Impulse control behaviour (ICB) is defined as failure to resist the temptation or behaviour that may be harmful to self or others. The behaviour disorders are referring to gambling addiction, hypersexuality, obsessive shopping and self-abusive behaviours. Some Parkinson’s patients develop more than one ICB, such as compulsive medication use, pounding or hobbyism. On the other hand, Parkinson’s disorder (PD) is known as chronic movement disorder due to degeneration of the central nervous system. This progressive disorder affects and cause loss of nerve cell, dopamine-secreting neuron, located in substantia nigra in the brain. As PD progresses, the amount of neurotransmitter dopamine that coordinates movement decreases, leaving a person unable to control movement normally. Beside coordinate movement, the dopamine-secreting neuron in dopaminergic system is also involved in reward mechanism, impulsiveness and decision-making processes. Based on previous studies, dopamine receptor (DRD) and N-methyl-D-aspartate 2B (GRIN2B) genes were involved in dopaminergic system.
Mr. Shahidee Zainal Abidin, a PhD candidate under the supervision of GRMRC’s Dr. Michael KH Ling and Dr. Cheah Pike See, in collaboration with Universiti Kebangsaan Malaysia Medical Centre and Universiti Malaya Medical Centre, performed a screening on DRD1-5 and GRIN2B gene to determine if subtle differences in DNA sequences (or known as polymorphisms) could be associated with Malaysian ICB-PD patients. This study, published in BMC Neurology, was done by performing single nucleotide polymorphism (SNP) screening on selected polymorphisms within the DRD1–5 and GRIN2B genes that were previously implicated in predisposing PD patients to the risk of developing ICB. Based on our finding, DRD1, DRD2 and GRIN2B genes were found to be associated with an increase of developing ICB among PD patients. Therefore, a single alteration in DNA sequence might cause the development of ICB among PD patients. However, more investigations are required to improve our understanding of how these polymorphisms can lead to development of ICB in Parkinson’s patients.
For more details:
Authored by : Shahidee Zainal Abidin & Omar Habib