ClinVar Genomic variation as it relates to human health

The ACADVL c.1316G>A; p.Gly439Asp variant (rs533055438) is reported in the literature in individuals diagnosed with VLCAD deficiency, who are heterozygous for another ACADVL variant (Gobin-Limballe 2010, Pena 2016, Schiff 2013). Cultured fibroblasts from an individual carrying p.Gly439Asp and p.Met443Arg, showed no detectable VLCAD activity (Schiff 2013). Furthermore, functional analysis of p.Gly439Asp expressed using an in vitro prokaryotic system yielded no activity, even though protein of the correct size was detected by Western blot (Schiff 2013). The p.Gly439Asp variant is reported as pathogenic in ClinVar (Variation ID: 203582), and found in the general population with a low frequency of 0.002% (6/277134 alleles) in the Genome Aggregation Database. The glycine at codon 439 is highly conserved and computational algorithms (SIFT, PolyPhen2, MutationTaster) predict this variant to be deleterious. Based on the above information, this variant is considered pathogenic. REFERENCES Gobin-Limballe S et al. Compared effects of missense mutations in Very-Long-Chain Acyl-CoA Dehydrogenase deficiency: Combined analysis by structural, functional and pharmacological approaches. Biochim Biophys Acta. 2010 May;1802(5):478-84. Pena LD et al. Outcomes and genotype-phenotype correlations in 52 individuals with VLCAD deficiency diagnosed by NBS and enrolled in the IBEM-IS database. Mol Genet Metab. 2016 Aug;118(4):272-81. Schiff M et al. Molecular and cellular pathology of very-long-chain acyl-CoA dehydrogenase deficiency. Mol Genet Metab. 2013 May;109(1):21-7.

The NM_000018.3:c.1316G>A (NP_000009.1:p.Gly439Asp) [GRCH38: NC_000017.11:g.7223859G>A] variant in ACADVL gene is interpretated to be Pathogenic based on ACMG guidelines (PMID: 25741868). This variant has been reported in PMID: 20060901. This variant meets the following evidence codes reported in the ACMG guidelines: PS1, PS3

This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 439 of the ACADVL protein (p.Gly439Asp). This variant is present in population databases (rs533055438, gnomAD 0.005%). This missense change has been observed in individual(s) with very long chain acyl-CoA dehydrogenase deficiency (PMID: 17999356, 23480858; Invitae). ClinVar contains an entry for this variant (Variation ID: 203582). 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 ACADVL protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects ACADVL function (PMID: 23480858). This variant disrupts the p.Gly439 amino acid residue in ACADVL. Other variant(s) that disrupt this residue have been observed in individuals with ACADVL-related conditions (Invitae), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic.

Expression of G439D in E. coli found no detectable enzyme activity compared to wild-type controls (PMID: 23480858); Not observed at significant frequency in large population cohorts (gnomAD); 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: 30925787, 23169530, 27209629, 30194637, 31031081, 20060901, 23480858, 17999356)