rs863224150

chrX-19353169-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000284.4(PDHA1):c.506C>T(p.Ala169Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. A169A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 23)
• Consequence: PDHA1 NM_000284.4 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 7.51

Genes affected

PDHA1 (HGNC:8806): (pyruvate dehydrogenase E1 subunit alpha 1) The pyruvate dehydrogenase (PDH) complex is a nuclear-encoded mitochondrial multienzyme complex that catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and provides the primary link between glycolysis and the tricarboxylic acid (TCA) cycle. The PDH complex is composed of multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and lipoamide dehydrogenase (E3). The E1 enzyme is a heterotetramer of two alpha and two beta subunits. This gene encodes the E1 alpha 1 subunit containing the E1 active site, and plays a key role in the function of the PDH complex. Mutations in this gene are associated with pyruvate dehydrogenase E1-alpha deficiency and X-linked Leigh syndrome. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000284.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant X-19353169-C-T is Pathogenic according to our data. Variant chrX-19353169-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 214941.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PDHA1	NM_000284.4	c.506C>T	p.Ala169Val	missense_variant	5/11	ENST00000422285.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PDHA1	ENST00000422285.7	c.506C>T	p.Ala169Val	missense_variant	5/11	1	NM_000284.4	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Pyruvate dehydrogenase E1-alpha deficiency Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 13, 2018	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has been reported in several individuals affected with PDHA1-related disease, and found to be de novo in one of these cases (PMID: 20002461, 21914562, Invitae). ClinVar contains an entry for this variant (Variation ID: 214941). This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with valine at codon 169 of the PDHA1 protein (p.Ala169Val). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and valine. -
Pathogenic, criteria provided, single submitter	clinical testing	Equipe Genetique des Anomalies du Developpement, Université de Bourgogne	Oct 09, 2023	- -

Pyruvate dehydrogenase complex deficiency Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel, ClinGen

May 06, 2021

The c.506C>T variant in the PDHA1 gene is a missense variant occurring in a hotspot domain (aa position A169, located in α β heterodimer interface (PM1). This variant is absent from population databases (PM2). This variant has been reported in three individuals in the literature with presentations consistent with PDHA1-related disease. These three cases include two assumed de novo cases (PMID: 20002461 and PMID: 21914562), and one maternity confirmed de novo case via exome sequencing in PMID: 31683770 (PS2). PMID: 20002461 Western Blot studies showed reduced E1a, and Imbard et al 2011 PDC studies indicate activity <3rd percentile in fibroblasts (PP4). In silico predictors suggest a deleterious effect (REVEL score – 0.946; PP3). In summary, this variant meets criteria to be classified as a pathogenic of PDHA1- related pyruvate dehydrogenase deficiency in an X-linked manner. PDHA1-specific ACMG/AMP criteria applied: (PM1, PM2, PS2, PP3, PP4). This was reviewed with the PDHA1 expert panel on 4/6/2021 and approved on 4/6/2021. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 14, 2021

Not observed in large population cohorts (Lek et al., 2016); Missense variants in this gene are often considered pathogenic (Stenson et al., 2014); In silico analysis supports that this variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 25525159, 20002461, 29445841, 21914562, 31683770) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.71	D
BayesDel_noAF	Pathogenic	0.79
Cadd	Pathogenic	26
Dann	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.6	H;.;.;H;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-3.9	D;D;D;D;D;D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D;D;D;D;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D;D
Polyphen		1.0	.;.;.;D;.;.
Vest4		0.66
MutPred		0.95		Loss of helix (P = 0.1299);.;.;Loss of helix (P = 0.1299);.;Loss of helix (P = 0.1299);
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.97
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs863224150; hg19: chrX-19371287; COSMIC: COSV63327911; COSMIC: COSV63327911;