1. Department of Pediatrics
2. Imperial College and Royal Brompton Hospital, London, United Kingdom
3. Laboratory of Molecular Genetics, and
4. Electron Microscopy Unit, University Hospital of Ancona, Ancona, Italy; and
5. Department of Clinical and Experimental Medicine, University Hospital of Pisa, Pisa, Italy
6. Department of Pediatrics, University Hospital of Verona, Verona, Italy