Adrenoleukodystrophy (ALD) is a type of congenital dysmyelinating disease. It carries an X linked inheritance.
The estimated incidence is at around 1 : 20000-50000. Due to its X linked inheritance it classically affects young males.
The conditions results from an accumulation of very long chain fatty acids (VLCFAs) from a genetic deficiency in peroxisomal oxidation of fatty acids. This is thought to result from a mutation in a ALDP gene located on Xq28 5. The cerebral white matter is typically split into three different zones:
- central (inner) zone - irreversible gliosis and scarring
- intermediate zone - active inflammation and breakdown of the blood-brain barrier
- peripheral (outer) zone - leading edge of active demyelination
There are five main phenotypes 3
- childhood cerebral
- adolescent cerebral
- adult cerebral
- limited to Addison's disease
Some individuals can be asymptomatic.
A majority of cases tend to show symmetrical cerebral white matter signal change involving the posterior periventricular white matter (i.e. posterior cerebral, around splenium and peritrigonal white matter). Signal changes can vary according to the zonal distribution within the affected white matter. There is relative sparing of sub-cortical u fiber involvement.
- central zone - hypo intense
- intermediate zone - ?
- peripheral zone - ?
- T1 C+ (Gd) - enhancement seen in ~ 50% of cases according to one study and is thought to be associated with disease progression 6. With contrast infusion, serpiginous, garland-shaped enhancement may be visible in the anterior most periphery of the lesions.7
- central zone - markedly hyper intense
- intermediate zone - iso to hypo intense
- peripheral zone - moderately hypo intense
May show evidence of neuronal loss manifested by a decease in the NAA peak and an elevation in the lactate peak
Treatment and prognosis
Bone marrow transplantation is thought to be favourable in the early stages of disease. Restriction of very long chain fatty acids (VLCFAs) has also been trialled.
Differential consideration for the classic pattern include:
It is thought to be initially described by Siemerling and Creutzfeld in 19231.
- 1. Victor M, Ropper AH, Adams RD. Adams and Victor's principles of neurology. McGraw-Hill Professional. (2001) ISBN:0070674973. Read it at Google Books - Find it at Amazon
- 2. Bizzi A, Castelli G, Bugiani M et-al. Classification of childhood white matter disorders using proton MR spectroscopic imaging. AJNR Am J Neuroradiol. 2008;29 (7): 1270-5. doi:10.3174/ajnr.A1106 - Pubmed citation
- 3. Moser HW. Adrenoleukodystrophy: phenotype, genetics, pathogenesis and therapy. Brain. 1997;120 ( Pt 8) (8): 1485-508. doi:10.1093/brain/120.8.1485 - Pubmed citation
- 4. Inoue Y, Fukuda T, Takashima S et-al. Adrenoleukodystrophy: new CT findings. AJNR Am J Neuroradiol. 4 (4): 951-4. AJNR Am J Neuroradiol (abstract) - Pubmed citation
- 5. Cheon JE, Kim IO, Hwang YS et-al. Leukodystrophy in children: a pictorial review of MR imaging features. Radiographics. 22 (3): 461-76. Radiographics (full text) - Pubmed citation
- 6. Melhem ER, Loes DJ, Georgiades CS et-al. X-linked adrenoleukodystrophy: the role of contrast-enhanced MR imaging in predicting disease progression. AJNR Am J Neuroradiol. 2000;21 (5): 839-44. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 7. Haaga JR, Boll D. CT and MRI of the whole body. Mosby. (2009) ISBN:0323053750. Read it at Google Books - Find it at Amazon
Synonyms & Alternative Spellings
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|X linked adrenoleukodystrophy||✓|
|X linked adrenoleukodystrophy (ALD)||✗|