Genetic counselling and screening; is it time we embraced it?

Award-winning actress, Angelina Jolie underwent a preventable double mastectomy in 2013 to lower her chances of developing breast cancer.

This medical choice was informed by genetic tests that revealed that she carried the BRCA1 gene that predisposed her to the disease as well as ovarian cancer.

Having lost her mum, aunt and grandmother to the disease, the celebrity opted to have the surgery to improve her odds of contracting it.

The Oscar winner additionally had her ovaries and fallopian tubes removed to lower her risk of ovarian cancer.

Genetic screening and counselling

Genetic counselling involves informing and advising individuals and couples who may be at an elevated risk of diseases that tend to have a genetic predisposition. It can be traumatic to learn of some hereditary illness in yourself or your children.

The aim is usually to help the concerned parties consciously learn, understand and most importantly adapt to the implications and adjust – psychologically, medically and socially - to a possible genetic condition or congenital abnormality.

Individuals can possibly initiate early treatment or management for better outcomes. With increasing awareness about health issues, especially non-communicable diseases, more people are encouraged to seek genetic screening to improve their odds of living without genetic disease.

This is despite the fact that the presence of certain genetic risks does not automatically equate to the definite development of the disease.

Congenital abnormalities

Congenital abnormalities are responsible for a significant burden of disabilities among children worldwide.

In Kenya, the overall occurrence of congenital malformations is about 6.3 in every 1000 children. This is according to a study, the first of its kind conducted in Kenya and published in the Journal of Tropical Paediatrics in 2013.

There could be a high chance that such cases are underreported due to possible stigmatisation and rejection by family and the community.

When you are trying to have a baby

Your doctor may refer you for genetic counselling when there are concerns about;

Your ability to get pregnant You or your partner carrying a gene even without expressing the condition Genetic conditions such as haemochromatosis, haemophilia and muscular dystrophy that may affect your baby during infancy because they run in your or partner’s family    Genetic conditions in a previous pregnancy History of stillbirth, several miscarriages and infertility

When you are pregnant

Ultrasounds and some blood tests can show abnormal parameters in a growing foetus.

According to Fertility Point Kenya, some genetic diseases resulting from chromosomal defects could prevent a pregnancy from progressing.

Some of the genetic malformations in an unborn baby may be due to:

Infection: one in three pregnant women with cytomegalovirus infection in pregnancy have been shown to pass the infection to their babies, which eventually causes birth defects and other health problems. Exposures such as X-rays, some drugs, chemicals and medicines can make changes in genes resulting in congenital malformations. Pregnant woman who has cystic fibrosis, sickle cell anaemia; or if such conditions run in her family or that of her partner A woman who could be having a child with a relative

Signs of a genetic disorder in a child

Delayed milestones Hearing and vision problems Physically observed birth defects Intellectual disability

Notable disorders

1.Cystic fibrosis (CF)

CF is a hereditary disorder that affects the cells responsible for the production of mucus, sweat and digestive juices.

Since such secretions are normally slippery so that they function optimally as lubricants, a defective gene in CF causes thickening of such secretions which end up clogging ducts and tubes, causing severe damage to the digestive system, lungs and other body organs.      

2.Down syndrome (DS)

Down Syndrome is a chromosomal disorder that results from a child having three copies of chromosome number 21 instead of the usual two (one from each parent).

According to Pathologists Lancet Kenya, despite it being a well-known cautionary statement that women above 35 years are at a higher risk of conceiving babies with DS, 80 per cent of children born with the condition are from mothers below the age of 35.

3.Neural tube defects

These are congenital anomalies that affect the central nervous system. They result from the failure of the neural tube to close at around the third or fourth week of pregnancy.

Types of neural tube defects include:

Spina bifida, which is associated with delayed milestones and paralysis Encephalocele, which can cause seizures, motor and vision impairments Hydrocephalus, which builds up fluid in the brain Anencephaly, where the baby is born without parts of the brain or skull. This condition is fatal.

The cause of neural tube defects is believed to be a combination of genetic, nutritional and environmental factors.

Research indicates that Vitamin B and folic acid intake before conception reduces the risk of neural tube defects by up to 70 per cent.

The Ministry of Health in Kenya mandated the fortification of maize and wheat flour and there are additional recommendations for pregnant women to consume 400 microgrammes of folic acid daily to reduce the risk of neural tube defects.

 

- Nancy Nzalambi is a public health research scientist