rs781630355

Variant names:

• chr15-40411620-AT-A
• rs781630355
• NM_002225.5:c.618delT

Variant summary

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

The NM_002225.5(IVD):​c.618delT​(p.Ile206MetfsTer40) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,614,000 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: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000026 (0 hom.)
• Consequence: IVD NM_002225.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 7.65

Genes affected

IVD (HGNC:6186): (isovaleryl-CoA dehydrogenase) Isovaleryl-CoA dehydrogenase (IVD) is a mitochondrial matrix enzyme that catalyzes the third step in leucine catabolism. The genetic deficiency of IVD results in an accumulation of isovaleric acid, which is toxic to the central nervous system and leads to isovaleric acidemia. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Aug 2017]

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 15-40411620-AT-A is Pathogenic according to our data. Variant chr15-40411620-AT-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 459930.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IVD	NM_002225.5	c.618delT	p.Ile206MetfsTer40	frameshift_variant	Exon 6 of 12	ENST00000487418.8	NP_002216.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IVD	ENST00000487418.8	c.618delT	p.Ile206MetfsTer40	frameshift_variant	Exon 6 of 12	1	NM_002225.5	ENSP00000418397.3

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152140 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000278 AC: 7 AN: 251488 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135920

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: 0.0000615

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000260 AC: 38 AN: 1461860 Hom.: 0 Cov.: 33 AF XY: 0.0000303 AC XY: 22 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.0000315

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152140 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74326

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Isovaleryl-CoA dehydrogenase deficiency Pathogenic:5

Apr 12, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: IVD c.618delT (p.Ile206MetfsX40) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 2.8e-05 in 251488 control chromosomes (gnomAD). c.618delT has been reported in the literature to be found in a cohort of newborns confirmed to have inborn errors of metabolism, however, no further details were provided (Adhikari_2020). These report(s) do not provide unequivocal conclusions about association of the variant with Isovaleryl-CoA Dehydrogenase Deficiency. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014, and classified the variant as pathogenic (n=2) or VUS (n=1). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Dec 23, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ile209Metfs*40) in the IVD gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in IVD are known to be pathogenic (PMID: 16602101). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with IVD-related conditions. ClinVar contains an entry for this variant (Variation ID: 459930). For these reasons, this variant has been classified as Pathogenic. -

May 10, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 27, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 12, 2024

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Oct 27, 2020

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs781630355; hg19: chr15-40703819;