime_UTR_variant	10/10	ENST00000369406.8
HMGCS2	NM_001166107.1	c.*78A>G		3_prime_UTR_variant	9/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HMGCS2	ENST00000369406.8	c.*78A>G		3_prime_UTR_variant	10/10	1	NM_005518.4	P1
HMGCS2	ENST00000544913.2	c.*78A>G		3_prime_UTR_variant	9/9	2

Frequencies

GnomAD3 genomes AF: 0.00190 AC: 289 AN: 152220 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000916

Gnomad ASJ AF: 0.000288

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00435

Gnomad FIN AF: 0.000470

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00313

Gnomad OTH AF: 0.00239

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 8 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 6

Gnomad4 NFE exome AF: 0.00

GnomAD4 genome AF: 0.00190 AC: 289 AN: 152338 Hom.: 0 Cov.: 33 AF XY: 0.00196 AC XY: 146 AN XY: 74498

Gnomad4 AFR AF: 0.000722

Gnomad4 AMR AF: 0.000915

Gnomad4 ASJ AF: 0.000288

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00436

Gnomad4 FIN AF: 0.000470

Gnomad4 NFE AF: 0.00313

Gnomad4 OTH AF: 0.00237

Alfa AF: 0.00339 Hom.: 0

Bravo AF: 0.00169

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	6.3
DANN	Benign	0.51

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

LitVar

Other links and lift over

dbSNP: rs143718202; hg19: chr1-120291392;