The primary objective of the trial is to demonstrate the superiority of biotin at 300 mg/day over placebo in the clinical improvement (walking tests) of patients with adrenomyeloneuropathy

AMN and progressive multiple sclerosis share some similarities including progressive spastic paraparesis and secondary energy failure leading to progressive axonal degeneration. Therefore, it was hypothesized that high doses of biotin might be efficient in patients with AMN.

Inclusion Criteria:

• ABCD1 gene mutation identified
• Elevated plasma VLCFA
• Clinical signs of AMN with at least pyramidal signs in the lower limbs and difficulties to walk
• EDSS score ≥ 3.5 and ≤ 6.5
• Normal brain MRI or brain MRI showing :
• abnormalities that can be observed in AMN patients without cerebral demyelination with a maximum Loes score of 4
• and/or stable (≥6 months) cerebral demyelination without gadolinium enhancement with a Loes score ≤12.
• Appropriate steroid replacement if adrenal insufficiency is present
• Likely to be able to participate in all scheduled evaluation visits and complete all required study procedures
• Signed and dated written informed consent to participate in the study in accordance with local regulations
• Affiliated to a Health Insurance

Exclusion Criteria:

• Brain MRI abnormalities with a Loes score > 12 or with gadolinium enhancement
• Any progressive neurological disease other than AMN
• Impossibility to perform the walk tests and the TUG test
• Patients with uncontrolled hepatic disorder, renal or cardiovascular disease, or any progressive malignancy
• Any new medication for AMN including Fampridine initiated less than 1 month prior to inclusion
• Contra-indications for MRI procedure such as subjects with paramagnetic materials in the body, such as aneurysm clips, pacemakers, intraocular metal or cochlear implants.
• Inclusion in another therapeutic clinical trial for ALD
• Not easily contactable by the investigator in case of emergency or not capable to call the investigator