Summary: Key Takeaways
Mould can make some people ill for years because of toxic substances called mycotoxins.
Your genes affect how well your body removes these toxins—some people’s bodies struggle to get rid of them.
More than 25% of people in the UK may have HLA-DR/DQ gene variations that slow down mycotoxin detoxification, making them more vulnerable to long-term mould-related illnesses (source).
A new study confirms that people with these genes may continue to feel unwell long after leaving a mouldy home (Saghir & Ansari, 2024).
One person in the study still had toxins in their system 18 months later, and it could take years to fully clear out.
Climate change is making mould problems worse, meaning more people may be affected in the future.
Doctors should check for genetic risk factors when people have long-term symptoms after mould exposure.
Mould and Your Body: Why Some People Stay Ill for Years
Mould is something most people have seen at home—maybe in a damp bathroom or on a forgotten slice of bread.
But for some people, mould isn’t just an annoyance; it can make them ill for years.
This happens because mould releases mycotoxins, toxic substances that can harm the body.
Most people’s bodies can naturally remove these toxins, but some people’s bodies struggle to do so.
This is due to their genes, specifically, something called HLA-DR/DQ alleles.
If someone has these genes, their body holds onto mycotoxins for much longer, which can lead to long-term health problems.
In the UK, more than 25% of people may carry these genetic variations, making them more vulnerable to persistent mould-related illnesses (source).
A new study by Saghir & Ansari (2024) (link) examined four people with these genetic variations who were exposed to mould in their homes.
Even after moving out, they still felt ill.
The reason? Their bodies couldn’t get rid of the mycotoxins quickly enough.
Real Stories: How Mould Exposure Lasts for Years
The Saghir & Ansari (2024) study found that individuals with HLA-DR/DQ variations struggle to detoxify mycotoxins, leading to long-term health effects.
One person had two urine tests taken 18 months apart, and they still had high levels of mycotoxins in their system.
It was estimated that it could take more than four years for their body to fully clear out one of the toxins.
A family lived in a mouldy house for four years, then moved away.
Even two years later, their tests showed that mycotoxins were still in their bodies.
This slow detox process was up to 213 times slower than in people without these genetic traits!
That means even a short time in a mouldy home could turn into a long-term health problem for some people.
Why This Matters for the Future
The problem is getting worse.
Climate change—with rising temperatures, humidity, and CO₂ levels—means that mould will become more common in homes.
This could lead to more people being exposed to mycotoxins and suffering long-term effects.
Doctors and scientists say we need to:
Test for genetic risks in people with long-term symptoms.
Improve mould prevention in homes (better ventilation, reducing dampness).
Raise awareness so people understand the dangers of long-term mould exposure.
Mould isn’t just a household nuisance – for some people, it’s a serious health risk that can last for years.
If someone continues to feel unwell after being in a mouldy environment, their genes could be the reason why.
For more details, read the full study by Saghir & Ansari (2024) here.
