Coexistence of peripheral myelin protein 22 and dystrophin mutations in a chinese boy

We describe a 10-year-old Chinese boy with features of Charcot-Marie-Tooth disease (CMT) and Duchenne muscular dystrophy (DMD).

Case report.

Weakness and mild sensory loss in the distal extremities, pes cavus, and nerve conduction findings suggested demyelinating neuropathy, while moderate calf pseudohypertrophy, proximal muscle weakness, a myopathic pattern on electromyography, and deficiency of dystrophin immunohistochemical staining on muscle biopsy indicated DMD. Genetic testing revealed a large deletion spanning exon 50 in the gene coding for dystrophin and duplications in the gene coding for peripheral myelin protein 22.

This is an interesting and very rare case of CMT type 1A comorbid with DMD. This results in an unusual phenotype and rapid deterioration of motor function. Usage of both target region capture and next generation sequencing is a powerful tool for predicting precisely the range of the large DNA fragment deletion in DMD.