Nerve experts examine finger length

A long ring finger may indicate a heightened risk of motor neurone disease, research suggests.

The link is thought to be due to pre-birth levels of the male hormone testosterone in the womb.

High prenatal exposure to testosterone could make adult motor nerves less sensitive to the hormone, say scientists. Hormones in the womb are believed to affect relative ring and index finger length, known as 2D:4D ratio.

A low ratio means the ring finger is relatively long compared with the index finger, which is more often the case in men.

The new research suggests that a low 2D:4D ratio is also associated with the most common form of motor neurone disease, amyotrophic lateral sclerosis (ALS).

The normally fatal disease causes progressive degeneration of the motor nerves that control movement, as well as weakness and muscle wasting.

Leading physicist Professor Stephen Hawking is one of the best known sufferers of the condition.

Researchers writing in the Journal of Neurology, Neurosurgery and Psychiatry compared 47 ALS patients and 63 healthy individuals.

Although no overall difference in 2D:4D ratio was seen between men and women, it was consistently lower for people with ALS.