As we covered in our previous posts, the reason why a person develops OCD is a combination of a few factors, one of which is genetics. How do genetics play a role in the development of OCD?
Experts have yet to find the particular gene that causes OCD. However, research indicates that OCD runs in families, which means that genetics is likely to play a role in the development of OCD. The chances among relatives having OCD is 5 times higher than among relatives that do not have OCD (WebMD, Inc., 2000). In a study led by Dr. Gerald Nestadt, involving 1,406 people with OCD, 1,000 close relatives of the patients with OCD and the general public, it was found that patients with OCD had a “significant association” on chromosome 9, which is near a gene called protein tyrosine phosphokinase (PTPRD) (Honor, 2014). This gene has been related learning and memory. This gene also has association to some attention deficit hyperactivity disorder (ADHD) cases. A few symptoms of ADHD are similar to those of OCD.
According to research based in the US, where DNA samples from patients with OCD were examined, results proved the possibility that OCD may be developed because of a rare combination of two mutations within the human serotonin transporter gene (hSERT) (UK, n.d.). This gene codes for the human serotonin transporter and also the transport protein used for the reuptake of serotonin from the synapse between two neurons. As we covered in the earlier posts, serotonin helps to regulate mood naturally.
The first mutation is associated with increased expression of the hSERT gene, therefore having more transport proteins on the membrane of the neuron. This causes an increase in reuptake of serotonin, decreasing the amount of serotonin that is available for communication. The second mutation has similar cellular effects. These two mutations combined causes a significantly lower levels of serotonin available for communication.