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Updated: May 6, 2026

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia
Published on: June 15, 2011
Klinefelter syndrome and risk of psychosis, autism and ADHD
Martin Cederlöf1, Agnes Ohlsson Gotby, Henrik Larsson
1Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, SE-171 77 Stockholm, Sweden.
Background:
Schizophrenia, bipolar disorder, autism spectrum disorders and ADHD might be overrepresented in Klinefelter syndrome, but previous investigations have yielded inconclusive results.
Methods:
We compared a national sample of 860 Klinefelter patients in Sweden with 86 000 matched population controls. To assess the risks of schizophrenia, bipolar disorder, autism spectrum disorder and ADHD in Klinefelter patients, we estimated odds ratios and 95% confidence intervals using conditional logistic regressions.
Results:
Klinefelter patients had almost four times higher risks of schizophrenia, odds ratio (OR) = 3.6, 95% confidence interval (CI) 2.0-6.7 and bipolar disorder (OR = 3.8, CI 1.8-7.6) and about six times higher risk of autism spectrum disorder (OR = 6.2, CI 4.0-9.4) and ADHD (OR = 5.6, CI 4.0-7.8).
Conclusions:
The risk of psychosis, autism and ADHD is increased in Klinefelter patients. These findings indicate an X chromosome-related factor in the etiology of the studied psychiatric disorders, and may also have implications for treatment of patients with Klinefelter syndrome.
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