<unk>  is a rare pervasive developmental disorder that primarily affects the nervous system. Individuals with<unk>  typically do not have any symptoms at birth, but between the ages of about 6 and 18 months they begin to experience delays in acquiring new motor and intellectual skills, such as crawling or beginning to speak. Eventually they lose previously acquired skills.
Infantile neuroaxonal dystrophy
Ullrich congenital muscular dystrophy
Congenital muscular dystrophy
Spinal muscular atrophy
Myotonic dystrophy
Madras motor neuron disease
Distal spinal muscular atrophy type 1
Distal spinal muscular atrophy type 2