Adult adrenoleukodystrophy is a X-linked peroxisomal disease associated with the accumulation of very long chain fatty acids (VLCFA) in tissues and body fluids. The diagnosis is established on the demonstration of elevated VLCFA in blood and cultured skin fibroblasts. Women are affected in nearly 15% of cases and neurological symptoms and/or signs develop in 53% of them. Identifying these women is important because of genetic counseling and a possible therapeutic approach. Ten cases of symptomatic heterozygous adult adrenoleukodystrophy are reported. Mean age at the time of diagnosis was 44.6 +/- 9.3 years. All patients presented with spastic paraparesis with inconstant and mild sensory or bladder disturbances. Cognitive impairment was present in 1 case. Cerebrospinal fluid was normal. Adrenal function in response to tetracosactide injection was abnormal in 1/7 cases. Electromyography detected a peripheral neuropathy in 1 case. Somatosensory evoked responses were abnormal in all cases, visual and auditory evoked responses in respectively 3/6 cases and 3/4 cases. Brain MRI detected non specific abnormalities in 3/7 cases; spinal cord MRI was normal in 3/3 cases. The familial history was helpful for the diagnosis in 3/10 cases. Examination of pedigrees detected 5 hemizygous and 1 asymptomatic heterozygous cases. All the patients were enrolled in a dietary study which adret with low VLCFA is currently under evaluation.