Characterizing Phenothypes in non ambulant Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is an X -linked inherited disorder due to mutations in the gene encoding dystrophin. The absence of dystrophin is responsible for progressive muscle weakness leading to loss of ambulation and progressive impairment of respiratory and cardiac muscles. Most of the recent trials has so far targeted ambulant DMD boys. Less attention has been devoted to non-ambulant patients as they have a much more advanced clinical impairment associated to a much more severe muscle replacement on muscle biopsy. One of the difficulties in targeting non ambulant patients that they constitute a very heterogeneous group ranging from boys who have just lost ambulation, often still having a good strength in the upper limbs and no obvious clinical signs of respiratory and cardiac impairment to young adults with extremely limited mobility, and variable cardiac and respiratory involvement. The aim of our study are: 1. To prospectively collect information on several aspects of function in all the non-ambulant DMD patients followed in our centers by using a structured battery of tests including motor, respiratory and cardiac function. 2. To retrospectively collect similar information on the data collected in the last decade using similar standards of care and, when available, the same measures. 3. To establish the effect of steroids after loss of ambulation on different aspects of function. 4. To use this integrated approach to identify patterns of severity and progression and identify the most appropriate outcome measures and endpoints in each group 5. Establishing genotype/phenotype correlations.