rs121965058

Variant names:

• chr10-124397986-G-A
• rs121965058
• NM_000274.4:c.1276C>T

Your query was ambiguous. Multiple possible variants found:

• chr10-124397986-G-A
• chr10-124397986-G-T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000274.4(OAT):​c.1276C>T​(p.Arg426*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000616 in 1,461,636 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R426R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: OAT NM_000274.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 2.56
• Publications: 5 publications found

Genes affected

OAT (HGNC:8091): (ornithine aminotransferase) This gene encodes the mitochondrial enzyme ornithine aminotransferase, which is a key enzyme in the pathway that converts arginine and ornithine into the major excitatory and inhibitory neurotransmitters glutamate and GABA. Mutations that result in a deficiency of this enzyme cause the autosomal recessive eye disease Gyrate Atrophy. Alternatively spliced transcript variants encoding different isoforms have been described. Related pseudogenes have been defined on the X chromosome. [provided by RefSeq, Jan 2010]

OAT Gene-Disease associations (from GenCC):

• ornithine aminotransferase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P, Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0333 CDS is truncated, and there are 2 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 10-124397986-G-A is Pathogenic according to our data. Variant chr10-124397986-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 177.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
OAT	NM_000274.4	c.1276C>T	p.Arg426*	stop_gained	Exon 10 of 10	ENST00000368845.6	NP_000265.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
OAT	ENST00000368845.6	c.1276C>T	p.Arg426*	stop_gained	Exon 10 of 10	1	NM_000274.4	ENSP00000357838.5
OAT	ENST00000539214.5	c.862C>T	p.Arg288*	stop_gained	Exon 9 of 9	1		ENSP00000439042.1
OAT	ENST00000471127.1	n.*35C>T		downstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250712 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461636 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727120

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.0000224 AC: 1 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.0000756 AC: 3 AN: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53360

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111864

Other (OTH) AF: 0.0000166 AC: 1 AN: 60376

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ornithine aminotransferase deficiency Pathogenic:5

Jul 01, 1992

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Aug 29, 2023

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. Experimental studies have shown that this premature translational stop signal affects OAT function (PMID: 23076989). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. ClinVar contains an entry for this variant (Variation ID: 177). This premature translational stop signal has been observed in individual(s) with gyrate atrophy (PMID: 1609808, 24429551). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is present in population databases (rs121965058, gnomAD 0.003%). This sequence change creates a premature translational stop signal (p.Arg426*) in the OAT gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 14 amino acid(s) of the OAT protein. -

Aug 29, 2023

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 09, 2021

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 18, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hyperornithinemia Pathogenic:1

Jun 14, 2022

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: OAT c.1276C>T (p.Arg426X) results in a premature termination codon in the last exon of the protein, 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. The variant allele was found at a frequency of 4e-06 in 250712 control chromosomes (gnomAD). c.1276C>T has been reported in the literature in homozygous and compound heterozygous individuals affected with Ornithine Aminotransferase Deficiency (examples: Katagiri_2014 and Mashima_1994). These data indicate that the variant is very likely to be associated with disease. In yeast this variant effect results in <10% of normal activity (Doimo_2012). Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Benign	0.50	N
PhyloP100		2.6
Vest4		0.73
GERP RS		4.1
Mutation Taster		=7/193	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs121965058; hg19: chr10-126086555;