Our DCNext test includes next generation sequencing (NGS) and deletion/duplication analysis of DKC1, TINF2, TERC, NHP2, NOP10, WRAP53, and TERT. Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized kit and quantified. Sequence enrichment of the targeted coding exons and adjacent intronic nucleotides is carried out by a bait-capture methodology using long biotinylated oligonucleotide probes, followed by polymerase chain reaction (PCR) and next generation sequencing (NGS). 

Additional Sanger sequencing is performed for any regions missing, or with insufficient read depth coverage for reliable heterozygous variant detection. Potentially homozygous variants, variants in regions complicated by pseudogene interference, and variant calls not satisfying depth of coverage and variant allele frequency quality thresholds are verified by Sanger sequencing. This test targets detection of DNA sequence mutations in all coding domains, and well into the 5’ and 3’ ends of all the introns and untranslated regions. Gross deletion/duplication analysis for TERC is performed via multiplex ligation probe amplification (MLPA, MRC Holland). Gross deletion/duplication analysis for all remaining genes is performed utilizing a targeted chromosomal microarray.