How Much Of MND Is Inherited?

For the majority of people who develop MND, their genes play a very minor role in contributing towards the chances of developing MND. For a small percentage of people, who have the rare familial form of the disease, their genetic make up may be more significant.

There are two aspects to genetic research in MND: One of these is to discover genes that cause the rare, familial form of MND; the other is to identify genes that may increase the risk of developing the more comon sporadic form of the disease.

Genes that cause familial MND

In around 5 - 10% of cases, MND is directly caused by a mistake in a gene. This mistake can be passed down from parent to child. 

The inherited form of MND is rare but can be devastating for families affected by it. More information on the issues surrounding familial MND is available in Research info sheet B - Inherited MND (87 kb) .

In the 1990s, scienitists identified the faulty gene that accounts for around 20% of these rare cases of inherited MND. This gene is called SOD1. Other faulty genes that cause the disease have since been identified, but they account for a tiny number of cases. However, the discovery of these genes can provide clues as to how motor neurones are damaged in MND and may advance our understanding of all types of the disease. More information is available from Research info sheet C - Genetics & familial MND (84 kb)


Genetic risk factors in 'sporadic MND'

For the most common 'sporadic' form MND, subtle variations in certain genes are thought to contribute to the chances of developing MND through a combination of particular genetic characteristics and environmental factors. These genes are sometimes known as susceptibility genes. Whilst certain variations in these genes may slightly increase the risk of a person getting MND, they do not on their own cause the disease. Sporadic MND is not passed from parent to child.

The identification of susceptibility genes could provide clues to the underlying mechanisms of MND. The Association has funded a "whole genome scan" research project that uses new technology to hunt for these genes.

Other news about susceptibility genes can be found in the following articles: