What is a Genetic Condition?
A genetic condition is a health problem or illness that happens because of changes in a person’s DNA. Think of DNA like a set of instructions or a recipe book that guides how our bodies grow and function. But unlike a regular book, these instructions can change, and when they do, it can lead to genetic conditions.
What Causes a Genetic Condition?
Genetic conditions occur due to mutations, which are changes in the DNA sequence. These changes can be small, like altering a single letter (A, C, G, or T) in the DNA, or much larger, affecting big sections of DNA or even entire chromosomes. Depending on where and how these mutations happen, they can either be harmless or cause significant issues in how our cells work, leading to a genetic condition.
Some genetic conditions are inherited, meaning they are passed down from parents to their children. Others happen because of mutations that occur during a person’s development or later in life. For example, exposure to harmful things like cigarette smoke or UV rays from the sun can cause changes in DNA, sometimes leading to cancer.
Types of Genetic Conditions
Genetic conditions can be divided into three main categories:
Single Gene Conditions:
- These are caused by changes in just one gene. They often follow clear inheritance patterns.
- Dominant Conditions: A person only needs one mutated gene from one parent to develop the condition. For example, Huntington’s disease.
- Recessive Conditions: A person needs two mutated genes, one from each parent, to have the condition. If they have just one, they’re a carrier, meaning they can pass it to their children. An example is cystic fibrosis.
- X-linked Conditions: These are linked to genes on the X chromosome. Since people with XY chromosomes (typically males) only have one X chromosome, they are more likely to develop these conditions if they inherit a mutated gene. An example is muscular dystrophy.
Chromosome Conditions:
- These result from changes in the number or structure of chromosomes. For instance, Down syndrome occurs when there’s an extra copy of chromosome 21, which is why it’s also known as trisomy 21.
Multifactorial Conditions:
- These are caused by a combination of changes in multiple genes, along with environmental factors. Many cancers fall into this category. For example, certain genetic mutations can increase the risk of bowel cancer, especially when combined with external factors like smoking or certain diets.