11-34984675-A-G
Variant summary
Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBS1_Supporting
The NM_003477.3(PDHX):c.1129A>G(p.Ile377Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000277 in 1,614,092 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_003477.3 missense
Scores
Clinical Significance
Conservation
Publications
- Leigh syndromeInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- pyruvate dehydrogenase E3-binding protein deficiencyInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Likely_benign. The variant received -3 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| PDHX | NM_003477.3 | c.1129A>G | p.Ile377Val | missense_variant | Exon 9 of 11 | ENST00000227868.9 | NP_003468.2 | |
| PDHX | NM_001135024.2 | c.949A>G | p.Ile317Val | missense_variant | Exon 9 of 11 | NP_001128496.2 | ||
| PDHX | NM_001166158.2 | c.448A>G | p.Ile150Val | missense_variant | Exon 4 of 6 | NP_001159630.1 | ||
| PDHX | XM_011520390.2 | c.949A>G | p.Ile317Val | missense_variant | Exon 9 of 11 | XP_011518692.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| PDHX | ENST00000227868.9 | c.1129A>G | p.Ile377Val | missense_variant | Exon 9 of 11 | 1 | NM_003477.3 | ENSP00000227868.4 |
Frequencies
GnomAD3 genomes AF: 0.000177 AC: 27AN: 152220Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000676 AC: 17AN: 251338 AF XY: 0.0000663 show subpopulations
GnomAD4 exome AF: 0.000287 AC: 420AN: 1461754Hom.: 0 Cov.: 31 AF XY: 0.000298 AC XY: 217AN XY: 727186 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000177 AC: 27AN: 152338Hom.: 0 Cov.: 32 AF XY: 0.000148 AC XY: 11AN XY: 74490 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:3
The I377V variant in the PDHX gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The I377V variant was not observed at any significant frequency in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The I377V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position where amino acids with similar properties to Isoleucine are tolerated across species. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. We interpret I377V as a variant of uncertain significance.
This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 377 of the PDHX protein (p.Ile377Val). This variant is present in population databases (rs75430333, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with PDHX-related conditions. ClinVar contains an entry for this variant (Variation ID: 214958). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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.
Pyruvate dehydrogenase E3-binding protein deficiency Uncertain:2
Likely pathogenicity based on finding it once in our laboratory homozygous in a 1-year-old male with regression, progressive encephalopathy, hypotonia, abnormal breathing requiring ventilation, a deceased older sister (not tested) with a similar presentation. However, lactic acidosis was not noted. Heterozygotes would be expected to be asymptomatic carriers.
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.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at