Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PP3_StrongPP5
The NM_001377299.1(NDUFS2):c.683G>A(p.Arg228Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,832 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R228W) has been classified as Uncertain significance.
NDUFS2 (HGNC:7708): (NADH:ubiquinone oxidoreductase core subunit S2) The protein encoded by this gene is a core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (complex I). Mammalian mitochondrial complex I is composed of at least 43 different subunits, 7 of which are encoded by the mitochondrial genome, and the rest are the products of nuclear genes. The iron-sulfur protein fraction of complex I is made up of 7 subunits, including this gene product. Complex I catalyzes the NADH oxidation with concomitant ubiquinone reduction and proton ejection out of the mitochondria. Mutations in this gene are associated with mitochondrial complex I deficiency. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Oct 2009]
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.986
PP5
Variant 1-161209912-G-A is Pathogenic according to our data. Variant chr1-161209912-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 6709.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Uncertain_significance=1}.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 228 of the NDUFS2 protein (p.Arg228Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with isolated complex I deficiency (PMID: 11220739). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 6709). 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 NDUFS2 protein function with a positive predictive value of 80%. 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. -
May 29, 2019
Revvity Omics, Revvity
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
- -
Mitochondrial complex 1 deficiency, nuclear type 6 Pathogenic:1