rs879253805

Positions:

• chr13-100268747-A-G
• chr13-100268747-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_000282.4(PCCA):​c.878A>G​(p.Gln293Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000547 in 1,461,748 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: PCCA NM_000282.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 9.31

Genes affected

PCCA (HGNC:8653): (propionyl-CoA carboxylase subunit alpha) The protein encoded by this gene is the alpha subunit of the heterodimeric mitochondrial enzyme Propionyl-CoA carboxylase. PCCA encodes the biotin-binding region of this enzyme. Mutations in either PCCA or PCCB (encoding the beta subunit) lead to an enzyme deficiency resulting in propionic acidemia. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, May 2010]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a domain ATP-grasp (size 197) in uniprot entity PCCA_HUMAN there are 6 pathogenic changes around while only 1 benign (86%) in NM_000282.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 13-100268747-A-G is Pathogenic according to our data. Variant chr13-100268747-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 218252.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PCCA	NM_000282.4	c.878A>G	p.Gln293Arg	missense_variant	11/24	ENST00000376285.6	NP_000273.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PCCA	ENST00000376285.6	c.878A>G	p.Gln293Arg	missense_variant	11/24	1	NM_000282.4	ENSP00000365462	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461748 Hom.: 0 Cov.: 30 AF XY: 0.00000688 AC XY: 5 AN XY: 727188

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000812

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Propionic acidemia Pathogenic:2

Pathogenic, criteria provided, single submitter	research	Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital	Jan 01, 2013	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 22, 2023	ClinVar contains an entry for this variant (Variation ID: 218252). 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 expected to disrupt PCCA protein function. This variant disrupts the p.Gln293 amino acid residue in PCCA. Other variant(s) that disrupt this residue have been observed in individuals with PCCA-related conditions (PMID: 15164333, 23430860, 27227689), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. This missense change has been observed in individual(s) with propionic acidemia (PMID: 23430860, 27227689; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 293 of the PCCA protein (p.Gln293Arg). -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jul 20, 2022

Variant summary: PCCA c.878A>G (p.Gln293Arg) results in a conservative amino acid change located in the Carbamoyl-phosphate synthetase large subunit-like, ATP-binding domain (IPR005479) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251330 control chromosomes (gnomAD). c.878A>G has been reported in the literature in individuals affected with Propionic Acidemia, including one homozygote (Lvesque_2011, Gupta_2016). These data indicate that the variant may be associated with disease. Additionally, another variant (p.Gln293Glu) that disrupts the same residue has been found in one individual affected with Propionic Academia, suggesting this residue is clinical important (PMID: 15164333). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One ClinVar submitter (evaluation after 2014) cites the variant as pathogenic. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 25, 2021

The c.878A>G (p.Q293R) alteration is located in exon 11 (coding exon 11) of the PCCA gene. This alteration results from a A to G substitution at nucleotide position 878, causing the glutamine (Q) at amino acid position 293 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	.;.;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	5.0	.;H;H
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.7	D;D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.91
MutPred		0.93		.;Gain of MoRF binding (P = 0.0221);Gain of MoRF binding (P = 0.0221);
MVP		0.99
MPC		0.64
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.97
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs879253805; hg19: chr13-100921001;