8-95045599-G-C
Variant summary
Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3PP5
The NM_152416.4(NDUFAF6):āc.532G>Cā(p.Ala178Pro) variant causes a missense change. The variant allele was found at a frequency of 0.0000992 in 1,613,410 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).
Frequency
Consequence
NM_152416.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000394 AC: 6AN: 152170Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000112 AC: 28AN: 249340Hom.: 0 AF XY: 0.000148 AC XY: 20AN XY: 135280
GnomAD4 exome AF: 0.000105 AC: 154AN: 1461240Hom.: 0 Cov.: 30 AF XY: 0.000116 AC XY: 84AN XY: 726962
GnomAD4 genome AF: 0.0000394 AC: 6AN: 152170Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74324
ClinVar
Submissions by phenotype
Mitochondrial complex 1 deficiency, nuclear type 17 Pathogenic:5
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The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.010%). Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.73 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.72 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000372254 /PMID: 27623250). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID: 29531337). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -
The missense variant p.A178P in NDUFAF6 (NM_152416.4) has been reported in an affected patient in compound heterozygous state with a deep intronic variant (Bianciardi L et al).Functional studies revealed a damaging effect. The variant has been submitted to ClinVar as Pathogenic. The p.A178P missense variant is predicted to be damaging by both SIFT and PolyPhen2. The nucleotide c.532 in NDUFAF6 is predicted conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Pathogenic -
Variant summary: C8orf38 c.532G>C (p.Ala178Pro) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0001 in 280728 control chromosomes. c.532G>C has been reported in the literature in trans along with a pathogenic intronic variant in multiple individuals affected with Leigh syndrome (example, Bianciardi_2016, Catania_2018). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in significantly reduced normal complex I activity in patients fibroblasts, which was rescued by normal C8ORF38 (Bianciardi_2016). The following publications have been ascertained in the context of this evaluation (PMID: 27623250, 29531337). ClinVar contains an entry for this variant (Variation ID: 372254). Based on the evidence outlined above, the variant was classified as pathogenic. -
Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Mitochondrial complex I deficiency, nuclear type 17 (MIM#618239). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to proline. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2: 29 heterozygotes, 0 homozygotes). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated SQS_PSY domain (PDB, DECIPHER, NCBI). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0802 - This variant has moderate previous evidence of pathogenicity in unrelated individuals. Three unrelated probands with Leigh syndrome have been reported to be compound heterozygotes with this variant (PMID: 29531337). (SP) 0903 - This variant has insufficient evidence for segregation with disease. A single family with two affected siblings has been reported (PMID: 29531337). (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
not provided Pathogenic:1Uncertain:1
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 34426522, 31589614, 27623250, 33097395, 29531337) -
This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 178 of the NDUFAF6 protein (p.Ala178Pro). This variant is present in population databases (rs201088736, gnomAD 0.02%). This missense change has been observed in individual(s) with clinical features of complex 1 deficiency and/or complex 1 deficiency (PMID: 29531337). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 372254). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt NDUFAF6 protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -
Inborn genetic diseases Uncertain:1
The c.532G>C (p.A178P) alteration is located in exon 5 (coding exon 5) of the NDUFAF6 gene. This alteration results from a G to C substitution at nucleotide position 532, causing the alanine (A) at amino acid position 178 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
See cases Uncertain:1
ACMG classification criteria: PM2, PP3, PP5 -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at