NM_016042.4:c.395A>C
Variant summary
Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PP3_ModeratePP5_Very_Strong
The NM_016042.4(EXOSC3):c.395A>C(p.Asp132Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000706 in 1,613,954 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. D132D) has been classified as Likely benign.
Frequency
Consequence
NM_016042.4 missense
Scores
Clinical Significance
Conservation
Publications
- pontocerebellar hypoplasia type 1BInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, Illumina
- pontocerebellar hypoplasia type 1Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 10 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| EXOSC3 | ENST00000327304.10 | c.395A>C | p.Asp132Ala | missense_variant | Exon 2 of 4 | 1 | NM_016042.4 | ENSP00000323046.4 | ||
| ENSG00000255872 | ENST00000540557.1 | n.*831A>C | non_coding_transcript_exon_variant | Exon 9 of 12 | 5 | ENSP00000457548.1 | ||||
| ENSG00000255872 | ENST00000540557.1 | n.*831A>C | 3_prime_UTR_variant | Exon 9 of 12 | 5 | ENSP00000457548.1 |
Frequencies
GnomAD3 genomes AF: 0.000480 AC: 73AN: 152206Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000406 AC: 102AN: 251366 AF XY: 0.000397 show subpopulations
GnomAD4 exome AF: 0.000729 AC: 1066AN: 1461748Hom.: 0 Cov.: 31 AF XY: 0.000747 AC XY: 543AN XY: 727174 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000480 AC: 73AN: 152206Hom.: 0 Cov.: 32 AF XY: 0.000444 AC XY: 33AN XY: 74356 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Pontocerebellar hypoplasia type 1B Pathogenic:26
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Variant confirmed as disease-causing by referring clinical team -
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The c.395A>C;p.(Asp132Ala) missense variant has been observed in affected individual(s) and ClinVar contains an entry for this variant (ClinVar ID: 31688; PMID: 23975261; 28687512; 30986545; 23564332; 23564332; 29656927; 24524299; 27146152; 24970098; 23883322; 22544365) -. PS4.The variant is present at low allele frequencies population databases (rs141138948– gnomAD 0.004796%; ABraOM 0.000854 frequency - http://abraom.ib.usp.br/) - PM2_supporting. The p.(Asp132Ala) was detected in trans with a pathogenic variant (PMID: 23975261; 28687512; 23564332; 23564332; 24524299; 24524299; 27146152) -PM3_very strong The variant co-segregated with disease in multiple affected family members (PMID: 23975261; 30986545; 23564332; 27146152) - PP1_strong. Multiple lines of computational evidence support a deleterious effect on the gene or gene product - PP3. In summary, the currently available evidence indicates that the variant is pathogenic. -
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Criteria applied: PM3_VSTR,PS3_SUP,PM2_SUP,PP3 -
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This sequence change replaces aspartic acid, which is acidic and polar, with alanine, which is neutral and non-polar, at codon 132 of the EXOSC3 protein (p.Asp132Ala). This variant is present in population databases (rs141138948, gnomAD 0.07%). This missense change has been observed in individuals with pontocerebellar hypoplasia (PMID: 22544365, 23975261, 24524299, 25533962). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 31688). 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 EXOSC3 protein function with a positive predictive value of 95%. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on EXOSC3 function (PMID: 22544365, 27777260, 28687512). For these reasons, this variant has been classified as Pathogenic. -
The c.395A>C, p.Asp132Ala missense variant identified in the EXOSC3 gene has been reported previously in multiple unrelated individuals with pontocerebellar hypoplasia type 1 [PMID: 22544365; PMID: 25149867; PMID: 23975261; PMID: 24524299; PMID: 29656927]. This variant has a frequency of 0.05% (69 heterozygous out of 143304 alleles) in gnomAD database which is low enough to be consistent with a recessive carrier frequency. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. Based on the available evidence, the variant c.395A>C, p.Asp132Ala in the EXOSC3 gene is classified as pathogenic. -
PM3_VS, PP1, PP3, PM2 -
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A Homozygote Missense variant c.395A>C in Exon 2 of the EXOSC3 gene that results in the amino acid substitution p.Asp132Ala was identified. The observed variant has a minor allele frequency of 0.00041/0.00041% in gnomAD exomes and genomes, respectively. The severity of the impact of this variant on the protein is medium, based on the effect of the protein and REVEL score. Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. The variant has been reported to ClinVar as Pathogenic with a status of (2 stars) criteria provided, multiple submitters, no conflicts (Variation ID 31688 as of 2022-12-24). The c.395A>C, p.Asp132Ala missense variant identified in the EXOSC3 gene has been reported previously in multiple unrelated individuals with pontocerebellar hypoplasia type 1 (Wan, Jijun et al., 2012). Functionally, the variant causes dysfunctional exosome complex (Schottmann, Gudrun et al., 2017). Based on the above evidence this variant has been classified as Pathogenic according to the ACMG guidelines. -
Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with pontocerebellar hypoplasia, type 1B (MIM#614678). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from aspartic acid to alanine. (I) 0252 - This variant is homozygous. (I) 0304 - Variant is present in gnomAD v2 <0.01 for a recessive condition (115 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (9 heterozygotes, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated RNA binding S1 domain (PMID: 22544365). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported multiple times as pathogenic and likely pathogenic, and has been reported in many homozygous and compound heterozygous patients with pontocerebellar hypoplasia (ClinVar, PMID: 22544365). (SP) 1209 - This variant has been shown to be both maternally and paternally inherited (biallelic) (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
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ACMG classification criteria: PS4 moderate, PM2 moderate, PM3 very strong, PP1 strong, PP3 supporting -
The EXOSC3 c.395A>C p.(Asp132Ala) missense variant has been identified in individuals with a phenotype consistent with pontocerebellar hypoplasia (Wan et al. 2012; Biancheri et al. 2013; Rudnik-Schöneborn et al. 2013; Zanni et al. 2013; Eggens et al. 2014; Schottman et al. 2017). At least one study indicated that a milder phenotype was observed when the variant was present in a homozygous state, but was more severe in individuals carrying the variant in a compound heterozygous state (Rudnik-Schöneborn et al. 2013). The highest frequency of this allele in the Genome Aggregation Database is 0.000904 in the European (non-Finnish) population (version 2.1.1). Morpholino knockdown of exosc3 in zebrafish embryos recapitulated the human phenotype; rescue of the abnormal phenotype was less effective with variant protein than wildtype protein (Wan et al. 2012). Functional studies in patient fibroblasts showed that the variant protein was largely retained in the cytosol and Golgi system compared with the speckled distribution in the nucleus of control cells (Schottman et al. 2017). Additionally, structural models in yeast Rrp40 demonstrate that the p.Asp132Ala variant impairs formation of a loop in the S1 domain, which is essential for interfacing with EXOSC5 and EXOSC9 (Fasken et al. 2017). Based on the collective evidence, the c.395A>C p.(Asp132Ala)variant is classified as pathogenic for pontocerebellar hypoplasia. -
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This mutation has been previously reported as disease-causing and was found once in our laboratory homozygous in a 7-year-old male with severe intellectual disability, hypotonia, progressive dystonia, dysmorphism, microcephaly, progressive contractures, failure to thrive, and a similarly affected sibling -
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The homozygous p.Asp132Ala variant in EXOSC3 was identified by our study in one individual with pontocerebellar hypoplasia. The p.Asp132Ala variant in EXOSC3 has been reported in 28 individuals with pontocerebellar hypoplasia, segregated with disease in 28 individuals with pontocerebellar hypoplasia with a variety of ethnic backgrounds (including Cuban, Canadian, European, Turkish, American, and Australian) and segregated with disease in 4 affected relatives from 2 families (PMID: 29656927, 22544365, 23975261, 24524299), and has been identified in 0.07279% (94/129130) of European (non-Finnish) chromosome by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs141138948). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. Computational prediction tools and conservational analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. The presence of this variant in combination with 8 variants (including 3 loss of function variants) and in individuals with pontocerebellar hypoplasia increases the likelihood that the p.Asp132Ala variant is pathogenic (PMID: 23975261, 22544365, 24524299; Variation ID: 129024, 31690, 488793, 31689). In summary, this variant meets criteria to be classified as pathogenic for pontocerebellar hypoplasia in an autosomal recessive manner based on the predicted impact of the variant and multiple occurrences with reported pathogenic EXOSC3 variants in individuals with the disease. ACMG/AMP Criteria applied: PM2, PP3, PM3_VeryStrong, PP1_Moderate (Richards 2015). -
The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.041%). Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.91 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.85 (>=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: VCV000031688 /PMID: 22544365 /3billion dataset). The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 22544365, 24524299). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID: 22544365). A different missense change at the same codon (p.Asp132Tyr) has been reported to be associated with EXOSC3 related disorder (PMID: 34582790). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
not provided Pathogenic:9
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In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23284067, 8147499, 22544365, 24524299, 23564332, 27777260, 25533962, 28687512, 11110791, 25326635, 30950035, 31692161, 30986545, 23975261, 31130284, 31980526, 33462000, 32645003, 31589614, 33163565, 33144682) -
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EXOSC3: PM3:Very Strong, PP1:Strong, PM2 -
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Congenital pontocerebellar hypoplasia type 1 Pathogenic:1
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EXOSC3-related disorder Pathogenic:1
The EXOSC3 c.395A>C variant is predicted to result in the amino acid substitution p.Asp132Ala. This variant has been reported as causative for pontocerebellar hypoplasia in both the homozygous and compound heterozygous states (Wan et al. 2012. PubMed ID: 22544365; Eggens et al. 2014. PubMed ID: 24524299; Fasken et al. 2017. PubMed ID: 27777260). This variant is reported in 0.073% of alleles in individuals of European (Non-Finnish) descent in gnomAD. This variant is interpreted as pathogenic. -
Inborn genetic diseases Pathogenic:1
The c.395A>C (p.D132A) alteration is located in exon 2 (coding exon 2) of the EXOSC3 gene. This alteration results from an A to C substitution at nucleotide position 395, causing the aspartic acid (D) at amino acid position 132 to be replaced by an alanine (A). Based on data from the Genome Aggregation Database (gnomAD), the EXOSC3 c.395A>C alteration was observed in 0.04% (115/282766) of total alleles studied, with a frequency of 0.07% (94/129130) in the European (non-Finnish) subpopulation. The c.395A>C (p.D132A) alteration is the most common cause of EXOSC3-related pontocerebellar hypoplasia. This mutation has been reported in multiple affected individuals in the homozygous or compound heterozygous state (Wan, 2012; Biancheri, 2013; Eggens, 2014). The p.D132A alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -
See cases Pathogenic:1
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Hypotonia Pathogenic:1
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Abnormality of the nervous system Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at