X-linked Adrenoleukodystrophy in Women: A Cross-Sectional Cohort Study

Brain. 2014 Mar;137(Pt 3):693-706. doi: 10.1093/brain/awt361. Epub 2014 Jan 29.

Abstract

X-linked adrenoleukodystrophy is the most common peroxisomal disorder. The disease is caused by mutations in the ABCD1 gene that encodes the peroxisomal transporter of very long-chain fatty acids. A defect in the ABCD1 protein results in elevated levels of very long-chain fatty acids in plasma and tissues. The clinical spectrum in males with X-linked adrenoleukodystrophy has been well described and ranges from isolated adrenocortical insufficiency and slowly progressive myelopathy to devastating cerebral demyelination. As in many X-linked diseases, it was assumed that female carriers remain asymptomatic and only a few studies addressed the phenotype of X-linked adrenoleukodystrophy carriers. These studies, however, provided no information on the prevalence of neurological symptoms in the entire population of X-linked adrenoleukodystrophy carriers, since data were acquired in small groups and may be biased towards women with symptoms. Our primary goal was to investigate the symptoms and their frequency in X-linked adrenoleukodystrophy carriers. The secondary goal was to determine if the X-inactivation pattern of the ABCD1 gene was associated with symptomatic status. We included 46 X-linked adrenoleukodystrophy carriers in a prospective cross-sectional cohort study. Our data show that X-linked adrenoleukodystrophy carriers develop signs and symptoms of myelopathy (29/46, 63%) and/or peripheral neuropathy (26/46, 57%). Especially striking was the occurrence of faecal incontinence (13/46, 28%). The frequency of symptomatic women increased sharply with age (from 18% in women <40 years to 88% in women >60 years of age). Virtually all (44/45, 98%) X-linked adrenoleukodystrophy carriers had increased very long-chain fatty acids in plasma and/or fibroblasts, and/or decreased very long-chain fatty acids beta-oxidation in fibroblasts. We did not find an association between the X-inactivation pattern and symptomatic status. We conclude that X-linked adrenoleukodystrophy carriers develop an adrenomyeloneuropathy-like phenotype and there is a strong association between symptomatic status and age. X-linked adrenoleukodystrophy should be considered in the differential diagnosis in women with chronic myelopathy and/or peripheral neuropathy (especially with early faecal incontinence). ABCD1 mutation analysis deserves a place in diagnostic protocols for chronic non-compressive myelopathy.

Keywords: X-inactivation; adrenoleukodystrophy; carriers; faecal incontinence; myelopathy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily D, Member 1
  • ATP-Binding Cassette Transporters / genetics*
  • Adrenoleukodystrophy / blood
  • Adrenoleukodystrophy / complications
  • Adrenoleukodystrophy / genetics
  • Adrenoleukodystrophy / physiopathology*
  • Adult
  • Age Factors
  • Aged
  • Cohort Studies
  • Cross-Sectional Studies
  • Evoked Potentials / physiology
  • Female
  • Heterozygote
  • Humans
  • Middle Aged
  • Peripheral Nervous System Diseases / etiology
  • Peripheral Nervous System Diseases / physiopathology*
  • Prospective Studies
  • Spinal Cord Diseases / etiology
  • Spinal Cord Diseases / physiopathology*
  • X Chromosome Inactivation / genetics
  • Young Adult

Substances

  • ABCD1 protein, human
  • ATP Binding Cassette Transporter, Subfamily D, Member 1
  • ATP-Binding Cassette Transporters