Efficacy, Safety and Tolerability of AFQ056 in Fragile X Patients

Inclusion Criteria: * Male, non-smoking patients between 18 and 35 years of age (both inclusive). * Patients with fmr1 full mutation (\> 200 CGG repeats) * Patients with a Clinical Global Impression Severity Score (CGI-S) of \> 4 (moderately ill) * Patients with a score of \>20 in the ABC-C scale (at screening) * Patients with a mental age of ≥ 48 months as measured by the Stanford-Binet test Exclusion Criteria: * Patients with DSM-IV diagnosis of schizophrenia, history and/or presence of psychosis, confusional states and/or repeated hallucinations. * Patients with a history of seizures in the past 5 years without any therapeutic treatment controlling the disorders. * Patients under stable anti-convulsant therapies that experienced seizures in the 2 years prior to randomization * Patients with ECG abnormalities, autonomic dysfunctions, bronchospastic diseases, drug or atopic allergy * Any surgical or medical condition which might significantly alter the absorption, distribution, metabolism or excretion of drugs * Patients using (or have used within four weeks before randomization) concomitant medications that are potent inhibitors of CYP3A4 (e.g., ketoconazole, ritonavir, etc.) Other protocol-defined inclusion/exclusion criteria may apply.