What is (G6PD) Glucose-6-Phosphate Dehydrogenase Deficiency

Title：Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD Deficiency)

Heading: Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD Deficiency)

Sub-heading: What is G6PD Deficiency

Nurse: Hello everybody,have you ever heard of an inherited condition called Glucose-6-Phosphate Dehydrogenase Deficiency? It is also known as G6PD Deficiency in short or Favism. When taking certain drugs or foods such as fava beans or in contact with mothballs. People with G6PD Deficiency will develop acute haemolysis that is sudden damage of the red blood cells. In view of this the Department of Health provides a newborn screening programme for G6PD Deficiency. In order to find it out early and prevent health problems caused by damaged of the red blood cells. The Genetic Screening Unit of the Clinical Genetic Service under the Department of Health performs screening tests for babies born in hospitals under the Hospital Authority by testing the umbilical cord blood. For those babies born in private hospitals parents can consult their private hospitals, obstetricians or paediatricians for further information. Let us learn more about this condition by watching how a nurse counsels a couple with a G6PD Deficient baby.

Scene: Mrs Au's baby confirmed to have Glucose-6-Phosphate Dehydrogenase Deficiency. Nurse Tong from Genetic Screening Unit of Clinical Genetic Screening Service of the Department of Health counsel Mrs. Au through the phone.

Nurse Tong: Hello! This is Nurse Tong calling from the Genetic Screening Unit of the Department of Health. May I speak to Mrs. Au please?

Mrs. Au: Speaking, what's up?

Nurse Tong: Mrs. Au, congratulations on your new baby. Do you remember the Hospital has taken some umbilical cord blood from your baby for testing? Now we've got the result. Your baby is confirmed to have Glucose-6-Phosphate Dehydrogenase Deficiency, a condition commonly called G6PD Deficiency or Favism.

Mrs. Au: Oh, never. what's the problem with my baby? Is it serious?

Nurse Tong: Oh please don't get too worried.

Mrs. Au: Nurse Tong, could you explain a bit more about it?

Nurse Tong: Sure, G6PD Deficiency is the most common inherited metabolic disease in Hong Kong. It is also very common in Southern China. People with this disease do not have enough amount of an enzyme called G6PD in their red blood cells. This enzyme helps to keep red blood cells stable. Most affected people do not have any symptoms. When they are exposed to some Chinese or Western medicine, mothballs or have serious infection. Their red blood cells may be damaged in a large scale within a very short time. If this happens, large amount of haemoglobin will be broken down into excessive bilirubin (a pigment). This in turns overloads the liver and results in severe jaundice ( i.e. yellowing of the skin and the eyes).

Mrs. Au: It sounds serious. What can I do for my baby?

Nurse Tong: Try not to be too frightened. In fact, such a rapid breakdown of red blood cells can be prevented. People with G6PD Deficiency usually enjoy good health if they avoid exposing to certain triggers.

Mrs. Au: So, Nurse Tong, what should I do?

Nurse Tong: Starting from today you have to observe for any jaundice that is yellowing of skin of your baby. New born babies usually develops some degree of jaundice on 3 to 5 days after birth. This will gradually go away without affecting the health of the baby. On the other hand, if a baby with G6PD Deficiency is exposed to certain triggers that caused the breakdown of the red blood cells. The jaundice may appear on the first day after birth or at a later time. Moreover the jaundice may persist or even get worse.

Mrs. Au: What will happen to babies if jaundice persist and get worse?

Nurse Tong: Just as I've mentioned breaking down of the red blood cells produce a lot of bilirubin. This pigment can enter the brain of the new born baby causing long term brain damage like hearing loss, limp movement disorder and intellectual impairment etc. However with early detection and treatment the jaundice can be controlled effectively. So please do arrange an appointment with the Maternal and Child Health Centre as soon as possible to follow up your baby's jaundice.

Mrs. Au: So apart from jaundice, are there other symptoms I have to take note of?

Nurse Tong: The major symptoms include: yellowing of the white of the eyes and dark coloured urine. Besides, the baby may appear overly tired and sleepy. Older children may look pale and extremely tired. They may also complain of difficulty in breathing and heart beating rapidly. If the above symptoms are observed, you should consult the doctor immediately.

Mrs. Au: Just now you've mentioned that our baby should avoid exposing to certain triggers, so what are these triggers?

Nurse Tong: It's a very good question. People with G6PD Deficiency should remember to avoid the following things for their whole life: Firstly avoid the following Chinese herbal medicines such as Rhizoma Coptidis(Huang Lien) , Calculus Bovis (Neu Huang), Flos Chimonanthi Praecocis (Leh Mei Hua), Flos Lonicerae (Kam Ngan Fa) and Margaritas. Secondly Western medicine such as certain antibiotics, Antimalarials, Aspirin group Antipyretics. If used in high dose should be avoided as well. To make it simple all medicines should be prescribed by doctors. In order to avoid taking those drugs which can trigger red blood cell damage. Thirdly for food stuff, don't let your baby eat fava beans that is broad beans or their products such as fava pastry. Lastly for household products, avoid your baby in contact with mothballs or naphthalene-containing products. The above information is listed on the G6PD Deficiency card also known as green card and the leaflet on G6PD Deficiency produced by The Department of Health. Please keep this handy green card with you all the time

Mrs. Au: Nurse Tong, we haven't got the green card yet. How can I get it?

Nurse Tong: Don't worry. If you haven't received it from your hospital, we will post it to you in a few days. Finally remember to show this green card to your doctor and inform him your baby has G6PD Deficiency. Do you have any other questions?

Mrs. Au: Hmm, not now, thanks.

Nurse Tong: Should you have any other questions, you can call our hotline
2361 9979 or, ask the nursing staff or medical staff in the Maternal and Child Health Centres.

Scene: Mr Au and Mrs Au remove all triggers causing damage of red blood cells from their home.

Mr. Au: Mummy, I've followed nurse Tong's advice and removed all the food and products our baby should avoid. Like that Flos Lonicerae and Margaritas we've bought before. The mothballs inside our wardrobes have also been removed. I've also reminded grandma, grandpa and the maid not to use mothballs anymore. Oh, how about that Bo Ying Tan and insecticide? Should we dispose of them as
well?

Mrs. Au: Hmm, let's ask the nurse in the Maternal and Child Health Centre next time

Sub-Heading: Frequently Asked Questions

Scene: Mr Au and Mrs. Au bring their baby to Maternal and Child Health Centre for registration.

Nurse HO: Good morning Mr. and Mrs. Au. I'm Nurse Ho. I've just checked your baby's jaundice. It's not very high, so you don't need to worry. Today, it's your first visit to our centre. Do you have any questions about taking care of your baby?

Mrs. Au: Nurse Ho my baby has G6PD Deficiency,can I continue breastfeeding him?

Nurse HO: In general, you can continue breastfeeding your baby. However, if you need to take those medicines or Chinese herbal medicines stated on the green card. You have to stop breastfeeding temporarily to prevent passing those medicine to the baby via the milk. Meanwhile it's better that you continue to express breastmilk to maintain milk supply. In that case you can continue breastfeeding after stopping those medicines.

Mrs. Au: Nurse Tong of the Genetics Screening Unit told me that people with G6PD Deficiency should avoid certain Chinese herbal medicines and Western drugs. Can my baby take those Chinese folk medicine like Bo Ying Tan and traditional milk supplement for babies indigestion?

Nurse HO: Indeed, parents should not give medicine to their babies without any doctor's prescriptions. As the Bo Ying Tan contains Calculus Bovis and Margaritas, we should not give this to babies with G6PD Deficiency. The ingredient of over the counter herbal supplement for babies indigestion varies greatly. It's better to avoid giving this to babies. If there really is a need, you should seek advice from a qualified Chinese medicine practitioner.

Mrs. Au: Besides the food mentioned in the green card, is there any other food that my baby should avoid?

Nurse HO: Whenever you buy anything, you should check ingredients for any triggers stated on the green card. For example certain brands of vermicelli and mixed beans may contain fava beans. If you are not sure check with the manufacturer or doctor directly.

Mr. Au: We have to avoid using mothballs, but how about camphor?

Nurse HO: According to the latest research findings, natural camphor will not trigger breakdown of red blood cells in people with G6PD Deficiency. However the purity of camphor containing products in the market varies. Therefore it is better not to use them.

Mr. Au: Can we also use scented aroma, fabric softener and insecticide?

Nurse HO: Except those triggers mentioned in the green card, there is no current evidence showing that aroma, fabric softener, food or products containing menthol, chamomile tissue and diapers, insect repellents, mosquito coil and medicated oil etc can damage the red blood cells in people with G6PD Deficiency. However you should check the ingredients before using them. Should you have any doubts, you'd better consult the manufacturer or your doctor.

Mr. Au: If a baby with G6PD Deficiency, does not have any problems after eating the food which should be avoided. Can he eat that food in the future?

Nurse HO: Even though a baby with G6PD Deficiency has no adverse effect after taking those food that may trigger haemolysis. You shouldn't let your baby eat them again. The degree of damage to the red blood cells depends on other factors like the person's health condition and the amount of triggers exposed to. Therefore for safety's sake, the baby should avoid taking those foods for their entire life.

Mr. Au: When he goes to school, is there any problem if his classmate's uniform has a mothball odour?

Nurse HO: It's common that the uniform of classmates carries odour of mothballs. However the dose of mothballs is much lower and it would not lead to haemolysis. If your child smells the odour of mothball, he'd better get away from it. More important is the affected person and their caregiver should not use mothballs for their clothes. Do you have any other questions?

Mr. Au: No, that's very clear already. Thank you for your explanation.

Nurse HO: Please remember to come to our workshop on G6PD Deficiency next month.

Sub-heading: Inheritance of G6PD Deficiency

Scene: A group of parents attending the G6PD workshop in Maternal and Child Health Centre

Nurse Ho: Good morning parents. I am Nurse Ho. Welcome to today's workshop on Glucose-6-Phosphate Dehydrogenase Deficiency, a condition commonly called G6PD Deficiency or Favism. Today I'll focus on the inheritance pattern of the condition and answer some of your questions. Do you know that G6PD Deficiency is the most common metabolic disease in Hong Kong? Around 4.5% of baby boys and 0.5% of baby girls in Hong Kong have G6PD Deficiency.

Dad A: Nurse Ho, my wife and I do not have G6PD Deficiency. why does our son have it?

Nurse Ho: G6PD Deficiency is an X-linked recessively inherited condition. X-linked means that gene responsible for this condition is on the X chromosome one of the sex chromosomes. Being recessively inherited it means that not all generations will have this disease. Boys only have one X chromosome. When this carries the gene, he will get G6PD Deficiency. On the other hand, girls have two X chromosomes. Therefore, if only one of her X chromosome carries the G6PD Deficiency gene and the other X chromosome is normal. She will only be a carrier of the gene, but with no disease. If both of her X chromosome carry this gene, she will get G6PD Deficiency. That is why most of the people with G6PD Deficiency are males. In your situation you do not have the G6PD Deficiency. But your wife is likely a carrier of the gene.

Dad A: So, if we have a baby in the future, will that baby inherit G6PD Deficiency?

Nurse Ho: If mother is the carrier of G6PD Deficiency and father is unaffected. For each pregnancy, there is a 50% chance that a son will have G6PD Deficiency and 50% chance being unaffected. If the baby is a daughter then there will be 50% chance that she will be a carrier of the deficient gene and the rest will not be affected.

Mum A: My son has G6PD Deficiency. If he gets married in the future, will his children inherit the
same condition?

Nurse Ho: For people with G6PD Deficiency their children may or may not inherit the condition. It depends on the genes of their partners. If the father is G6PD Deficient and mother is unaffected. Then for each pregnancy all sons will not be affected. While all daughters will be carriers of the deficient gene. If the father is G6PD Deficient and mother is a carrier of the gene. Then for each pregnancy there is a 50% chance for a son to be G6PD Deficient and 50% chance he will be unaffected. On the other hand there is a 50% chance for a daughter to be G6PD Deficient and the rest will be a carrier.

Mum B: What about my daughter? She has G6PD Deficiency. Will her baby have the condition?

Nurse Ho: If the mother is G6PD Deficient and father is unaffected. Then for every pregnancy all sons will be G6PD Deficient. All daughters will be carrier. In addition, pregnant ladies should inform their doctor about her family history of G6PD Deficiency for antenatal counseling. Although there are no preventive measures for the condition during pregnancy. Early detection and with the right precaution can protect babies from any harm caused by acute haemolysis.

Dad B: In this case, does my baby need regular blood testing and follow up consultation?

Nurse Ho: Provided that people with G6PD Deficiency can ensure lifelong avoidence of the food stuffs and products mentioned in G6PD green card, it is not necessary to have regular blood taking or follow up consultation.

Dad A: I have one more question. If my child grows up and his immunity becomes stronger. Can he recover from this disease?

Nurse Ho: G6PD Deficiency is an inherited disease, it is not the problem of the immune system. Therefore the baby will not outgrow this with age or when his immunity is stronger. If babies with G6PD Deficiency can avoid exposure to triggers. They can lead a healthy and active life as other children. Therefore, please always take with you the green card and inform medical staff about the G6PD Deficient status of your baby during consultation. Also, let your child know that he has the condition and teach him to take precautions to the food or products mentioned on the green card. Do you have any other questions?

All parents: No, thank you very much.

Scene: Mr. Au and Mrs. Au return home after the workshop

Mr. Au: Mummy please don't put the green card on the sofa. Have you forgotten what the nurse has said? We should always bring the green card with us. In addition we have to bring along this card during every consultation.

Mrs. Au: Oh, sorry. Could you put the green card in my hand bag please?

Mr. Au: Okay

Nurse: After watching this scenario, you should understand more about G6PD Deficiency. Let's go over the main points

1. Children should avoid exposing to triggers of haemolysis that is damage to red blood cells.
2. Should there be any signs and symptoms of acute haemolysis, please consult doctor immediately.
3. Always bring along with you the G6PD Deficiency card.
4. Inform medical staff that your baby has G6PD Deficiency during consulatation
5. Let the child understand G6PD Deficiency at the earliest possible age.
6. Teach him to avoid food and products which can trigger haemolysis.

Although G6PD Deficiency will not be recovered when the child grows up. If the affected person can pay attention to the above precautions, he can also enjoy good health like other children. Finally, if you wish to learn more information about G6PD Deficiency or to receive telephone counseling, you can dial the following hotline 2361 9979 or visit the following websites www.cgs.dh.gov.hk or www.fhs.gov.hk

Credits:
http://www.fhs.gov.hk/english/mulit_med/000018.html