Group C: peroxisomal disorders characterized by the loss of only a single peroxisomal enzyme activity

Adrenomyeloneuropathy (AMN) is the second most commonly observed phenotype of adrenoleukodystrophy, occurring in 21% of the 409 cases analysed by Moser H.W. et al. (1987) with primary involvement of the spinal cord and peripheral nerves. Other forms of the disease include adolescent ALD (10%), adult cerebral ALD (3%), Addison disease only without neurologic involvement (7%), and those individuals without overt clinical symptoms but showing the biochemical abnormality (Moser H.W. et al., 1987). Importantly, about 20% of females heterozygous for ALD show symptomatology.