rs770642379

Variant summary

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

The NM_003937.3(KYNU):​c.1045_1051del​(p.Phe349LysfsTer4) variant causes a frameshift, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000969 in 1,609,320 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (β˜…β˜…). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00010 ( 0 hom. )

Consequence

KYNU
NM_003937.3 frameshift, splice_region

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 7.45
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]

Genome browser will be placed here

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 2-143040429-TCTTTAAG-T is Pathogenic according to our data. Variant chr2-143040429-TCTTTAAG-T is described in ClinVar as [Pathogenic]. Clinvar id is 403731.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-143040429-TCTTTAAG-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
KYNUNM_003937.3 linkuse as main transcriptc.1045_1051del p.Phe349LysfsTer4 frameshift_variant, splice_region_variant 13/14 ENST00000264170.9 NP_003928.1
KYNUNM_001199241.2 linkuse as main transcriptc.1045_1051del p.Phe349LysfsTer4 frameshift_variant, splice_region_variant 14/15 NP_001186170.1

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
KYNUENST00000264170.9 linkuse as main transcriptc.1045_1051del p.Phe349LysfsTer4 frameshift_variant, splice_region_variant 13/141 NM_003937.3 ENSP00000264170 P1Q16719-1
KYNUENST00000409512.5 linkuse as main transcriptc.1045_1051del p.Phe349LysfsTer4 frameshift_variant, splice_region_variant 14/151 ENSP00000386731 P1Q16719-1

Frequencies

GnomAD3 genomes
AF:
0.0000263
AC:
4
AN:
152042
Hom.:
0
Cov.:
32
show subpopulations
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:
0.0000319
AC:
8
AN:
250432
Hom.:
0
AF XY:
0.0000369
AC XY:
5
AN XY:
135328
show subpopulations
Gnomad AFR exome
AF:
0.0000616
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:
0.0000619
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000104
AC:
152
AN:
1457278
Hom.:
0
AF XY:
0.000106
AC XY:
77
AN XY:
725204
show subpopulations
Gnomad4 AFR exome
AF:
0.0000300
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:
0.000136
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
AF:
0.0000263
AC:
4
AN:
152042
Hom.:
0
Cov.:
32
AF XY:
0.0000269
AC XY:
2
AN XY:
74272
show subpopulations
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
Alfa
AF:
0.0000434
Hom.:
0
Bravo
AF:
0.0000302

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Vertebral, cardiac, renal, and limb defects syndrome 2 Pathogenic:3
Pathogenic, criteria provided, single submitterclinical testingMolecular Genetics, Royal Melbourne HospitalMay 05, 2023This sequence change in KYNU is a frameshift variant predicted to cause a premature stop codon, p.(Phe349Lysfs*4), in biologically relevant exon 13/14 leading to nonsense-mediated decay in a gene in which loss-of-function is an established disease mechanism (PMID: 28792876). The highest population minor allele frequency in the population database gnomAD v2.1 is 0.006% (8/128,530 alleles) in the European (non-Finnish) population, which is consistent with vertebral, cardiac, renal, and limb defects syndrome. This variant has been detected in an individual with vertebral, cardiac, renal, and limb defects syndrome compound heterozygous with a pathogenic variant and was confirmed in trans by parental testing (PMID: 28792876). Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.6.1, this variant is classified as PATHOGENIC. Following criteria are met: PVS1, PM3, PM2_Supporting. -
Pathogenic, no assertion criteria providedliterature onlyOMIMMar 06, 2024- -
Pathogenic, criteria provided, single submitterclinical testingBaylor GeneticsSep 29, 2023- -
not provided Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingGeneDxNov 07, 2023Frameshift 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; Published functional studies demonstrate a damaging effect on enzyme activity (PMID: 28792876); This variant is associated with the following publications: (PMID: 28792876) -
Congenital NAD deficiency disorder Pathogenic:1
Pathogenic, criteria provided, single submitterresearchEmbryology Laboratory, Victor Chang Cardiac Research InstituteDec 23, 2016This variant was discovered in a North American family. The patient presented multiple congenital malformations affecting vertebrae, heart, kidney among others. This variant is a protein truncating variant and novel (ExAC MAF 0). The patient is compound heterzygous for this variant and another protein truncating variant in the same KYNU gene (NM_003937.2:c.468T>A). Her unaffected parents are heterzygous for only one variant. Enzyme assay confirmed that the protein product of this gene variant has lost enzyme activity. Mouse embryos homozygous null for Kynu presented similar phenotype as observed in the patient, and also showed reduced concentration of NAD in the embryonic tissue. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction

Splicing

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.

Other links and lift over

dbSNP: rs770642379; hg19: chr2-143797998; API