Inherited Diseases23 January, 2019
Inherited diseases are also known as genetic disorders; and since genes are passed down from parent to child, any mutations or changes in the DNA will also be passed onto the child. This is called ‘running in the family’ and refers to situations when more than one member of the family has the same condition. There are three types of genetic disorders –
- Single-gene disorder – where one gene is affected by the mutation.
- Chromosomal disorder – where chromosomes or parts of chromosomes are missing.
- Complex disorders – where mutations occur on two or more genes.
But first, what are genes you might want to know – they are segments of DNA alphabets which when read correctly, go on to provide specific instructions for the body to function normally. And it’s estimated that there are at least 22,000 genes in the genome and they all have a specific location on the chromosomes that you inherit from your parents. And since you have two parents, you end up with two copies of each gene – which characteristic manifests in you will depend on the dominance of that gene. Not only that, any mutations on that gene also get passed onto you, leading to a specific genetic disorder.
The current dilemma being faced by scientists is on elucidating how genes contribute towards inheritance of diseases like diabetes, asthma and cancer since they have a complex pattern of inheritance. It is likely that a number of genes might be affected and contributes towards susceptibility to such diseases – along with the inherent environmental factors.
Another question is why do inherited diseases appear only some of the time? If the DNA mistake is present on a dominant gene, there is a 50-50 chance that your child will also inherit the disorder, as the child inherits a set of two genes from both parents. But if the genetic mutation is on a recessive (non-dominant) gene, then your child only has a 25% chance of inheriting the disease as both parents will need to have the same mutation in their DNA.
Researchers estimate that most people are walking around with at least 6-10 recessive gene changes and don’t even know about it – as there are no symptoms to be displayed.
This makes it essential that you go through your own and your spouse’s familial histories to determine the chances of your having a child with similar inheritable disease conditions – a prepared mind is always better so that you know what the risks are, and whether they are worth it.