Role of genetic and environmental factors in tic disorders

The aim of this thesis was to study associations between genetic and environmental factors and severity of tics and comorbid symptoms in patients with a tic disorder.
First, we investigated perinatal factors and found that patients who had been exposed to prenatal smoking exposure had more severe comorbid symptoms, and patients born after perinatal complications more severe tics and comorbid features.
We also addressed serotonergic and dopaminergic genes, both separately as well in interaction with perinatal factors. Polymorphisms of the solute carrier family 6, member 3 (SLC6A4), monoamine oxidase A (MAOA), dopamine receptor D4 (DRD4) and SLC6A3-genes were associated with severity of tics and comorbid symptoms. Interactions between delivery complications and the MAOA and DRD4 polymorphisms were related to severity of tics and co-occurring internalizing symptoms; and between pregnancy complications and the SLC6A3 gene to severity of obsessive-compulsive symptoms.
In children with a tic disorder and healthy controls, we have also investigated serum concentrations of general immune markers and immunoglobulines. Regarding the general immune markers we could not demonstrate any relations, indicating no substantial role of the immune system in tics, although the immune system may be involved in the expression of tic disorders. Interestingly, we did find lower levels of certain immunoglobulines in children with tics, which may lead to an increased susceptibility to infections.
This thesis has demonstrated associations between tics and perinatal adversities, serotonergic and dopaminergic genes, and immunological factors. Future studies that replicate our results and clarify underlying mechanisms are warranted.

	Titel en inhoud
	Hoofdstuk 1
	Hoofdstuk 2
	Hoofdstuk 3 (Embargo t/m 01-09-2011)
	Hoofdstuk 4 (Embargo t/m 01-09-2011)
	Hoofdstuk 5 (Embargo t/m 01-09-2011)
	Hoofdstuk 6 (Embargo t/m 01-09-2011)
	Hoofdstuk 7 (Embargo t/m 01-09-2011)
	Engelse samenvatting
	Nederlandse samenvatting
	Dankwoord
	Publicaties
	Volledige dissertatie (Embargo t/m 01-09-2011)

Meer informatie in de catalogus
Meer informatie in Picarta