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Role of the Y chromosome in sex differences in ADHD and schizophrenia

Stergiakouli, Evangelia 2010. Role of the Y chromosome in sex differences in ADHD and schizophrenia. PhD Thesis, Cardiff University.

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ADHD and schizophrenia are neurodevelopmental disorders that are more prevalent in males and show sex differences in age of onset or severity. The Y chromosome is potentially an important influence on male susceptibility to neuropsychiatric disorders. The way the Y chromosome could increase risk to neuropsychiatric disorders is directly or indirectly by interacting with autosomal genes expressed in the brain. In addition, it could modify the disease phenotype. However, due to difficulties arising from the lack of recombination and widely accepted nomenclature, the Y chromosome has been largely excluded from genetic and genomic studies of neuropsychiatric disorders. To overcome this lack of knowledge, 9 Y chromosome markers were selected to represent the main Y chromosome haplogroups that are present in the U.K. and they were genotyped in a sample of 210 cases with ADHD, 313 cases with schizophrenia and 637 U.K. controls. Statistical analysis of Y chromosome haplogroups revealed that although there was no significantly increased representation of any haplogroup in cases with ADHD or schizophrenia compared to controls, there was evidence of a possible modifying effect on the phenotype of ADHD and schizophrenia. Y chromosome haplogroup 3 was associated with higher performance and full scale IQ within the sample of patients with ADHD. Haplogroup 1 was associated with better outcome and higher educational level within the sample of patients with schizophrenia. There was no association of Y chromosome haplogroups with IQ in a population sample of 3,749 individuals. Y chromosome haplogroups were also tested for interaction with tyrosine hydroxylase SNPs because animal studies suggest this is biologically plausible. Although there was no evidence of interaction, three tyrosine hydroxylase SNPs showed nominally significant association in the sample of male patients with schizophrenia. This study is one of the largest Y chromosome studies in the UK. It suggests that although Y chromosome variation does not appear to be associated with ADHD or schizophrenia, it may modify cognitive performance and clinical features.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Medicine
Subjects: Q Science > QH Natural history > QH426 Genetics
R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
ISBN: 9781303195730
Date of First Compliant Deposit: 30 March 2016
Last Modified: 19 Mar 2016 23:29

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