Prospective newborn screening (NBS) is among the most successful public health initiatives. Application of tandem mass spectrometry propelled the modern era of NBS which was supplemented by molecular genetic follow-up of screen positives. As natural history and disease mechanisms are determined for other disorders, it is apparent that NBS is poised for further expansion. The neuromuscular disorders spinal muscular atrophy (SMA) and Duchenne and Becker muscular dystrophy (DMD/BMD) are disorders for which NBS is now indicated. We put forth these Specific Aims to establish NBS for SMA and DMD/BMD: