Host:

Dopamine, serotonin, adrenaline, these common chemicals are all neurotransmitters in the brain. Neurotransmitters are nerve substances, a bridge for disseminating information, they let us have normal feelings and movements. But some children have genetic abnormalities and suffer from a rare disease called neurotransmitter disease. Because the brain lacks certain neurotransmitters, different symptoms may occur.

Today we've invited Dr. Sheila Wong, Associate Consultant of Department of Paediatrics and Adolescent Medicine from Hong Kong Children's Hospital. Hello, Dr Wong.

Dr Sheila Wong:

Hello, Janet.

Host:

Can you share this with us? What are neurotransmitters?

Dr Sheila Wong:

Neurotransmitters, in simple terms, are channel chemicals for nerve cells to communicate with each other. Through these neurotransmitters, the body can run smoothly and we operate well. These include our actions, they can be performed very smoothly. Our emotions, even heart rate and blood pressure regulation can all be performed to the fullest. For example, we have dopamine. Dopamine can help us send movement signals from within the brain to the muscles to perform the actions that we want to do. Serotonin plays an important role in emotions regulation. Adrenaline, as we know, affects heart rate and blood pressure. It's a very important neural communicating substance.

Host:

Doctor, you mentioned many different neurotransmitters. Regarding rare diseases, which one is the most common?

Dr Sheila Wong:

For rare diseases, these neurotransmitters, we classify them as "neurotransmitter diseases". Among children, these diseases are not common. But within these uncommon ones, they are relatively more common ones.

The more common one in clinical practice is dopamine deficiency. There is something wrong with your metabolism. This leads to different diseases. As said before, dopamine is what makes the body move, so, the symptoms are that children will have developmental delays. You can't control your head at the right age, even muscle and limb mobility will decrease. There's less spontaneous movement. Some have low and abnormal muscle tone. Some children have difficulty controlling their eye movements. It can last for several hours. For example, both of their eyes look up, looking in one direction on and off for several hours. This is one of the dopamine deficiency's common clinical symptoms.

Host:

Some symptoms are similar to developmental delays in children. How do you diagnose clinically?

How to diagnose?

Dr Sheila Wong:

In addition to what has just been said, together with some other clinical symptoms, our path to diagnosis includes doctors examining them according to the symptoms, looking at muscle tone, and clinical development assessment combinedd with laboratory examination. It is a cross-disciplinary and cross-team effort. For example, the Hong Kong Children's Hospital has laboratories. One of them helps in performing neurotransmitter testing. We call it cerebrospinal fluid examination. Analyzing the levels of brain neurotransmitters and metabolites would give us a clue. Together with genetic testing, children can be diagnosed with a neurotransmitter disorder. We would then prepare a treatment plan.

Host:

Do we have to wait until the child becomes ill before we can discover this disease? Can the much talked about newborn screening in recent years discover?

Dr Sheila Wong:

Of course, if there are symptoms, you should find out the cause as soon as possible. But we hope that it can be discovered before one gets sick. This is also the spirit of newborn screening programme. We hope that before one gets sick, those cases that can be cured, can be discovered. In the newborn screening programme, there are some diseases called brain neurotransmitters diseases. For example, for a disease named PTPS deficiency, through newborn screening, before the baby gets sick within the first few days after birth, they can already be screened. Then we can give them supplements promptly. Once these children are cured, they can all be very happy, and go to school with other children of the same age, which greatly improves their quality of life and development.

Host:

Doctor, can you tell me more about treatment options?

Dr Sheila Wong:

For example, for PTPS deficiency mentioned earlier, we can directly add dopamine precursor and some auxiliary drugs to improve the condition. These are one of the treatment options.

Host:

Doctor, do you also have cases to share?

Dr Sheila Wong:

Those that are very interesting or inspiring. We saw that before the era of newborn screening programme, we really did see symptoms we mentioned before: developmental delay, very low muscle tone. Some children may for example, in the outpatient clinic, during the more than one and half hour we meet the parents, you see that the child seems to be frozen in terms of movement. Like paused in front of the camera. Because that hour, the child may not have any movement. Sometimes when he is sick, he can cry all night, has trouble sleeping, and there's no apparent reason. Sometimes the parents say, the child will suddenly have abnormal muscle tone, the child with his whole body extended, eyes rolled up on and off for few hours. These can occur every few days.

With these symptoms at the time, they came to our clinic. Then we would treat them. Later we discovered the disease and that after giving some medicines, in some cases, they already reached puberty, for so many years, they couldn't walk well or sit well. But it's really magical that, after medication, we see them walking and running, back to a normal school. These are very encouraging. Also, under newborn screening, even before they get sick, we have already given supplements during the infancy period. They would not have the symptoms. With the screening, we don't see them symptomatic. We are all very happy.

Of course, in neurotransmitters or uncommon diseases, doctors often remember some cases that are encouraging. But we have another group of patients, there isn't necessarily a definite or targeted treatment at the moment. However, for example, at the Children's Hospital, our entire team including Rehabilitation Centre and different specialties, we all work together to optimize their condition. In addition, in the field of medicine in the past 10 to 20 years, it continues to develop. I can feel it myself especially in the field of uncommon diseases. So I want to tell parents, if your child suffers from an uncommon disease, hope is always around. Let's not give up. There is always light.

Host:

Doctor, thank you very much for sharing with us today. Let's wrap it up here.

Goodbye.