Spinal Muscular Atrophy Carrier Screening by Multiplex Polymerase Chain Reaction using Dried Blood Spot on Filter Paper

Abstract

Summary Spinal muscular atrophy (SMA) is a common, often fetal, autosomal recessively inherited disease leading to progressive muscle wasting and paralysis as a result of degeneration of anterior horn cells of the spinal cord. The SMA‐determining gene, called the survival of motor neuron gene (SMN), is present on 5q13 in two nearly identical copies, telomeric SMN (SMN1) and centromeric SMN (SMN2). It has been established that SMA is caused by mutations in SMN1 whereas homozygous deletion of SMN2 has apparently no pathological consequences. The aim of this study is to develop an easy and inexpensive method for the isolation of high‐quality template DNA from blood samples for SMA carrier screening by multiplex polymerase chain reaction. We have developed a protocol that optimizes detection of the SMN1 copy number in the human genome, producing a specific and sensitive assay using DNA extracted from a dried blood spot on IsoCode™ paper.

Spinal muscular atrophy carrier frequency in Saudi Arabia

“…Only SMN1 and not SMN2 was quantified in the normal participants because the focus of the study was SMN1 carrier status. The current method, similarly to other methods reported to date (Feldkötter et al, 2002; Martín et al, 2002; Scheffer et al, 2000), does not distinguish between individuals with two SMN1 copies in both chromosomes (genotype 1:1, non‐SMA carrier) and individuals with 2 SMN1 copies in single chromosomes (genotype 0:2, SMA carrier) (Majumdar et al, 2005). The methodology was verified using known positive cases.…”