rs779113356

Positions:

• chr2-26192342-TA-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000182.5(HADHA):​c.1967del​(p.Leu656Ter) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000138 in 1,452,832 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: HADHA NM_000182.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.80

Genes affected

HADHA (HGNC:4801): (hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit alpha) This gene encodes the alpha subunit of the mitochondrial trifunctional protein, which catalyzes the last three steps of mitochondrial beta-oxidation of long chain fatty acids. The mitochondrial membrane-bound heterocomplex is composed of four alpha and four beta subunits, with the alpha subunit catalyzing the 3-hydroxyacyl-CoA dehydrogenase and enoyl-CoA hydratase activities. Mutations in this gene result in trifunctional protein deficiency or LCHAD deficiency. The genes of the alpha and beta subunits of the mitochondrial trifunctional protein are located adjacent to each other in the human genome in a head-to-head orientation. [provided by RefSeq, Jul 2008]

GAREM2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 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 2-26192342-TA-T is Pathogenic according to our data. Variant chr2-26192342-TA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 188712.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HADHA	NM_000182.5	c.1967del	p.Leu656Ter	frameshift_variant	18/20	ENST00000380649.8	NP_000173.2
GAREM2	XM_011532567.4	c.1683+5031del		intron_variant			XP_011530869.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HADHA	ENST00000380649.8	c.1967del	p.Leu656Ter	frameshift_variant	18/20	1	NM_000182.5	ENSP00000370023	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251484 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1452832 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 723480

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000181

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 22, 2017	Variant summary: The HADHA c.1967delT (p.Leu656X) variant results in a premature termination codon, predicted to cause a truncated or absent HADHA protein due to nonsense mediated decay, which are commonly known mechanisms for disease. One in silico tool predicts a damaging outcome for this variant. This variant was found in 1/121390 control chromosomes at a frequency of 0.0000082, which does not exceed the estimated maximal expected allele frequency of a pathogenic HADHA variant (0.0019365). This variant has been reported in multiple patients as compound heterozygotes (Ibdah_!999 and Boutron_2011). One of patients showed 26% of residual LCHAD activity relative to the controls mean in fibroblasts and 2% of residual LKAT activity relative to the controls mean (Boutron_2011). In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic/likely pathogenic. Taken together, this variant is classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Aug 21, 2023	- -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Mar 04, 2014	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Aug 11, 2016

The c.1967delT has previously been reported as c.1964delT in association with LCHAD deficiency (Ibdah et al., 1999). This variant results in the normal codon, Leucine 656, being replaced by a Stop codon and is denoted p.L656X. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. Therefore we interpret c.1967delT to be a pathogenic variant. -

Mitochondrial trifunctional protein deficiency;C3711645:Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 30, 2023

This sequence change creates a premature translational stop signal (p.Leu656*) in the HADHA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in HADHA are known to be pathogenic (PMID: 7738175, 21103935, 21549624, 22459206). This variant is present in population databases (rs779113356, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency or deficiency of mitochondrial trifunctional protein (PMID: 10352164, 21549624). This variant is also known as Leu620Ter. ClinVar contains an entry for this variant (Variation ID: 188712). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs779113356; hg19: chr2-26415211;