Genetic Variant KYNU:p.Tyr86LeufsTer3 (chr2-142918694-A-AT) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_003937.3(KYNU):c.256dupT(p.Tyr86LeufsTer3) variant causes a frameshift change. The variant allele was found at a frequency of 0.000158 in 1,612,620 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 0.00016 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00016 ( 0 hom. )

Consequence

KYNU
NM_003937.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 6.59

Variant links:

Genes affected

KYNU (HGNC:6469): (kynureninase) Kynureninase is a pyridoxal-5'-phosphate (pyridoxal-P) dependent enzyme that catalyzes the cleavage of L-kynurenine and L-3-hydroxykynurenine into anthranilic and 3-hydroxyanthranilic acids, respectively. Kynureninase is involved in the biosynthesis of NAD cofactors from tryptophan through the kynurenine pathway. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2010]

KYNU links:

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ACMG classification

Classification made for transcript

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 2-142918694-A-AT is Pathogenic according to our data. Variant chr2-142918694-A-AT is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1324639.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
KYNU	NM_003937.3 link	c.256dupT	p.Tyr86LeufsTer3	frameshift_variant	Exon 3 of 14	ENST00000264170.9	NP_003928.1	Q16719-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KYNU	ENST00000264170.9 link	c.256dupT	p.Tyr86LeufsTer3	frameshift_variant	Exon 3 of 14	1	NM_003937.3	ENSP00000264170.4		Q16719-1

Frequencies

GnomAD3 genomes

AF:

0.000158

AC:

AN:

152168

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.000309

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.0000799

AC:

AN:

250196

Hom.:

AF XY:

0.0000665

AC XY:

AN XY:

135276

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.0000995

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000159

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000157

AC:

230

AN:

1460452

Hom.:

Cov.:

AF XY:

0.000156

AC XY:

113

AN XY:

726486

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.0000383

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000206

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.000158

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74336

show subpopulations

Gnomad4 AFR

AF:

0.0000482

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:

0.000309

Gnomad4 OTH

AF:

0.000478

Alfa

AF:

0.000109

Hom.:

Bravo

AF:

0.0000945

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Vertebral, cardiac, renal, and limb defects syndrome 2

Pathogenic:1

Aug 29, 2023

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Criteria applied: PVS1,PM2_SUP -

not provided

Pathogenic:1

Jun 30, 2022

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.Tyr86Leufs*3) in the KYNU gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KYNU are known to be pathogenic (PMID: 17334708, 28792876, 31923704, 34200361). This variant is present in population databases (rs550079487, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with KYNU-related conditions. ClinVar contains an entry for this variant (Variation ID: 1324639). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over