Intelligent Ratio: A New Method for Carrier and Newborn Screening in Spinal Muscular Atrophy

Genet Test Mol Biomarkers. 2020 Sep;24(9):569-577. doi: 10.1089/gtmb.2020.0085. Epub 2020 Jul 24.

Abstract

Aim: Spinal muscular atrophy (SMA) is an inherited, autosomal recessive neuromuscular disease that causes high morbidity and mortality. The prevalence is 1-2/100,000, while the incidence is 1/6000-1/10,000 among live births. Due to the high carrier frequency (1/40-1/60) of SMA-associated alleles, screening can prevent new cases. The aim of the current study was to present the development of a new, quantitative, real-time, polymerase chain reaction (PCR)-based screening test that uses an intelligent ratio (IR) for analyses, as well as a comparison of the results with the gold standard. Materials and Methods: Included in the study were 100 patients with various risk genotypes for survivor motor neuron 1 (SMN1) and SMN2 genes whose genetics had been previously investigated using multiplex ligation probe amplification (MLPA). A combination of the 5' nuclease assay and allele-specific PCR was used to quantify the SMN1 deletion mutation with real-time PCR using the FII gene as a reference. All of the optimized standards were adapted to software that provided automated analyses. The approval number of the institutional ethics committee for the study is 2012-KAEK-15/1497. Results: The results of the screening test were completely compatible with the MLPA results; it achieved 100% sensitivity and specificity compared with the gold standard. The use of the IR in the analyses provided a user-independent method that quickly and accurately provided results, regardless of the amount of DNA used of the extraction method. Conclusion: Carrier or newborn screening of SMA is essential in countries that have high rates of consanguineous marriages. The screening test presented in this study that uses FII as a reference gene proved to be low-cost, reliable, applicable, accurate, and amenable to use in an automated system for SMA screening.

Keywords: carrier screenig; new kit; newborn screening; spinal muscular atrophy.

MeSH terms

  • Alleles
  • DNA Primers / genetics
  • Female
  • Humans
  • Infant, Newborn
  • Male
  • Muscular Atrophy, Spinal / diagnosis*
  • Muscular Atrophy, Spinal / genetics
  • Neonatal Screening / methods*
  • Real-Time Polymerase Chain Reaction / methods
  • Sensitivity and Specificity
  • Survival of Motor Neuron 1 Protein / genetics*
  • Survival of Motor Neuron 1 Protein / metabolism
  • Turkey

Substances

  • DNA Primers
  • SMN1 protein, human
  • Survival of Motor Neuron 1 Protein