How can normal parents give birth to children with genetic diseases?

Genetics - Photo 1.

Doctor Bui Thi Phuong Hoa examines a patient - Photo: BVCC

Parents who give birth to children with genetic diseases do not understand why this happens when they themselves are normal?

Surprised when child has genetic disease

Her child was born healthy and normal, but when her child was 4 years old, Ms. N. ( Nam Dinh ) discovered that her child had muscle weakness. Ms. N. shared that at first, her child did not show any unusual signs, but recently, her child often fell, climbed stairs... and the muscle weakness became more and more obvious. She took her child to the National Children's Hospital, where doctors diagnosed her child with Duchenne muscular dystrophy, a genetic disease.

After being examined at the hospital, the doctors advised her to also examine her youngest son, who was only 2 years old. After examination and testing, the doctors discovered that Ms. H.'s second child also had the same disease as her brother.

With this disease of the child, the doctors could not intervene any further and the disease gradually progressed. The two children grew up but lost the ability to walk by the age of 12 or 13. The child had to use a wheelchair and died early at the age of 20-25.

Ms. L. in Hanoi has lost her children twice for unknown reasons. In 2016, her first baby boy was born healthy. However, not long after, his health deteriorated and he passed away.

During Ms. L.'s second pregnancy in 2018, the whole family rekindled hope, but fate once again tested the couple. Just one month after giving birth to their second son, he contracted prolonged pneumonia, and treatment did not improve. A year later, their second child also left the couple.

Having lost two children, L. and her husband faced a great shock. After five years of recovering, L. and her husband wanted to find the cause in order to prepare carefully for the next birth.

At the Hanoi Andrology and Infertility Hospital, after detailed examination of the medical history of Ms. L. and her family, and careful analysis of the medical history of the two deceased children, the doctor determined that the main cause could be a gene mutation. After performing gene sequencing and consulting with experts, the doctor finally found out that Ms. L. carried a disease-causing mutation on the CYBB gene - an X-linked recessive genetic disorder that causes chronic granulomatosis.

The disease manifests as recurrent pneumonia from the neonatal period, with poor response to treatment. The mother is a healthy carrier of the gene and does not show any symptoms of the disease, but the son, who carries the genetic mutation inherited from his mother, will contract the disease and die. Both husband and wife were surprised because they did not think that the two deaths were due to the mother's genetic disease.

Many families have fallen into despair because their children were born with genetic diseases. Health statistics show that each year in Vietnam, about 40,000 children with congenital disabilities are born, notably, up to 80% of children with genetic disorders are born to healthy parents or have no family history.

Screenable disease

According to Dr. Dinh Thuy Linh (Deputy Director of Hanoi Obstetrics and Gynecology Hospital), genetic diseases today often cause dangerous symptoms in children and most of them cannot be cured. However, genetic screening in couples has not received due attention. Therefore, many couples do not know that they are healthy carriers of the disease gene until they give birth and discover that the child has a genetic disease.

"Many people who come to the hospital wonder why both husband and wife are healthy and normal but their child has a genetic disease. In fact, the condition of healthy people carrying disease genes is very common, but not many people are aware of this. This is the reason why many children are born with congenital genetic diseases," said Dr. Linh.

Dr. Linh explained that when two healthy people carrying the disease gene get married and have a baby, if the baby receives both disease genes from both parents, the child will have a genetic disease (accounting for 25%). Even with some diseases, only the mother carrying the disease gene can pass it on to the child. Currently, there are hundreds of recorded genetic diseases.

According to Dr. Bui Thi Phuong Hoa (head of scientific research and training department, genetic doctor at Hanoi Andrology and Infertility Hospital), single-gene diseases are genetic disorders caused by mutations in one gene.

Based on the genetic mechanism, the disease is divided into two main groups: Dominant single gene mutation group - the father or mother has a disease-causing mutation and passes on the mutated gene, causing the child to also have the disease. Recessive single gene mutation group - both parents are healthy carriers of the mutated gene, if the child receives both mutated genes from the parents, he or she will have the disease, and even be at risk of death.

Scientists have so far identified about 6,000 single-gene diseases. More worryingly, these diseases are hereditary and can continue to affect future generations if not detected and treated promptly.

"Families where both husband and wife carry recessive genes related to single-gene genetic diseases should receive genetic counseling before planning to get pregnant and have children. This not only helps parents understand the risk of having a child with the disease but also supports them in choosing appropriate reproductive support methods. In particular, genetic testing before embryo transfer is recommended to ensure a healthy baby and avoid risks during natural pregnancy," Dr. Hoa recommended.

Who should be screened for genetic diseases?

According to Dr. Linh, a healthy mother and a healthy father will produce a healthy child. There are many genetic diseases that exist in a recessive gene state, so without screening, couples will not know they carry the disease gene because most healthy people carrying the disease gene have completely normal symptoms.

To minimize the risk, screening for carriers of the disease gene is extremely necessary, especially for couples about to get married, couples preparing to have children and pregnant women in the first three months. This not only helps in early detection but also supports the development of effective preventive solutions, protecting the health of future generations.