No Evidence of an Association Between Two Genes, EDN1 and ACE, and Childhood-Onset Mood Disorders

Recent evidence supports a pathological link between heart disease and depressive symptoms, suggesting that depression is both etiologic and prognostic to heart disease. Thus, biological molecules which are at the interface between heart and mind are plausible candidate genes for depressive disorders. To investigate this line of enquiry we have investigated two genes, Endothelin I (EDN1) and Angiotensin-converting enzyme (ACE) in a family-based sample with childhood-onset mood disorders (COMDs). EDN1 is highly expressed in endothelium where it acts as a potent vasoconstrictor, and is also expressed in the brain where it exhibits neurotransmitter characteristics. ACE acts as a potent vasopressor, and interacts with the hypothalamic-pituitary-adrenocortical (HPA) system, which is often dysregulated in mood disorders. Furthermore, ACE has recently been found to be associated with major depression. Polymorphisms were selected to best capture the genetic variation at the two loci, and to replicate previous associations. The markers were genotyped across EDN1 and ACE in a sample comprised of 382 Hungarian nuclear families ascertained through affected probands diagnosed with a mood disorders before the age of 15. We found no evidence of association between either of these genes and COMD. Consequently, we were unable to support our hypothesis that these two genes, which are involved in both vascular and brain functions are contributing to the susceptibility to mood disorders of children/adolescents. (C) 2009 Wiley-Liss, Inc.