This gene sequencing panel includes both sequencing and deletion/duplication (CNV) analysis for all coding regions of the included genes (unless otherwise noted). All analysis is performed utilizing next-generation sequencing (NGS) technology. All variants are classified according to American College of Genetics and Genomics (ACMG) guidelines.

Elevated C4 is associated with isobutyryl-CoA dehydrogenase deficiency, short-chain acyl-CoA dehydrogenase deficiency, and ethylmalonic encephalopathy. Isobutyryl-CoA dehydrogenase deficiency is a disease that causes an inability to break down the amino acid valine. Most individuals with isobutyryl-CoA dehydrogenase deficiency are asymptomatic, but those who present in childhood can have dilated cardiomyopathy, hypotonia, developmental delay, and anemia. The incidence of isobutyryl-CoA dehydrogenase deficiency is unknown. Short-chain acyl-CoA dehydrogenase deficiency is a disease that prevents the body from burning certain fats. The age of onset is in infancy, and symptoms typically include vomiting, hypoglycemia, lethargy, poor feeding, failure to thrive, hypotonia, seizures, developmental delay, and small head size. The disease can be well managed with a strict diet and avoiding periods of fasting. The incidence of short-chain acyl-CoA dehydrogenase deficiency is estimated to be ~ 1 in 35,000. Ethylmalonic encephalopathy is a disease that impairs energy production in mitochondria. Age of onset is typically in the neonatal period, and symptoms include developmental delay, developmental regression, hypotonia, seizures, abnormal movements, petechiae, acrocyanosis of the hands and feet, and chronic diarrhea. Death usually occurs in early childhood. The incidence of ethylmalonic encephalopathy is unknown.

ACAD8 ACADS, ETHE1,

Sequencing is performed on genomic DNA using an Agilent targeted sequence capture method to enrich for the exome. Direct sequencing of the amplified captured regions was performed using 2X150bp reads on Illumina next generation sequencing (NGS) systems. A base is considered to have sufficient coverage at 20X and an exon is considered fully covered if all coding bases plus three nucleotides of flanking sequence on either side are covered at 20X or more. A list of these regions, if any, is available upon request. Alignment to the human reference genome (GRCh37) is performed and annotated variants are identified in the targeted region. Variants reviewed have a minimum coverage of 8X and an alternate allele frequency of 20% or higher. Indel and single nucleotide variants (SNVs) may be confirmed by Sanger sequence analysis before reporting at director discretion. This assay cannot detect variants in regions of the exome that are not covered, such as deep intronic, promoter and enhancer regions, areas containing large numbers of tandem repeats, and variants in mitochondrial DNA. Copy number variation (CNV) analysis detects deletions and duplications; in some instances, due to the size of the exons, sequence complexity, or other factors, not all CNVs may be analyzed or may be difficult to detect. When reported, copy number variant size is approximate. Actual breakpoint locations may lie outside of the targeted regions. CNV analysis will not detect tandem repeats, balanced alterations (reciprocal translocations, Robertsonian translocations, inversions, and balanced insertions), methylation abnormalities, triploidy, and genomic imbalances in segmentally duplicated regions. This assay is not designed to detect mosaicism; possible cases of mosaicism may be investigated at the discretion of the laboratory director. Primary data analysis is performed using Illumina bcl2fastq converter v2.19. Secondary analysis is performed using Illumina DRAGEN Bio-IT Platform v.3.10.8. Tertiary data analysis is performed using SnpEff v5.0 and Revvity Omics’ internal ODIN v.1.01 software. CNV and absence of heterozygosity are assessed using BioDiscovery’s NxClinical v6.1 software.