Since publication of this article in the May 2012 issue of Amyotrophic Lateral Sclerosis, an error has been identified in the first full paragraph on page 253.
The first sentence of this paragraph was published as:
‘Within a family, the sibling that went on to develop ALS may have had higher levels of prenatal testosterone exposure and so have a higher 2D:4D ratio than their siblings.’
This should have read:
‘Within a family, the sibling that went on to develop ALS may have had higher levels of prenatal testosterone exposure and so have a lower 2D:4D ratio than their siblings.’