The c.1375dup (p.Arg459ProfsTer4) variant in ACADVL is a frameshift variant predicted to cause a premature stop codon in biologically-relevant-exon14/20 leading to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1; PMIDs 9973285, 11590124). At least one individual with this variant was identified by newborn screen, but this information is insufficient for to use toward classification (PMID: 26385305). The highest population minor allele frequency in gnomAD v2.1.1 is 0.000008794 in the European (non-Finnish) population, which is lower than the ClinGen ACADVL Variant Curation Expert Panel threshold (<0.001) for PM2_Supporting, meeting this criterion (PM2_Supporting). In summary, this variant meets the criteria to be classified as likely pathogenic for autosomal recessive VLCAD deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen ACADVL Variant Curation Expert Panel: PVS1, PM2_Supporting (VCEP specifications version1; approved November 8, 2021)