Amyotrophic lateral sclerosis: a hormonal condition?

Amyotrophic lateral sclerosis (ALS) is the most frequent motor neuron disorder in adults. This fatal condition, due to degeneration of upper and lower motor neurons in spinal and bulbar myotomes, leads to death from respiratory failure after median disease duration of 36 months. ALS is sporadic in more than 90% of cases and familial in the remaining cases. Most studies show male predominance with a gender ratio of 3:2, but gender differences are age related. The phenotype of ALS is also different in males and females with a predominance of limb onset in males and bulbar onset in females. While age and site of onset impact survival rate, and are both related to gender, gender by itself has not clearly been shown to have an effect on survival. Given this complex relationship between gender and ALS, we developed a hypothesis about hormone involvement in ALS aetiology by suggesting protective effect of oestrogens and adverse effect of androgens.