Distinctive Pattern of Behavioral Functioning in Angelman Syndrome

Abstract

Angelman syndrome is a neurogenetic disorder that is characterized by impairments in neurological, motor, and intellectual functioning. This study compared 27 participants with Angelman syndrome to clinical and community participants with developmental disabilities of mixed etiology to determine whether Angelman syndrome is associated with a distinctive pattern of behavioral functioning. The groups with and without Angelman syndrome were matched on chronological age, gender, and level of intellectual functioning. The dependent measure was parent ratings of maladaptive behavior using the Aberrant Behavior Checklist. The Angelman syndrome group had significantly lower scores on measures of irritability and lethargy. Results contribute to the delineation of a behavior phenotype for the syndrome.

The behavioural phenotype of Angelman syndrome

“…There are four studies that have attempted to systematically measure the behaviours of people with Angelman syndrome, using four different questionnaires (Summers et al, 1995;Summers & Feldman, 1999;Clarke & Marston, 2000;Walz & Benson, 2002). In order to further consider the notion of a behavioural phenotype for Angelman syndrome, these four studies will be briefly described and critically examined.…”

“…In both Summers and Feldman's (1999) and Walz and Benson's (2002) studies, it was not explored whether different phenotypic differences occurred across genetic sub types. Smith, Wiles, Haan, McGill, Wallace, Dixon, Selby, Golley, Marks, and Trent (1996) suggested that there is a distinct phenotype associated with a deletional Angelman syndrome consisting of: intellectual disability, ataxia, lack of speech, happy disposition and epilepsy.…”

“…Walz and Benson conducted a within-group analysis and did not find that age or gender were significantly correlated with any of the behaviour variables. Although Summers and Feldman (1999) did report the age ranges of the individuals (2-26 years) and the three comparison groups were matched on age, by collapsing the age groups, cohort effects may be operating that may mask important findings. This point is also highlighted in Summers et al's (1995) study.…”

“…The Child Behavior Checklist used by Summers and colleagues (1995) has not been normed on individuals with intellectual disabilities, therefore the sensitivity of the measures in identifying characteristics specific to individuals with intellectual disabilities is unknown (Dykens, 1995). The Aberrant Behavior Checklist used in both Summers and Feldman's (1999) study and Clark and Marston's study (2000), and the Reiss Screen for Maladaptive Behavior used in Clark and Marston's study both share several limitations. Although they have been normed on individuals with intellectual disabilities, the construct validity of the measures have been criticised for being vague, heterogeneous and difficult to interpret (Russell, 2000).…”

“…Although they have been normed on individuals with intellectual disabilities, the construct validity of the measures have been criticised for being vague, heterogeneous and difficult to interpret (Russell, 2000). The authors however do discuss these issues, they concluded that although such measures may identify differences in occurrence of particular behaviours, the topography of the behaviour may vary, for example, aggression in individuals with Angelman syndrome may take the form of grabs or rough hugs but may look different in another diagnostic group (Summers & Feldman, 1999).…”