Targeted next generation sequencing for newborn screening of Menkes disease

Abstract

Purpose: Population-based newborn screening (NBS) allows early detection and treatment of inherited disorders. For certain medically-actionable conditions, however, NBS is limited by the absence of reliable biochemical signatures amenable to detection by current platforms. We sought to assess the analytic validity of an ATP7A targeted next generation DNA sequencing assay as a potential newborn screen for one such disorder, Menkes disease. Methods: Dried blood spots from control or Menkes disease subjects (n = 22) were blindly analyzed for pathogenic variants in the copper transport gene, ATP7A. The analytical method was optimized to minimize cost and provide rapid turnaround time. Results: The algorithm correctly identified pathogenic ATP7A variants, including missense, nonsense, small insertions/deletions, and large copy number variants, in 21/22 (95.5%) of subjects, one of whom had inconclusive diagnostic sequencing previously. For one false negative that also had not been detected by commercial molecular laboratories, we identified a deep intronic variant that impaired ATP7A mRNA splicing. Conclusions: Our results support proof-of-concept that primary DNA-based NBS would accurately detect Menkes disease, a disorder that fulfills Wilson and Jungner screening criteria and for which biochemical NBS is unavailable. Targeted next generation sequencing for NBS would enable improved Menkes disease clinical outcomes, establish a platform for early identification of other unscreened disorders, and complement current NBS by providing immediate data for molecular confirmation of numerous biochemically screened conditions.

Keywords

• Menkes disease
• ATP7A
• Molecular genetics
• Targeted next generation sequencing
• Dried blood spots
• Newborn screening