rs748038934
Variant summary
Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2
The NM_000391.4(TPP1):c.775C>T(p.Arg259Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000217 in 1,613,840 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R259H) has been classified as Likely benign.
Frequency
Consequence
NM_000391.4 missense
Scores
Clinical Significance
Conservation
Publications
- neuronal ceroid lipofuscinosisInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- neuronal ceroid lipofuscinosis 2Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Myriad Women’s Health, G2P, Orphanet
- autosomal recessive spinocerebellar ataxia 7Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152130Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000199 AC: 5AN: 251350 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000226 AC: 33AN: 1461710Hom.: 0 Cov.: 41 AF XY: 0.0000206 AC XY: 15AN XY: 727178 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152130Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1AN XY: 74314 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:2
Not observed at significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 259 of the TPP1 protein (p.Arg259Cys). This variant is present in population databases (rs748038934, gnomAD 0.005%). This variant has not been reported in the literature in individuals affected with TPP1-related conditions. ClinVar contains an entry for this variant (Variation ID: 572977). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on TPP1 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Inborn genetic diseases Uncertain:1
The p.R259C variant (also known as c.775C>T), located in coding exon 7 of the TPP1 gene, results from a C to T substitution at nucleotide position 775. The arginine at codon 259 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Neuronal ceroid lipofuscinosis 2 Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at