Social Behavior and Autism Traits in a Sex Chromosomal Disorder: Klinefelter (47XXY) Syndrome
Sophie van Rijn
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Hanna Swaab
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Andre Aleman
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Rene S. Kahn
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S. van Rijn (&) H. Swaab Department of Clinical Child and Adolescent Studies, Leiden University
, Wassenaarseweg 52, Postbus 9555, 2300 RB Leiden,
The Netherlands
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S. van Rijn R. S. Kahn Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht
,
Utrecht, The Netherlands
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S. van Rijn Department of Experimental Psychology
, Helmholtz Instituut,
Universiteit Utrecht
,
Utrecht, The Netherlands
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A. Aleman BCN NeuroImaging Center, University of Groningen
, Groningen,
The Netherlands
Although Klinefelter syndrome (47,XXY) has been associated with psychosocial difficulties, knowledge of the social behavioral phenotype is limited. We examined specific social abilities and autism traits in Klinefelter syndrome. Scores of 31 XXY men on the Scale for Interpersonal Behavior and the Autism Spectrum Questionnaire were compared to 24 and 20 control men respectively. XXY men reported increased distress during social interactions and less engagement in specific social behaviors. In the XXY group, levels of autism traits were significantly higher across all dimensions of the autism phenotype. These findings call for a clinical investigation of vulnerability to autism in Klinefelter syndrome. Klinefelter syndrome might serve as a model for studying a role of the X chromosome in social behavioral dysfunction and autism-like behavior.
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Klinefelter syndrome affects approximately 1 in 700 men
and is the most commom sex chromosomal disorder. Men
with this syndrome have an extra X chromosome, giving
rise to the XXY chromosomal pattern. This sex
chromosomal aneuploidy results in a variety of phenotypes
including hypogonadism, androgen deficiency and
infertility (Lanfranco et al. 2004). Cognitive and behavioral
dysfunctions in Klinefelter syndrome have generally been
under-appreciated relative to endocrinological and physical
features. However, there is an awareness of behavioral and
cognitive abnormalities (Boone et al. 2001; Geschwind
et al. 2000). Although there is a general impression that
men or boys with Klinefelter syndrome often struggle with
social situations (for example at school or at work),
knowledge of the social behavioral phenotype of
Klinefelter syndrome is limited. Previous studies have
predominantly assessed global functioning (for example
academic achievement, occupation or marital status) rather
specific social abilities. Some studies have specifically
focused on social adjustment in adolescents and men with
Klinefelter syndrome, but these studies have primarily
collected categorical data (for example, someone can be
either sociable, passive or shy) or the studies included
small sample sizes or lacked control data from individuals
from the general population. These studies suggest that
individuals with Klinefelter syndrome are at risk for
psychosocial and emotional problems such as social
withdrawal, social anxiety, shyness, impulsivity and
inappropriate social behavior (Bender et al. 1999; Geschwind
et al. 2000; Geschwind and Dykens 2004; Ratcliffe 1999;
Simm and Zacharin 2006). In early adulthood a significant
portion of the XXY men report having few or no friends,
poor relations with siblings and parents, little energy and
initiative, and few or no sparetime interests (Nielsen et al.
1980).
Although speculative, difficulties in coping with the
social environment may be indicative of an increased
vulnerability for autistic traits in boys and men Klinefelter
syndrome. Tentative support for this hypothesis comes
from recent case studies of individuals with Klinefelter
syndrome diagnosed with an autism spectrum disorder (Jha
et al. 2007; Merhar and Manning-Courtney 2007). Also,
population based studies investigating genetic disorders in
individuals with autism have commented on the
co-occurance of autism and the XXY pattern (Kielinen et al. 2004;
Konstantareas and Homatidis 1999). However, to our
knowledge, there has been no study of autism features in a
large sample individuals with Klinefelter syndrome.
The aim of our study was to investigate specific social
abilities in a large sample of adult men with Klinefelter
syndrome and assess whether Klinefelter syndrome may be
associated with increased levels of autistic traits. In an
attempt to improve our understanding of the social
behavioral phenotype of Klinefelter syndrome, our study
included a quantitative measure of the degree to which
XXY men participate in specific social behaviors and at the
same time the degree to which XXY men are distressed
during these social situations as compared to men from the
general population. Importantly, this measure allows a
quantification of social capacities that are normally
distributed in the general population. Also, it has shown to be
sensitive to the effects of social skills training, indicating
that it is a sensitive measure of individual differences in
social behavior.
To explore (...truncated)