It appears that every time we turn on the news, new genetic disorders are being discussed.
But is this because we have improved technology to detect them, or simply that they are on the increase? Before we go any further, what do we mean by genes, DNA, and genetic disorders?
Human beings are made up of millions and millions of cells. Each one of these cells has a function. Some carry blood, some release enzymes so we can digest food, others detect light, and so on. DNA is present in nearly all of these cells.
DNA commands these cells to perform their various functions. A good way to describe DNA is to call it a set of instructions for each cell. So in essence, the cell is the computer and the DNA is the computer programme.
What is our DNA made of?
DNA is a complex molecule shaped like a double helix. It is made up of four different molecules known as bases. It is the order of these four bases in our DNA that form our genes, or genetic code. These genes are contained in our chromosomes.
Each human cell contains 23 pairs of chromosomes, 46 in total. Chromosomes can contain hundreds of thousands of genes.
Your genetic code
Your genetic code makes you who you are. They are instructions passed down from your mother and father. Genetic codes instruct our cells how to make specific proteins. Proteins are used by each cell to perform different functions within our bodies.
Every single gene will determine your distinct features. For instance, there are genes to determine eye and hair colour, height, weight, the shape of the nose, thickness of hair etc.
What causes genetic disorders?
- A defect in one gene
- Mutations in multiple genes
- An addition of an extra gene
- Extra or missing chromosomes
- Chromosomes are moved around or inserted in the wrong places
- Unbalanced chromosome arrangements
Here are the most common genetic disorders in the past:
- Cystic Fibrosis – Cause – Gene mutation
Symptoms from birth, frequent lung infections, persistent coughing, shortness of breath.
- Sickle Cell Anaemia – Cause – Gene mutation
Symptoms present from 5-6 months, this is a blood disorder common in the black community involving abnormal red cells.
- Huntington’s disease – Cause – Gene Defect
Signs of disease from 30-40 years, nerve cells in the brain and nervous system degenerate.
- Down’s syndrome – Cause – Extra chromosome
New-borns show signs of chromosomal abnormalities such as distinctive facial features.
- Celiac Disease – Cause – Genetic mutation
A difficult disease to diagnose, sufferers have an intolerance to gluten and cannot digest any food which contains it.
So why do genetic disorders seem so prevalent today?
Can our DNA be affected by our environment? Can exterior forces influence the very structure of our genes? In order for our DNA to be affected by any influence, it has to be able to change during our lifetime. So is this possible?
Does our DNA change throughout our lifetime?
You would think that our DNA is fixed and immovable. Something as important as our characteristics surely cannot change over our lifetime? Actually, they can. Many of the cells in our bodies that contain DNA are able to divide.
- We grow and need new cells
- Old cells are replaced
- Damaged tissue is repaired
Whenever a cell divides, the DNA replicates to form two copies of each chromosome. It is during mitosis that our DNA can change.
What can change our DNA and lead to Genetic Disorders?
There are many things that can change our DNA. Radiation, gamma, and x-rays can degrade and disrupt DNA.
Here are five factors that disrupt DNA:
- Mobile Phone Radiation
- Pesticides & Fertilizer
Pesticides and fertilizers contain harmful chemicals as they have to destroy insects. They also have a detrimental effect on DNA. Studies have shown exposure can cause mutated DNA that affects reproduction.
Foods covered in plastic can leach chemicals which we know are harmful. But they also change our DNA. Similar to pesticides, chemicals can cause mutations.
So are Genetic Disorders more common today?
Now we know what genes and genetic disorders are and that DNA can change during our lifetime. So are we any closer to discovering whether genetic disorders are more common? As a matter of fact, yes.
This could be because of an increase in those very genetic disorders. Thanks to modern medicine and advances in agriculture, hunter gathers are no longer needed.
As well as modern lifestyles, humans are living longer and genetic disorders that would be fatal hundreds of years ago, are no longer death sentences. In addition, as more people are living longer, it is more likely that our genes are being passed on. This includes faulty genes.
Another reason for an increase in genetic disorders is that older parents are now having children. There is a much higher risk that older people will have a child with a developmental disorder caused by a gene mutation. To give you some idea:
- Risks for parents in their 20’s is 1 in 450
- Risks for parents in their mid-forties is 1 in 210
Researchers used their data to calculate the following: Of the 140 million births globally they estimate that around 400,000 will now have a developmental disorder. This disorder is due to a mutation in the genes.
So the evidence points to several reasons for genetic disorders to be common today.
- People are no longer dying from genetic disorders
- People are living longer to pass on their genes
- Older people are having children
So what sort of genetic disorders are we talking about?
There are several disorders in children that are now attributed to genes. For instance, ADHD is now recognised to have chromosomal deletions and duplications similar to other neurodevelopmental disorders.
One study discovered 14 new developmental disorders. Moreover, these new mutations linked to other developmental disorders the study team already knew about.
It was estimated that for 42% of the children a new mutation in a gene was likely to be the underlying cause of their condition. This gene is essential for healthy development. Additionally, the study also estimated that around 1 in 300 UK children have a rare developmental disorder caused by a new mutation. That’s around 2,000 UK children a year.
The problem is that when children are affected at such an early age, they are more likely to pass on faulty genes to their offspring.
Do you worry that genetic disorders are on the increase? There is genetic testing that can tell you if you have a particular genetic disorder. Furthermore, you can limit your exposure to environmental factors that cause changes in your DNA.
In conclusion, genetic disorders might be more common, but medical advances are improving every day.
By Janey D.