19-13136099-C-T
Variant summary
Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM2PP5_Very_Strong
The NM_052876.4(NACC1):c.892C>T(p.Arg298Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. R298L) has been classified as Uncertain significance.
Frequency
Consequence
NM_052876.4 missense
Scores
Clinical Significance
Conservation
Publications
- NACC1-related neurodevelopmental disorder with epilepsy, cataracts and episodic irritabilityInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- neurodevelopmental disorder with epilepsy, cataracts, feeding difficulties, and delayed brain myelinationInheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
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ACMG classification
Our verdict: Pathogenic. The variant received 10 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| NACC1 | NM_052876.4 | c.892C>T | p.Arg298Trp | missense_variant | Exon 2 of 6 | ENST00000292431.5 | NP_443108.1 | |
| NACC1 | XM_005259721.4 | c.892C>T | p.Arg298Trp | missense_variant | Exon 3 of 7 | XP_005259778.1 | ||
| NACC1 | XM_047438118.1 | c.892C>T | p.Arg298Trp | missense_variant | Exon 2 of 6 | XP_047294074.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| NACC1 | ENST00000292431.5 | c.892C>T | p.Arg298Trp | missense_variant | Exon 2 of 6 | 1 | NM_052876.4 | ENSP00000292431.3 | ||
| NACC1 | ENST00000586171.3 | c.892C>T | p.Arg298Trp | missense_variant | Exon 3 of 7 | 5 | ENSP00000467120.2 | |||
| NACC1 | ENST00000700232.1 | c.892C>T | p.Arg298Trp | missense_variant | Exon 2 of 6 | ENSP00000514870.1 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 32
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Neurodevelopmental disorder with epilepsy, cataracts, feeding difficulties, and delayed brain myelination Pathogenic:9
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Variant confirmed as disease-causing by referring clinical team -
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The variant is not observed in the gnomAD v2.1.1 dataset. Predicted Consequence/Location: Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.36 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.82 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000417784 /PMID: 28132692 /3billion dataset). The variant has been previously reported as de novo in a similarly affected individual (PMID: 28132692). The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 28132692). The variant has been previously reported as assumed (i.e. paternity and maternity not confirmed) de novo in at least one similarly affected unrelated individual (3billion dataset). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
The c.892C>T (p.Arg298Trp) variant identified in the NACC1 gene substitutes a well conserved Arginine for Tryptophan at amino acid 298/528 (exon2/6). This variant is absent from gnomAD(v3.1.1) suggesting it is not a common benign variant in the populations represented in that database. In silico algorithms predict this variant to be Damaging (SIFT; score:0.027) and Benign (REVEL; score:0.3639) to the function of the canonical transcript. This variant is reported as Likely Pathogenic / Pathogenic in ClinVar (VarID:417784) and has been identified in many affected individuals in the literature [PMID:28132692; PMID:30842647]. Given its presence in many affected individuals in the literature and its absence in population databases, the c.892C>T (p.Arg298Trp) variant identified in the NACC1 gene is reported as Likely Pathogenic. -
Pathogenic variant based on genotype/phenotype relationship. This patient has been reported in PMID 28132692. -
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not provided Pathogenic:3
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 298 of the NACC1 protein (p.Arg298Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with infantile epilepsy, cataracts, and profound developmental delay (PMID: 28132692). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 417784). 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) performed at Invitae indicates that this missense variant is not expected to disrupt NACC1 protein function with a negative predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -
In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31231135, 31628766, 30842647, 31036916, 31216405, 28132692, 34869110) -
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Inborn genetic diseases Pathogenic:1
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NACC1-related disorder Other:1
Variant interpreted as Pathogenic and reported on 05-07-2020 by Lab or GTR ID 26957. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at