1-23808231-T-G

Variant names:

• chr1-23808231-T-G
• NM_000191.3:c.654A>C
• HMGCL p.Leu218Leu

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_000191.3(HMGCL):​c.654A>C​(p.Leu218Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. L218L) has been classified as Benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: HMGCL NM_000191.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.23
• 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: Myriad Women's Health, ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (REVEL=0.08).
• BP7: Synonymous conserved (PhyloP=1.23 with no splicing effect.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCL	NM_000191.3	MANE Select	c.654A>C	p.Leu218Leu	synonymous	Exon 7 of 9	NP_000182.2	P35914-1
	HMGCL	NM_001166059.2		c.441A>C	p.Leu147Leu	synonymous	Exon 5 of 7	NP_001159531.1	P35914-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HMGCL	ENST00000374490.8	TSL:1 MANE Select	c.654A>C	p.Leu218Leu	synonymous	Exon 7 of 9	ENSP00000363614.3	P35914-1
	HMGCL	ENST00000509389.5	TSL:1	n.361-16A>C		intron	N/A
	HMGCL	ENST00000892104.1		c.654A>C	p.Leu218Leu	synonymous	Exon 7 of 10	ENSP00000562163.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 47

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	11
DANN	Benign	0.72
PhyloP100		1.2
Mutation Taster		=92/8	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.13		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: chr1-24134721;