rs202247823
Variant summary
Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM2PP5_Very_Strong
The NM_000532.5(PCCB):c.1606A>G(p.Asn536Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000052 in 1,614,062 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_000532.5 missense
Scores
Clinical Significance
Conservation
Genome browser will be placed here
ACMG classification
Verdict is Pathogenic. Variant got 10 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000145 AC: 22AN: 152224Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000199 AC: 5AN: 251308Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135818
GnomAD4 exome AF: 0.0000424 AC: 62AN: 1461838Hom.: 0 Cov.: 31 AF XY: 0.0000330 AC XY: 24AN XY: 727226
GnomAD4 genome AF: 0.000145 AC: 22AN: 152224Hom.: 0 Cov.: 32 AF XY: 0.000148 AC XY: 11AN XY: 74368
ClinVar
Submissions by phenotype
Propionic acidemia Pathogenic:8Other:1
The PCCB c.1606A>G (p.Asn536Asp) missense variant, also referred to as c.1666A>G (p.Asn556Asp), was reported in one homozygote and five compound heterozygotes with propionic acidemia (Gravel et al. 1994, Pérez-Cerdá et al. 2003, Kraus J et al. 2012). Control data are unavailable for this variant, which is reported at a frequency of 0.000047 in the European (non-Finnish) population of the Genome Aggregation Database. Pérez-Cerdá et al. (2003) demonstrated the p.Asn556Asp variant exhibited propionyl-CoA carboxylase activity at 80% of wild type in transfected fibroblast cell lines but stable protein production by northern and western blot analysis, which is consistent with the mild phenotype reported in observed probands. Based on the evidence the p.Asn556Asp variant is classified as pathogenic for propionic acidemia. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
This sequence change replaces asparagine, which is neutral and polar, with aspartic acid, which is acidic and polar, at codon 536 of the PCCB protein (p.Asn536Asp). This variant is present in population databases (rs202247823, gnomAD 0.005%). This missense change has been observed in individuals with propionic acidemia (PMID: 12757933, 12888983, 22033733, 23053474, 28649556, 30013935). ClinVar contains an entry for this variant (Variation ID: 38881). 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) has been performed 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 PCCB protein function. Experimental studies have shown that this missense change affects PCCB function (PMID: 11136555, 12007220, 12757933, 22033733, 23053474). For these reasons, this variant has been classified as Pathogenic. -
- -
Variant summary: PCCB c.1606A>G (p.Asn536Asp) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.2e-05 in 277058 control chromosomes. This frequency is not higher than expected for a pathogenic variant in PCCB causing Propionic Acidemia (2.2e-05 vs 0.0025), allowing no conclusion about variant significance. The c.1606A>G variant has been reported in the literature in multiple individuals affected with Propionic Acidemia (Gravel 1994, Perez-Cerda 2003, Kraus 2012). These data indicate that the variant is very likely to be associated with disease. Functional studies also reported experimental evidence that the variant has an impact on protein function. The most pronounced variant effect results in <10% of normal activity (Gravel 1994, Perez-Cerda 2003, Kraus 2012). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as pathogenic. -
- -
The missense variant c.1606A>G (p.Asn536Asp) in PCCB gene has been observed in homozygous state in multiple individuals with propionic acidemia (Wenger et. al., 2020; Scott Schwoerer et. al., 2018). Experimental studies have shown that this missense change affects PCCB function (Gallego-Villaret. et. al., 2013). The p.Asn536Asp variant is present with allele frequency of 0.002% in gnomAD exomes database. This variant has been submitted to the ClinVar database as Pathogenic (multiple submitters). Multiple lines of computational evidence (Polyphen - probably damaging, SIFT - damaging and MutationTaster - disease causing) predict a damaging effect on protein structure and function for this variant. The reference amino acid at this position on PCCB gene is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Asn at position 536 is changed to a Asp changing protein sequence and it might alter its composition and physico-chemical properties. For these reasons, this variant has been classified as Pathogenic. The above variant in PCCB gene has also been detected in homozygous state in brother. -
- -
- -
- -
not provided Pathogenic:1
- -
PCCB-related disorder Pathogenic:1
The PCCB c.1606A>G variant is predicted to result in the amino acid substitution p.Asn536Asp. This variant has been commonly reported to be causative for propionic acidemia (Gravel et al. 1994. PubMed ID: 8023851; Kraus et al. 2012. PubMed ID: 22033733; Schwoerer et al. 2018. PubMed ID: 30013935; Stanescu et al. 2021. PubMed ID: 33473339). In vitro studies have shown that the p.Asn536Asp substitution results in a PCC enzyme with moderate residual activity, which is consistent with the finding that the c.1606A>G variant is often associated with a milder phenotype (Pérez-Cerdá et al. 2003. PubMed ID: 12757933). Although the p.Asn563 amino acid is located in the C-terminus of the PCCB protein only three amino acids from the protein termination codon, studies have shown that the p.Asn536Asp substitution affects protein subunit association (Muro et al. 2001. PubMed ID: 11749052; Desviat et al. 2004. PubMed ID: 15464417). This variant is reported in 0.0054% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Taken together, this variant is interpreted as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at