The Role of the Dopamine β-hydroxylase Functional Polymorphism in Patients with Early-Onset Parkinson’s Disease in the Turkish Population
Sevda Erer1
, Işıl Ezgi Eryılmaz2, Dilara Kamer Çolak2, Ünal Egeli2, Gülşah Çeçener2, Berrin Tunca2, Ece Karakuş3, Beril Dönmez Çolakoğlu4, Ayşe Bora Tokçaer5, Esen Saka Topçuoğlu6, Duruhan Meltem Demirkıran7, Muhittin Cenk Akbostancı8, Mehmet Zarifoğlu1, Okan Doğu9, Hakan Kaleağası9, Gülay Kenangıl10, Raif Çakmur4, Bülent Elibol6
1Bursa Uludag University Faculty of Medicine, Department of Neurology, Bursa, Turkey
2Bursa Uludag University Faculty of Medicine, Department of Medical Biology, Bursa, Turkey
3Bursa Uludag University Faculty of Medicine, Bursa, Turkey
4Dokuz Eylul University Faculty of Medicine, Department of Neurology, Izmir, Turkey
5Gazi University Faculty of Medicine, Department of Neurology, Ankara, Turkey
6Hacettepe University Faculty of Medicine, Department of Neurology, Ankara, Turkey
7Cukurova University Faculty of Medicine, Department of Neurology, Adana, Turkey
8Ankara University Faculty of Medicine, Department of Neurology, Ankara, Turkey
9Mersin University Faculty of Medicine, Department of Neurology, Mersin, Turkey
10Bahcesehir University Goztepe Medical Park, Department of Neurology, Istanbul, Turkey
Keywords: Early-onset Parkinson’s disease, dopamine β, -hydroxylase (DBH), polymorphism, Turkish population
Abstract
Objective: A functional single nucleotide polymorphism, rs1611115, in the dopamine β-hydroxylase (DBH) gene, is reported to regulate plasma enzyme activity levels. Here, we report the first evaluation of this association in patients with early-onset Parkinson’s disease (EOPD) and healthy controls in the Turkish population.
Materials and Methods: We evaluated the DBH rs1611115 polymorphism in 114 (64 male and 50 female) Turkish patients with EOPD and 58 sex- and agematched healthy controls from the Turkish population. A total of 27.2% (n=31) of our patients who had any variation including pathogenic or non-pathogenic missense, non-sense and/or intronic variation with unknown significance in EOPD genes were grouped as “variation-positive EOPD”. A total of 50.8% (n=58) of our patients were grouped as “variation and family history-negative EOPD” and the possible contribution of the DBH rs1611115 polymorphism to EOPD pathogenesis was evaluated in this group.
Results: There was no significant difference in the genotypic and allelic frequencies of DBH rs1611115 between patients with EOPD and controls. To our knowledge, this is the first evaluation of the DBH rs1611115 polymorphism in patients with EOPD and ethnically matched controls in the Turkish population.
Conclusion: Some previous studies have reported conflicting association results between DBH rs1611115 polymorphism and PD pathogenesis in different ethnic groups. Therefore, further studies are needed to evaluate dopamine metabolism-related genetic variants and to determine their possible roles in EOPD susceptibility in the Turkish population.