DOWN SYNDROME- LET'S HAVE A TALK

It’s no news to me, perhaps because I’m medically-inclined and seek to know more about interesting issues like this. Nevertheless, I was moved to compassion the first time I saw a child with this condition. Yeah! I felt for both the mother and the child. I was curious about their daily struggles, considering the kind of society that we have. I’m not proud of my actions, but I won’t say I was exactly open and welcoming, despite my compassion.

I tried as much as possible not to let the child have any contact with me. If I, with all my knowledge and exposure, could behave like that, how much more people who know nothing about it? Some of us even have an offensive word to characterise them. We call them MONGOLOIDS! Growing up, I learned through my Social-studies classes that Mongoloids referred to Asians and people with such physical traits, the same way NEGROID was used for blacks. It wasn’t an offensive word then, but I think times have changed. Now, that same word is OFFENSIVE, regardless of whoever you use it for. And I’m sad to think that children born with this condition are referred to in such a derogatory manner, although it’s been officially discontinued by the World Health Organisation since 1965.

While in this bus on the busy street of Lagos studying this innocently-playing child, I had a flashback to my Integrated Science days. My teacher did mention CHROMOSOMAL DEFECTS in children, and as we were known to do, I crammed them all. Of all of them, Down syndrome and Klinefelter syndrome became my household names. I guess it was partly because my teacher loved to set questions on them, asking us to differentiate between them. Aside from that, these words also came in handy anytime I wanted to ‘blow grammar’ and let people believe I have the world of science in my hands. Alas! Here I was, the joke of those years staring at me in the face, confirming that those defects were not stories to make our Biology textbooks full and interesting. They were stuff that happened and are still occurring. 

What piqued my interest in this same subject again? I will say it’s compassion and my observation that DS is now more common in the country than it used to be. Or can it be that I’m only beginning to pay attention to the kids? I recently went for a program in my local church and met a child with this condition. I had innocently claimed a seat behind him before noticing that he had the features of DS. Needless to say, nobody wanted to sit beside that boy and his mother. I felt very sad about it. The Usher had to practically force a man to sit on the remaining seat. So, here are some things we need to know about Down syndrome. 

What is Down Syndrome?

The DNA (Deoxyribonucleic acid) is the unit of life. All characteristics are embedded in these tiny important components of every human being. The DNAs are further packaged into Genes. Genes help in hereditary. They confer what physical attributes a person will have or not. Further down the line, chromosomes are made up of small packs of genes. They occur in pairs in body cells, with the exclusion of our sex cells which do not occur in pairs. So, every human is made up of 46 chromosomes (of 23 pairs), all things being equal.

In children with Down syndrome, a mistake occurs such that there’s an additional copy of the chromosome 21 (a phenomenon called Trisomy). Therefore, children with Down syndrome have 23 pairs + chromosome 21. As a result, the condition is also called Trisomy 21. Because of this error, some features and functions of the body become altered. For instance, children with Down syndrome generally have slower speech development and moderately low Intelligence Quotient (IQ). Regardless of their similar physical and developmental attributes, each child has his/her uniqueness. They also exhibit the general features of DS to varying degrees. Down syndrome is the most common form of chromosomal disorders and survival rate is possible up to 60 years. It is also a known cause of about fifty per cent of spontaneous fetal abortions before 15 weeks in gestation. 

What are these features?

• Flattened face, especially the nose
• Slant almond eyes
• Short stature
• Low muscular tone
• Palmar crease- a line on the palm
• Short neck and ears
• A tongue that sticks out of the mouth

How common is it?

According to the Centres for Disease Control and Prevention (CDC), one of every seven hundred children in the US is born with the condition. Back here in Nigeria, there is no recent statistical data because of poor documentation and birth registration. Nevertheless, research dated as far back as 1982 shows that DS is as common in Nigerians as other races. It is estimated that most children born with Down syndrome die before celebrating their 5th birthday as a result of absent or inadequate early medical interventions. While preparing for the first World Down Syndrome Day in Lagos in 2012, Mrs Mordi of the Down Syndrome Foundation of Nigeria highlighted some crucial points listed below.

• Poor birth registration
• Poor social and medical intervention
• Stigmatisation in the society beginning from close family members
• Poor education facilities for those with Down syndrome

Types of Down Syndrome

There are 3 types although they all have similar physical manifestations.

• Trisomy 21: Found in 95% of DS cases. Here, an extra chromosome 21 is found in the body cells.
• Translocation: Accounts for about 3% of all cases. Here, part or the entire extra chromosome 21 is attached to a different chromosome.
• Mosaic: There’s a mixture in this case that is present in only about 2% of the presented DS. Some body cells have extra chromosome 21 while others don’t. Manifested DS attributes depend on the ratio of the cells with the extra chromosome to those that don’t have. 

Risk factors for Down Syndrome

While there are no known causes of the disorder, some risk factors have been identified.

• Age of the mother: DS is commonly associated with increased maternal age as a result of ageing ovaries. 
• Previous births of DS: The probability of having another child with DS is higher when there’s been a previous birth of DS by a mother. 
• Present translocated chromosome 21 in the mother or father who may only be a carrier.

Can it be inherited?

There is a chance of heredity, but it as low as 5% or less and found in about 1% cases of translocated DS. 

Is there a cure for Down Syndrome?

There are no known cures available for the condition, and it is lifelong. However, steps can be taken to prevent or reduce the risks factors.

• Early birth: Since there is a strong link between a mother’s age and increased probability of having a child with DS, it is advised that women have children before the age of 35. Chances of having a child with DS are as high as 1 in 350 children for women about 35 years old, and 1 in 40 for 45 years and above. 

Early detection: This will inform early medical and social interventions. Prenatal preliminary screening detects or suspects the condition while diagnostic tests help to confirm its presence. Screening tests include sonogram and serum testing while diagnostics include amniocentesis, Percutaneous Umbilical Blood Sampling (PUBS), and Chronic Villus Sampling (CVS). CVS is done in the first trimester while amniocentesis is carried out in the second trimester. Confirmation can be done at birth if DS is suspected in a newborn. Fluorescence In Situ Hybridisation (FISH) and karyotyping are done once physical traits are seen in a neonate.

You can kindly leave your questions in the comment section or send an e-mail to me at xana1611@gmail.com 

#update:Thank you, Dave Adams, for suggesting this link: https://www.wizcase.com/blog/useful-apps-for-kids-with-dyslexia-and-learning-disabilities/ for kids with dyslexia or learning disabilities.

References

Adeyokunnu, A. A. (1982) The incidence of Down’s syndrome in Nigeria. Journal of Medical Genetics, 19:277-279

Christianson, A. (1996) Down syndrome in sub-Saharan Africa. Journal of Medical Genetics, 33:89-92

National Centre on Birth Defects and Developmental Disabilities, Centre for Disease Control and Prevention (2019) Facts about Down Syndrome [online]. Available at https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html (Accessed 28th January, 2020)

National Down Syndrome Society (n.k) Down Syndrome [online]. Available at https://www.ndss.org/about-down-syndrome/down-syndrome/ (Accessed 28^th January, 2020)

Obinna, C. (2012) FG tasked on Down Syndrome children’s death [online]. Available at https://www.vanguardngr.com/2012/03/fg-tasked-on-down-syndrome-childrens-death/ (Accessed 28^th January, 2020)

Poaty, H., Moyen, E., Niama, A. C., Mavoungou, Y.V. (2018) Prevalence and Pattern of Associated Anomalies in Preliminary Working among Congolese Children with Down Syndrome: Analysis of 83 Patients and African Review. Journal of Genetic Disorders, 2:3

Wajuihian, S. O. (2016). Down syndrome: An overview. African Vision Eye Health, 75(1), a346.