rs386833649
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000310.4(PPT1):c.490C>T(p.Arg164*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,874 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. R164R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000310.4 stop_gained
Scores
Clinical Significance
Conservation
Publications
- neuronal ceroid lipofuscinosisInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- neuronal ceroid lipofuscinosis 1Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen, G2P, Orphanet, Myriad Women’s Health
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ACMG classification
Our verdict: Pathogenic. The variant received 18 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| PPT1 | NM_000310.4 | c.490C>T | p.Arg164* | stop_gained | Exon 5 of 9 | ENST00000642050.2 | NP_000301.1 | |
| PPT1 | NM_001363695.2 | c.490C>T | p.Arg164* | stop_gained | Exon 5 of 8 | NP_001350624.1 | ||
| PPT1 | NM_001142604.2 | c.181C>T | p.Arg61* | stop_gained | Exon 2 of 6 | NP_001136076.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| PPT1 | ENST00000642050.2 | c.490C>T | p.Arg164* | stop_gained | Exon 5 of 9 | NM_000310.4 | ENSP00000493153.1 |
Frequencies
GnomAD3 genomes Cov.: 31
GnomAD2 exomes AF: 0.00000795 AC: 2AN: 251428 AF XY: 0.00000736 show subpopulations
GnomAD4 exome AF: 0.00000821 AC: 12AN: 1461874Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5AN XY: 727242 show subpopulations
Age Distribution
GnomAD4 genome Cov.: 31
ClinVar
Submissions by phenotype
Neuronal ceroid lipofuscinosis 1 Pathogenic:6
This submission and the accompanying classification are no longer maintained by the submitter.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.
This sequence change creates a premature translational stop signal (p.Arg164*) in the PPT1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PPT1 are known to be pathogenic (PMID: 10679943, 21990111). This variant is present in population databases (rs386833649, gnomAD 0.006%). This premature translational stop signal has been observed in individuals with neuronal ceroid lipofuscinosis (PMID: 9664077, 10649502). ClinVar contains an entry for this variant (Variation ID: 56197). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.
The homozygous p.Arg164Ter variant in PPT1 was identified by our study in two siblings with neuronal ceroid lipofuscinosis. The p.Arg164Ter variant in PPT1 has been previously reported in four unrelated individuals with neuronal ceroid lipofuscinosis 1 (PMID: 31741823, PMID: 21990111, PMID: 10649502, PMID: 9664077), but has been identified in 0.005% (1/18394) of East Asian chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs386833649). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. Of the four affected individuals previously reported (PMID: 31741823, PMID: 21990111, PMID: 10649502, PMID: 9664077), three were compound heterozygotes who carried pathogenic or likely pathogenic variants in trans (PMID: 31741823, PMID: 21990111, PMID: 9664077, ClinVar Variation ID: 8904), and one was a compound heterozygote who carried a variant of uncertain significance in trans (PMID: 10649502, ClinVar Variation ID: 56217), and the affected siblings identified by our study were homozygotes, which increases the likelihood that the p.Arg164Ter variant is pathogenic. This variant has also been reported in ClinVar (Variation ID: 56197) and has been interpreted as pathogenic by Invitae and the Shahid Beheshti University of Medical Sciences Genomic Research Center and as likely pathogenic by Counsyl. This nonsense variant leads to a premature termination codon at position 164, which is predicted to lead to a truncated or absent protein. Loss of function of the PPT1 gene is an established mechanism of autosomal recessive neuronal ceroid lipofuscinosis 1. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive neuronal ceroid lipofuscinosis 1. ACMG/AMP Criteria applied: PVS1, PM2_Supporting, PM3_Strong (Richards 2015).
not provided Pathogenic:1
Nonsense 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; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 25525159, 28367323, 21990111, 21704547, 24997880, 10649502, 31741823, 9664077)
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at