rs775563122

Positions:

• chr3-136328761-G-A
• chr3-136328761-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000532.5(PCCB):​c.1402G>A​(p.Ala468Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000753 in 1,460,770 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A468S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: PCCB NM_000532.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 8.60

Genes affected

PCCB (HGNC:8654): (propionyl-CoA carboxylase subunit beta) The protein encoded by this gene is a subunit of the propionyl-CoA carboxylase (PCC) enzyme, which is involved in the catabolism of propionyl-CoA. PCC is a mitochondrial enzyme that probably acts as a dodecamer of six alpha subunits and six beta subunits. This gene encodes the beta subunit of PCC. Defects in this gene are a cause of propionic acidemia type II (PA-2). 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 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PCCB	NM_000532.5	c.1402G>A	p.Ala468Thr	missense_variant	14/15	ENST00000251654.9
PCCB	NM_001178014.2	c.1462G>A	p.Ala488Thr	missense_variant	15/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PCCB	ENST00000251654.9	c.1402G>A	p.Ala468Thr	missense_variant	14/15	1	NM_000532.5	P2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251050 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135642

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000753 AC: 11 AN: 1460770 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726816

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000101

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Propionic acidemia Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Mar 07, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 27, 2017	The PCCB c.1402G>A (p.Ala468Thr) missense variant has been identified in a compound heterozygous state in one individual with mild propionic acidemia (Yorifuji et al. 2002). Control data are unavailable for this variant, which is reported at a frequency of 0.00002 in the European (non-Finnish) population of the Exome Aggregation Consortium, but this is based on one allele in a region of good sequence coverage so the variant is presumed to be rare. When analyzed in vivo, the p.Ala468Thr variant was found to have 5.49% of wildtype PCC activity. The evidence for this variant is limited. The p.Ala468Thr variant is therefore classified as a variant of unknown significance but suspicious for pathogenicity for propionic acidemia. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D;.;.;D;D;D;.;.;.
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-3.7	D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D;D;D;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D;D;D
Polyphen		0.98	D;.;.;.;.;.;.;D;.
Vest4		0.97
MutPred		0.96		Loss of ubiquitination at K466 (P = 0.0853);.;.;.;.;.;.;Loss of ubiquitination at K466 (P = 0.0853);.;
MVP		0.93
MPC		0.50
ClinPred		1.0	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.91
gMVP		0.88

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: rs775563122; hg19: chr3-136047603; COSMIC: COSV52443953; COSMIC: COSV52443953;