engleski

Dopamine Beta-Hydroxylase (DBH) Activity and -1021C/T Polymorphism of DBH Gene in Alzheimer’s disease

Background: Alzheimer’s disease (AD) is complex and polygenic disorder. Polymorphisms within the dopamine beta-hydroxylase (DBH) gene could be related to etiology of Alzheimer’s disease (AD), given the well-documented changes in the catecholamine-mediated neurotransmission that occurs in this disorder. The aim of the present study was to investigate DBH -1021C/T gene polymorphism and plasma DBH activity between patients with AD and healthy controls. Methods: Plasma DBH activity and DBH -1021C/T polymorphism were determined in 155 patients (mean ± SD age 66.3 ± 11.2 years ; MMSE = 13.1 ± 8.1) with AD (NINCDS-ADRDA and DSM-IV-TR criteria) and 188 healthy controls (66.3 ± 11.2 years). The patients were subdivided into two subgroups according to the presence or absence of psychotic features and according to the early (F00.0) or late (F00.1) onset AD. Plasma DBH activity was determined by a photometric method and DBH genotype by standard RFLP technique. Results: Among AD patients 62%, 31% and 6.5% were carrying CC, CT and TT genotype, while 61.5%, 33, 5% and 5.3% of healthy controls were carrying CC, CT and TT genotype, respectively. DBH genotype (Chi-square=0.38 ; df=2 ; p=0.825) and allele (Chi-square=0.038 ; df=1 ; p=0.90) frequencies were similarly distributed between healthy controls and patients with AD, between patients with or without psychotic features (Chi-square=1.90 ; df=2 ; p=0.386) and between patients with early- and late-onset AD (Chi-square=3.07 ; df=2 ; p=0.215). A significantly (p<0.001) lower plasma DBH activity was found in AD patients compared to healthy controls, there was a significant difference in plasma DBH activity (p<0, 0001) between different genotypes but interaction tested between the two independent factors gave no significant difference. Conclusion: The results suggest that genotype-controlled measurement of plasma DBH activity might be used as a potential biological marker in AD.

dopamine beta-hydroxylase; plasma; Alzheimer's disease; enzyme activity

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