Pointing the finger towards the causes of MND

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Would it ever cross your mind that the relative lengths of your fingers might be related to the durability of your motor neurones? Probably not – at first glance the link seems extraordinarily tenuous! However, a research group led Prof Ammar Al-Chalabi, who has close connections with the Association, has found that people with MND tend to have relatively long ring fingers.

So what? Well the results of this study, published this week, do in fact provide some important clues about events occurring before a person is even born that might predispose them to getting MND. For both men and women, exposure to relatively high testosterone levels during development in the womb is associated with having a relatively long ring finger compared to index finger in adulthood. Research has already indicated that testosterone might influence motor neurone health, and increased testosterone exposure in the womb is also linked to male sex and athletic prowess, both of which may be connected with a slightly higher risk of MND.

Prof Al-Chalabi’s team therefore took an extremely simple but ingenious approach to finding out that men and women exposed to higher levels of testosterone during their development as a foetus might be more likely to get MND as adults. Although their results will need confirming in larger studies, they are a reminder of how very subtle factors that might start accumulating before a person is even born, let alone during their childhood or early adulthood, can start to tip the balance towards the development of MND in middle age or later.

Most people with MND are likely to ask themselves ‘Why me?’ and it’s very tempting to look for answers in events immediately preceding diagnosis. The results of this study support the idea that some risk factors may have occurred well before a person could possibly have any memory of them!

More information on what this study means for MND research and people affected by the disease is available in our press release.

Download the official lay article from the BMJ

Article reference: Vivekananda U, Manjalay Z-R, Ganesalingam J et al. Low index-to-ring finger length ratio in sporadic ALS supports prenatally defined motor neuronal vulnerability. Online First J Neurol Neurosurg Psychiatry 2011; doi:10.1136/jnnp.2010.237412