1-23816737-G-A

Variant names:

• chr1-23816737-G-A
• rs890995574
• NM_000191.3:c.286C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000191.3(HMGCL):​c.286C>T​(p.Gln96*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HMGCL NM_000191.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.31
• Publications: 0 publications found

Genes affected

HMGCL (HGNC:5005): (3-hydroxy-3-methylglutaryl-CoA lyase) The protein encoded by this gene belongs to the HMG-CoA lyase family. It is a mitochondrial enzyme that catalyzes the final step of leucine degradation and plays a key role in ketone body formation. Mutations in this gene are associated with HMG-CoA lyase deficiency. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2009]

HMGCL Gene-Disease associations (from GenCC):

• 3-hydroxy-3-methylglutaric aciduria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, Orphanet, Myriad Women’s Health, ClinGen

ACMG classification

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

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-23816737-G-A is Pathogenic according to our data. Variant chr1-23816737-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 557482.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000191.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCL	NM_000191.3	MANE Select	c.286C>T	p.Gln96*	stop_gained	Exon 4 of 9	NP_000182.2
	HMGCL	NM_001166059.2		c.286C>T	p.Gln96*	stop_gained	Exon 4 of 7	NP_001159531.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCL	ENST00000374490.8	TSL:1 MANE Select	c.286C>T	p.Gln96*	stop_gained	Exon 4 of 9	ENSP00000363614.3
	HMGCL	ENST00000509389.5	TSL:1	n.298C>T		non_coding_transcript_exon	Exon 4 of 6
	HMGCL	ENST00000436439.6	TSL:2	c.286C>T	p.Gln96*	stop_gained	Exon 4 of 7	ENSP00000389281.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Deficiency of hydroxymethylglutaryl-CoA lyase Pathogenic:3

Jun 02, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 557482). This premature translational stop signal has been observed in individual(s) with HMG-CoA lyase deficiency (PMID: 11461194). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln96*) in the HMGCL gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in HMGCL are known to be pathogenic (PMID: 9817922, 17692550, 23465862).

Mar 27, 2018

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Apr 11, 2023

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Uncertain	0.91	D
PhyloP100		1.3
Vest4		0.45
GERP RS		3.9
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs890995574; hg19: chr1-24143227;