Smith-Magenis syndrome (SMS) is characterized by distinctive facial features, developmental delay, cognitive impairment and behavioural abnormalities. The facial appearance shows midfacial hypoplasia, relative prognathism, and heavy brows with a "pugilistic" appearance (Greenberg et al. 1991; Potocki et al., 2003). The behavioural phenotype includes sleep disturbance, stereotypes, inattention, hyperactivity, maladaptive behaviours including frequent outbursts/temper tantrums, impulsivity, distractibility, aggression and self-injurious behaviours including self-hitting, self-biting, and/or skin picking, inserting foreign objects into body orifices (polyembolokoilamania), and yanking fingernails and/or toenails (onychotillomania) (De Leernsyder et al. 2001; Smith, Dykens & Greenberg, 1998a, 1998b). The diagnosis of Smith-Magenis syndrome is based on clinical findings and confirmed by detection of an interstitial deletion of 17p11.2 by G-banded cytogenetic analysis and/or by fluorescence in situ hybridization (FISH). Probes for FISH testing must include the RAI1 gene which is the only gene known to account for the majority of features in Smith-Magenis syndrome. Autism Spectrum Disorders (ASDs) type behaviours have been reported in many cases, but not been extensively studied with objective and standardized diagnostic tools.
Objectives: The first goal of this study is to describe ASDs behaviours in patients exhibiting the Smith- Magenis Syndrome, using reliable, objective assessment tools.
Methods: To achieve this aim we examined 5 participants with Smith- Magenis Syndrome (SMS), between the ages of 11 and 35 years (3 males and 2 females; av. chron. age 24.5 s.d. 9.5). Each subject was evaluated using the Autistim Diagnostic Observation Schedule (ADOS) and the Leiter-R scale. The parents completed the Autism Diagnostic Interview – Revised (ADI-R) and the
Results: All subjects were functioning considerably below average (I.Q. av. score 38.8 ; s.d. 11.6) with IQ scores ranging from 30 to 57. Based on VABS, subjects in our sample were functioning significantly below average in all domains of adaptive functioning: Communication (mean 9.8 s.d. 30), Socialization (mean 74.2 s.d. 42.6) and Daily Living Skills (mean 92.6 s.d. 22.8). Scores on Communication, Socialization, Daily Living Skills scales were not significantly related to IQ. On the ADI-R interview two subjects were above autism cut-off in two domains (Verbal Communication av. score 9.5 s.d. 2.1 and Non Verbal Communication av. score 7 s.d. 1.4; Social Reciprocal Interaction av. score 11.5 s.d. 7.7). On ADOS test the same subjects were above autism cut-off (Communication and Language av. score 3; Social Reciprocal Interaction av. score 10 s.d. 4.2).
Conclusions: This study provide a description of ASD symptoms in subjects with SMS based on objective, validated assessment techniques. Data from the current study indicate that 2 of the 5 subjects with Smith-Magenis Syndrome show symptoms of Autism Spectrum Disorder. These results might be used to drive more effective and individualised intervention in subjects with SMS.