rs780406346

chr13-100209385-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000282.4(PCCA):c.522G>A(p.Met174Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000044 in 1,612,970 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 Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000047 (0 hom.)
• Consequence: PCCA NM_000282.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 9.75

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 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000282.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.944

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PCCA	NM_000282.4	c.522G>A	p.Met174Ile	missense_variant	7/24	ENST00000376285.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PCCA	ENST00000376285.6	c.522G>A	p.Met174Ile	missense_variant	7/24	1	NM_000282.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152142 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000438 AC: 11 AN: 251396 Hom.: 0 AF XY: 0.0000662 AC XY: 9 AN XY: 135860

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000792

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000472 AC: 69 AN: 1460828 Hom.: 0 Cov.: 30 AF XY: 0.0000495 AC XY: 36 AN XY: 726800

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000522

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152142 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74298

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000130 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000412 AC: 5

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.000218

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Propionic acidemia Uncertain:4

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Sep 06, 2022	This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 174 of the PCCA protein (p.Met174Ile). This variant is present in population databases (rs780406346, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with PCCA-related conditions. ClinVar contains an entry for this variant (Variation ID: 310844). 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. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 29, 2024	- -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 19, 2021

The c.522G>A (p.M174I) alteration is located in exon 7 (coding exon 7) of the PCCA gene. This alteration results from a G to A substitution at nucleotide position 522, causing the methionine (M) at amino acid position 174 to be replaced by an isoleucine (I). The in silico prediction for the p.M174I alteration is inconclusive. 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	0.96
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Pathogenic	0.29
Cadd	Pathogenic	26
Dann	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-3.6	D;D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0010	D;D;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		0.98	D;.;P
Vest4		0.83
MutPred		0.78		.;Loss of ubiquitination at K177 (P = 0.0417);Loss of ubiquitination at K177 (P = 0.0417);
MVP		0.95
MPC		0.59
ClinPred		0.94	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.94

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: rs780406346; hg19: chr13-100861639;