Regarding the primary outcome of psychological and learning capabilities , both studies assessed the effect of interventions on  children 's verbal and non-verbal intellectual functioning using the Wechsler Intelligence Scale for Children - Revised .
AUTHORS ' CONCLUSIONS Low- quality evidence from two small trials showed that when compared to placebo , LAC may not improve intellectual functioning or hyperactive behaviour in children with FXS
BACKGROUND People with fragile X syndrome ( FXS ) have an intellectual dysfunction that can range from very mild to severe .
Symptoms can include speech and language delays and behavioural difficulties such as aggression or self injurious behaviours , emotional lability , and anxiety-related problems ( for example obsessive-compulsive symptoms and perseverative behaviours ) .
In some cases , affected people may have an additional diagnosis of attention deficit hyperactivity disorder or an autism spectrum disorder .
OBJECTIVES To review the efficacy and safety of L-acetylcarnitine in improving the psychological , intellectual , and social performance of people with FXS .
A double‐blind, parallel, multicenter comparison of L‐acetylcarnitine with placebo on the attention deficit hyperactivity disorder in fragile X syndrome boys
Attention deficit hyperactivity disorder ( ADHD ) is a frequent behavioral problem in young boys with fragile X syndrome ( FXS ) , and its treatment is critical for improving social ability . The short‐term efficacy of stimulant medications like methylpheni date ( MPH ) is well established in children with ADHD . FXS boys treated with MPH have improved attention span and socialization skills ; however their mood becomes unstable at higher doses . Therefore , alternative pharmacological treatment of ADHD symptoms is desirable . A recent study showed that carnitine has a beneficial effect on the hyperactive – impulsive behavior in boys with ADHD without side effects . Our previous placebo‐controlled trial indicated that L‐acetylcarnitine ( LAC ) reduces hyperactivity in FXS boys . The objective of this study was to determine the efficacy of LAC in a larger sample of FXS boys with ADHD . The study design was r and omized , double blind placebo controlled , parallel , and multicenter ( with eight centers involved in Italy , France , and Spain ) . Sixty‐three FXS males with ADHD ( aged 6–13 years ) were enrolled ; 7 patients dropped out , 56 completed the one‐year treatment , and 51 were included in the statistical analysis . Both groups improved their behavior , showing that psychosocial intervention has a significant therapeutic effect . However , we observed a stronger reduction of hyperactivity and improvement of social behavior in patients treated with LAC , compared with the placebo group , as determined by the Conners ' Global Index Parents and the Vinel and Adaptive Behavior Scale . Our results show that LAC ( 20–50 mg/kg/day ) represents a safe alternative to the use of stimulant drugs for the treatment of ADHD in FXS children . © 2008 Wiley‐Liss ,
Regarding the primary outcome of psychological and learning capabilities , both studies assessed the effect of interventions on  children 's verbal and non-verbal intellectual functioning using the Wechsler Intelligence Scale for Children - Revised .
AUTHORS ' CONCLUSIONS Low- quality evidence from two small trials showed that when compared to placebo , LAC may not improve intellectual functioning or hyperactive behaviour in children with FXS
BACKGROUND People with fragile X syndrome ( FXS ) have an intellectual dysfunction that can range from very mild to severe .
Symptoms can include speech and language delays and behavioural difficulties such as aggression or self injurious behaviours , emotional lability , and anxiety-related problems ( for example obsessive-compulsive symptoms and perseverative behaviours ) .
In some cases , affected people may have an additional diagnosis of attention deficit hyperactivity disorder or an autism spectrum disorder .
OBJECTIVES To review the efficacy and safety of L-acetylcarnitine in improving the psychological , intellectual , and social performance of people with FXS .