1 Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, 95124 Catania, Italy. Electronic address: m.ruggieri@unict.it.
2 Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, 95124 Catania, Italy; Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.
3 Oculista Scuderi, Catania, Italy.
4 Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95124 Catania, Italy.
5 National Centre for Rare Diseases, Istituto Superiore di Sanità, Rome, Italy; Institute of Neurological Sciences, National Research Council, Catania, Italy.