11-6619387-G-T
Variant summary
Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2
The NM_000391.4(TPP1):c.14C>A(p.Ala5Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00135 in 1,614,190 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A5T) has been classified as Uncertain significance.
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: Benign. The variant received -13 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00122 AC: 185AN: 152186Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.00115 AC: 289AN: 251492 AF XY: 0.00119 show subpopulations
GnomAD4 exome AF: 0.00137 AC: 2001AN: 1461886Hom.: 2 Cov.: 31 AF XY: 0.00138 AC XY: 1002AN XY: 727246 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00121 AC: 185AN: 152304Hom.: 0 Cov.: 32 AF XY: 0.00126 AC XY: 94AN XY: 74480 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:1Benign:4
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Has not been previously published as pathogenic or benign to our knowledge -
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Neuronal ceroid lipofuscinosis 2 Uncertain:4
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This submission and the accompanying classification are no longer maintained by the submitter.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. -
This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
not specified Uncertain:1Benign:1
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Variant summary: TPP1 c.14C>A (p.Ala5Asp) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0014 in 1614190 control chromosomes in the gnomAD database, including 2 homozygotes. In addition, the allele frequency of this variant in Finnish population is slightly higher than the expected maximal pathogenic allele frequency of TPP1. c.14C>A has been reported in the literature in individuals affected with epilepsy (e.g., Al Anazi_2022). However, these report(s) do not provide unequivocal conclusions about association of the variant with TPP1-related conditions. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 36539902). ClinVar contains an entry for this variant (Variation ID: 92884). Based on the evidence outlined above, the variant was classified as likely benign. -
Autosomal recessive spinocerebellar ataxia 7;C1876161:Neuronal ceroid lipofuscinosis 2 Uncertain:1
TPP1 NM_000391.3 exon 1 p.Ala5Asp (c.14C>A): This variant has not been reported in the literature but is present in 0.2% (70/25122) of Finnish alleles in the Genome Aggregation Database (https://gnomad.broadinstitute.org/variant/11-6640618-G-T?dataset=gnomad_r2_1). This variant is present in ClinVar (Variation ID:92884). Evolutionary conservation and computational predictive tools suggest that this variant may not impact the protein. In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain. -
Inborn genetic diseases Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at