chr16-71568211-C-T
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM2PM5PP3_StrongPP5_Very_Strong
The NM_000353.3(TAT):c.1298G>A(p.Arg433Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000397 in 1,614,090 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R433W) has been classified as Pathogenic.
Frequency
Consequence
NM_000353.3 missense
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TAT | NM_000353.3 | c.1298G>A | p.Arg433Gln | missense_variant | Exon 12 of 12 | ENST00000355962.5 | NP_000344.1 | |
| TAT-AS1 | NR_103851.1 | n.284+2010C>T | intron_variant | Intron 2 of 2 | ||||
| TAT-AS1 | NR_103852.1 | n.258+2010C>T | intron_variant | Intron 2 of 2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152206Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000278 AC: 7AN: 251422 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000424 AC: 62AN: 1461884Hom.: 0 Cov.: 31 AF XY: 0.0000413 AC XY: 30AN XY: 727242 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152206Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1AN XY: 74366 show subpopulations
ClinVar
Submissions by phenotype
Tyrosinemia type II Pathogenic:3Uncertain:1
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
Variant summary: TAT c.1298G>A (p.Arg433Gln) results in a conservative amino acid change located in the Aminotransferase, class I/class II domain (IPR004839) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.8e-05 in 251422 control chromosomes. c.1298G>A has been reported in the literature as a compound heterozygous genotype in at-least two individuals affected with Tyrosinemia Type 2 who continue to be cited in subsequent reports (example, Huhn_1998, Pena-Quintana_2017). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (Huhn_1998). The most pronounced variant effect results in a drastically reduced TAT enzyme activity in-vitro when compared with the GST-TAT wild type construct. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. One laboratory classified the variant as likely pathogenic and one laboratory classified the variant as uncertain significance citing overlapping evidence utilized in the context of this evaluation. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 433 of the TAT protein (p.Arg433Gln). This variant is present in population databases (rs775488556, gnomAD 0.006%). This missense change has been observed in individual(s) with tyrosinemia type II (PMID: 9544843). 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. ClinVar contains an entry for this variant (Variation ID: 550347). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt TAT protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects TAT function (PMID: 9544843). This variant disrupts the p.Arg433 amino acid residue in TAT. Other variant(s) that disrupt this residue have been observed in individuals with TAT-related conditions (PMID: 9544843), which suggests that this may be a clinically significant amino acid residue. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at