Ideas & Debate

Genetic tests key to averting disease risk in children

baby

Genetic testing is ideally done before you start trying to get pregnant. PHOTO | FOTOSEARCH

It is the wish of all parents to give birth to healthy children that can go through life ‘stress free’, without having to deal with challenges of debilitating ailments.

Whereas a majority realise this dream, there are some who fail to do so. They end up with babies suffering from various severe genetic conditions.

This is the fate that befell John Onyango and his wife Emily who lost their four-year old baby girl from a genetic condition known as sickle cell disease.

Children with the ailment have sickled-shaped red blood cells that are unable to carry adequate oxygen throughout the body. The disease is characterised by fatigue, weakness, enlarged spleen, chronic anaemia, low immunity, severe joint aches and sporadic painful episodes that can leave patients immobile for days.

There is no cure for the disease. Patients usually rely on certain treatments to manage painful symptoms and boost their immunity. But without access to quality care, kids affected end up losing their lives early in life.

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Despite being careers of the sickle cell gene, the Onyango’s said that they were not aware until their baby was diagnosed with the disease.

“There is nothing as painful to a parent as bringing a child to this world, then watching them suffer and eventually die from a disease that came from you. I feel like I let my baby girl down,” said Ms Onyango as her eyes glistened with tears.

Parents with similar experiences sometimes go through this overwhelming guilt “trip” which can lead to depression and even loss of life without timely intervention.

Many spend sleepless nights wondering if life would have taken a different course for the affected child had they (as parents) been aware that they harboured genes for certain fatal genetic conditions before deciding to have children.

To stop such regrets later in life, couples can undergo a special test known as preconception genetic screening before they begin trying for a baby.

Dr Ahmed Kalebi, Pathologist and Chief Executive Officer (CEO) of Lancet Laboratories in East Africa, says that the procedure, which typically involves testing of blood or saliva samples from interested parties, can enable couples to predict their chances of having children with a genetic disorder.

He notes that the test is important since cariers of hereditary conditions do not usually suffer from symptoms of ailments they carry.

“So you may not know that you have genes for a particular disease unless you are tested.”

Aside from sickle cell disease which is the most prevalent in Kenya, other serious genetic conditions include hemophilia, cystic fibrosis, muscular dystrophy and fragile X syndrome.

According to Dr Kalebi, genes usually occur in pairs (more like twins) and both are supposed to be good.

But among carriers of hereditary conditions, one twin gene is good while the other is bad.

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And thanks to the superiority of the good gene, these people end up leading normal lives without suffering from the symptoms of the genetic conditions they carry.

The problem, he says, usually arises when a carrier marries another carrier. This is because some of their children may end up inheriting the two bad genes (one from each parent) and thus proceed to suffer from full-blown effects of a particular genetic condition.

In the case of sickle cell, carriers possess two copies of the haemoglobin gene - a good one known as ‘A’ and a bad one known as ‘S’. Children who inherit the two bad genes (SS) go ahead to develop sickle cell disease that none of their parents suffered from, but just carried.

Dr Sikolia Wanyonyi, consultant gynaecology and foetal medicine expert at Aga Khan University Hospital (AKUH) says that in spite of its benefits, the demand for preconception screening is still low as most Kenyans lack awareness about it.

“Here, people tend to work backwards. You become pregnant then go to see a doctor. Rarely do people show up to talk about possible risks or go through check-ups and screening tests before making the decision to have a baby.”

“The few that do so are the ones that have had complications with previous pregnancies or those going through fertility problems. And these are not many.” Dr Wanyonyi states that many parents only rush to hospital after birth upon noticing that something is amiss with their child.

“By then, it’s too late and nothing can be done to prevent the occurrence of the genetic disease.”

According to Dr Kalebi, the demand for pre-conception screening is mostly high among foreigners or expatriates as they have been exposed to it abroad.

As such, he states that Kenya is missing out “big time” on global best practices in modern medicine.

“In fact, I can say that our forefathers did better than us when it came to preconception screening. They sought detailed history about death or illness in a particular family before allowing marriage unions between certain people. This prevented the transmission of genetic diseases.”

couple

Couples can undergo a special test known as preconception genetic screening before they begin trying for a baby to stop regrets. PHOTO | FOTOSEARCH

According to Dr David Thuo, consultant gynaecologist at Karen Hospital, preconception screening enables parents to either avert or prepare well for unintended pregnancy outcomes.

He notes that after determining their children’s predisposition to certain genetic conditions, some couples refrain from having babies and choose instead to embrace adoption.

If the test is done before marriage, Dr Thuo says that couples may make a decision to go their separate ways so as to “save” their future children.

In Western countries, where abortion is legalised under medical grounds covering genetic disorders, some parents choose to conceive and thereafter terminate pregnancies for unborn children that test positive for genetic ailments while still in the uterus.

Only healthy ones are carried to term. Among Kenyans that can afford it, the in-vitro fertilisation (IVF) technique can enable them to have their own biological kids that are free from any genetic ailments.

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“This technology gives them the power to choose the destiny that they want for their children,” said Dr Wanjiru Ndegwa, a consultant fertility specialist and gynaecologist at the Footsteps to Fertility Centre.

As part of the IVF process, she notes that the male sperms and female are first fused in the lab, outside the body.

The embryo ensuing from the union is then screened for genetic conditions that the parents carry like sickle cell disease or haemophilia.

A sick embryo is destroyed while a healthy one -free of genetic disorders - is implanted into the mother’s uterus. She will carry it to term and deliver a healthy baby.

“After the procedure, couples get a piece of mind knowing that the unborn child will be okay. He or she will not therefore suffer needlessly from a hereditary condition that they had the power to prevent.”

As an advancement to the IVF approach, scientists are now working on a promising technology known as Gene Editing that makes it possible to repair or edit out defective genes in sick embryos before they are implanted into the uterus (currently, the only option is to discard affected embryos and retain only healthy ones).