Overview
X-linked adrenoleukodystrophy (X-ALD) is a genetic peroxisomal disorder characterized by the accumulation of very long chain fatty acids (VLCFAs), leading to diverse clinical manifestations including cerebral demyelination, spasticity, and dystonia primarily affecting males 123.Diagnosis
Measurement of VLCFAs in plasma or leukocytes is diagnostic 13.
Prenatal diagnosis can be enhanced by assessing ALDP expression alongside VLCFA levels in chorionic villi and amniotic fluid cells 4.
Distinguishing from peroxisomal biogenesis disorders (PBD) and single-enzyme deficiencies (SED) requires clinical presentation and biochemical markers 3.Management
First-line treatments:
- Allogeneic hematopoietic stem cell transplantation (HSCT) is curative if performed early 2.
Adjunctive treatments:
- Intrathecal baclofen for severe spasticity and dystonia unresponsive to oral medications 1.
- Exploration of retinoids to upregulate ABCD2 as a potential anti-inflammatory and metabolic compensatory strategy 2.Special Populations
Prenatal Diagnosis: Utilize ALDP expression analysis alongside VLCFA measurements to improve accuracy 4.
Pediatrics: Early onset cerebral X-ALD requires urgent intervention, ideally HSCT 3.Key Recommendations
Consider allogeneic hematopoietic stem cell transplantation early in the course of cerebral X-ALD for curative potential (Evidence: Strong 2).
Implement intrathecal baclofen therapy for management of severe spasticity and dystonia unresponsive to oral medications (Evidence: Weak 1).
Explore pharmacological upregulation of ABCD2 using retinoids as a novel adjunctive treatment approach to halt disease progression (Evidence: Moderate 2).References
1 Hjartarson HT, Ehrstedt C, Tedroff K. Intrathecal baclofen treatment an option in X-linked adrenoleukodystrophy. European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2018. link
2 Weber FD, Weinhofer I, Einwich A, Forss-Petter S, Muneer Z, Maier H et al.. Evaluation of retinoids for induction of the redundant gene ABCD2 as an alternative treatment option in X-linked adrenoleukodystrophy. PloS one 2014. link
3 Corzo D, Gibson W, Johnson K, Mitchell G, LePage G, Cox GF et al.. Contiguous deletion of the X-linked adrenoleukodystrophy gene (ABCD1) and DXS1357E: a novel neonatal phenotype similar to peroxisomal biogenesis disorders. American journal of human genetics 2002. link
4 Ruiz M, Coll MJ, Pampols T, Girós M. ALDP expression in fetal cells and its application in prenatal diagnosis of X-linked adrenoleukodystrophy. Prenatal diagnosis 1997. link