Treatment of adrenoleukodystrophy with bone marrow transplantation

Outcomes after allogeneic hematopoietic cell transplantation for childhood cerebral adrenoleukodystrophy: the largest single-institution cohort report

Cerebral adrenoleukodystrophy (cALD) remains a devastating neurodegenerative disease; only allogeneic hematopoietic cell transplantation (HCT) has been shown to provide long-term disease stabilization and survival. Sixty boys undergoing HCT for cALD from 2000 to 2009 were analyzed. The median age at HCT was 8.7 years; conditioning regimens and allograft sources varied. At HCT, 50% demonstrated a Loes radiographic severity score ≥ 10, and 62% showed clinical evidence of neurologic dysfunction. A total of 78% (n = 47) are alive at a median 3.7 years after HCT. The estimate of 5-year survival for boys with Loes score < 10 at HCT was 89%, whereas that for boys with Loes score ≥ 10 was 60% (P = .03). The 5-year survival estimate for boys absent of clinical cerebral disease at HCT was 91%, whereas that for boys with neurologic dysfunction was 66% (P = .08). The cumulative incidence of transplantation-related mortality at day 100 was 8%. Post-transplantation progression of neurologic dysfunction depended significantly on the pre-HCT Loes score and clinical neurologic status. We describe the largest single-institution analysis of survival and neurologic function outcomes after HCT in cALD. These trials were registered at www.clinicaltrials.gov as #NCT00176904, #NCT00668564, and #NCT00383448.

Hematopoietic stem cell transplantation and hematopoietic stem cell gene therapy in X-linked adrenoleukodystrophy

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only therapeutic approach that can arrest cerebral demyelination of X-linked adrenoleukodystrophy (ALD) in boys and results in long-term in a good quality of life, provided the procedure is performed at an early stage of disease. Similar benefits of allogeneic HSCT have been demonstrated in adults with cerebral ALD. However, it is not yet known whether allogeneic HSCT can prevent or rescue adrenomyeloneuropathy. Allogeneic HSCT remains associated with significant morbidity and mortality risks, particularly in adults, and not all ALD patients have donors despite the availability of cord blood. The absence of biological markers that can predict the evolutivity of cerebral disease is a major limitation to propose in due time allogeneic HSCT to ALD patients. Recently, HSC gene therapy using lentiviral vector was shown to have comparable efficacy than allogeneic HSCT in two boys with cerebral ALD who had no Human-leukocyte-antigen (HLA)-matched donor. If these results are confirmed in an extended series of patients, HSC gene therapy may become the first therapeutic option for all ALD male patients who develop cerebral demyelination.

Identification of novel SNPs of ABCD1, ABCD2, ABCD3, and ABCD4 genes in patients with X-linked adrenoleukodystrophy (ALD) based on comprehensive resequencing and association studies with ALD phenotypes

Adrenoleukodystrophy (ALD) is an X-linked disorder affecting primarily the white matter of the central nervous system occasionally accompanied by adrenal insufficiency. Despite the discovery of the causative gene, ABCD1, no clear genotype-phenotype correlations have been established. Association studies based on single nucleotide polymorphisms (SNPs) identified by comprehensive resequencing of genes related to ABCD1 may reveal genes modifying ALD phenotypes. We analyzed 40 Japanese patients with ALD. ABCD1 and ABCD2 were analyzed using a newly developed microarray-based resequencing system. ABCD3 and ABCD4 were analyzed by direct nucleotide sequence analysis. Replication studies were conducted on an independent French ALD cohort with extreme phenotypes. All the mutations of ABCD1 were identified, and there was no correlation between the genotypes and phenotypes of ALD. SNPs identified by the comprehensive resequencing of ABCD2, ABCD3, and ABCD4 were used for association studies. There were no significant associations between these SNPs and ALD phenotypes, except for the five SNPs of ABCD4, which are in complete disequilibrium in the Japanese population. These five SNPs were significantly less frequently represented in patients with adrenomyeloneuropathy (AMN) than in controls in the Japanese population (p=0.0468), whereas there were no significant differences in patients with childhood cerebral ALD (CCALD). The replication study employing these five SNPs on an independent French ALD cohort, however, showed no significant associations with CCALD or pure AMN. This study showed that ABCD2, ABCD3, and ABCD4 are less likely the disease-modifying genes, necessitating further studies to identify genes modifying ALD phenotypes.

Therapy of X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD; OMIM #300100) is caused by defects of the ABCD1 gene on chromosome Xq28, resulting in an impairment of peroxisomal beta-oxidation and the accumulation of saturated very long chain fatty acids (VLCFAs). Primary manifestations occur in the CNS, the adrenal cortex and the testes' Leydig cells. The clinical presentation shows a marked variability which is not explained by the different X-ALD genotypes. Phenotypes range from rapidly progressive cerebral disease with childhood (childhood cerebral ALD [CCALD]) or adulthood (adult cerebral ALD [ACALD]) onset leading to death within a few years, over adult-onset adrenomyeloneuropathy (AMN) with or without focal CNS demyelination, AMN converting into a rapidly progressive, cerebral demyelinating phenotype resembling CCALD, to slow disease progression over decades, or adrenal insufficiency only. Approximately 50% of female heterozygotes develop moderate spastic paresis resembling the AMN phenotype. This review focuses on current experiences with different therapeutic approaches. Lorenzo's oil did not prove to be effective in cerebral inflammatory disease variants, but asymptomatic patients, and speculatively AMN variants without cerebral involvement, as well as female carriers may benefit from early intake of oleic and erucic acids in addition to VLCFA restriction. Hormone-replacement therapy is necessary in all patients with adrenal insufficiency. Hematopoietic stem cell transplantation has been reported to be effective in presymptomatic or early symptomatic CCALD, and may well also be a final therapeutic option in early ACALD patients. Early detection of mutation carriers and timely initiation of therapy is important for the effectiveness of all therapeutic efforts. Gene therapy of endogenous hematopoietic stem cells, pharmacological upregulation of other genes encoding proteins involved in peroxisomal beta-oxidation, reduction of oxidative stress, and possibly lovastatin are candidates for future X-ALD therapies.

Survival analysis of haematopoietic cell transplantation for childhood cerebral X-linked adrenoleukodystrophy: a comparison study

BACKGROUND

Favourable outcomes have been reported for patients with childhood cerebral adrenoleukodystrophy (CCALD) who had received haematopoietic cell transplantation (HCT) at the early stage of cerebral involvement. However, comparative data for non-transplanted CCALD patients are limited. We analysed survival of CCALD patients who had not received HCT and, in a subgroup with early cerebral disease, compared survival in those who underwent HCT with those who did not.

METHODS

Retrospective survival analyses were done on 283 CCALD patients identified at the Kennedy Krieger Institute who had not received HCT, focusing on a 30-member early stage cerebral subgroup whose neurological disability and MRI severity scores matched those in a 19-member transplanted subgroup previously reported. A Kaplan-Meier survival curve and log-rank test were used for survival analysis and to estimate the difference between the survival probabilities of the groups with statistical significance set at alpha=0.05.

FINDINGS

Mean age at onset of symptoms in the entire 283 non-transplanted group was 7 years (SD 2 years). 131 (46%) patients died during the mean follow-up period of 5.9 years (5.3) at a mean age of 12.3 years (4.9). 5-year survival was 66%. The 5-year survival probability of 54% in the early stage group was significantly poorer (chi(2)=7.47, p=0.006) than the 5-year survival of 95% in the transplanted group with early stage cerebral disease.

INTERPRETATION

HCT done in the early and progressive stages of CCALD is beneficial, and our data support the recommendation that transplantation be offered to patients in the early stages of CCALD.

Long-term effect of bone marrow transplantation in adult-onset adrenoleukodystrophy

We report a long-term outcome of motor function in a patient with adult-onset adrenoleukodystrophy after bone marrow transplantation (BMT). Clinically motor function gradually improved and became almost normal in 2 years after BMT. Serial transcranial magnetic stimulation showed gradual improvement of central motor conduction until 1 year after BMT, and then it became stable. Central motor conduction time and motor threshold were useful for monitoring the central motor function in this patient.

Cerebral X-linked adrenoleukodystrophy: the international hematopoietic cell transplantation experience from 1982 to 1999

Cerebral X-linked adrenoleukodystrophy (X-ALD) is a disorder of very-long-chain fatty acid metabolism, adrenal insufficiency, and cerebral demyelination. Death occurs within 2 to 5 years of clinical onset without hematopoietic cell transplantation (HCT). One hundred twenty-six boys with X-ALD received HCT from 1982 to 1999. Survival, engraftment, and acute graft-versus-host disease were studied. Degree of disability associated with neurologic and neuropsychological function and cerebral demyelination were evaluated before and after HCT. Complete data were available and analyzed for 94 boys with cerebral X-ALD. The estimated 5- and 8-year survival was 56%. The leading cause of death was disease progression. Donor-derived engraftment occurred in 86% of patients. Demyelination involved parietal-occipital lobes in 90%, leading to visual and auditory processing deficits in many boys. Overall 5-year survival of 92% in patients with 0 or 1 neurologic deficits and magnetic resonance imaging (MRI) severity score less than 9 before HCT was superior to survival for all others (45%; P <.01). Baseline neurologic and neuropsychological function, degree of disability, and neuroradiologic status predicted outcomes following HCT. In this first comprehensive report of the international HCT experience for X-ALD, we conclude that boys with early-stage disease benefit from HCT, whereas boys with advanced disease may be candidates for experimental therapies.

Two novel mutations in the adrenoleukodystrophy gene in two unrelated Japanese families and the long-term effect of bone marrow transplantation

We identified two novel missense mutations in exon 1 of adrenoleukodystrophy (ALD) gene in two unrelated Japanese families. The first, G(874)C transition results in Arg(163)Pro substitution in the cytoplasmic domain of the ALD protein in adrenomyeloneuropathy family. The second, C(679)G results in Ser(98)Trp substitution in the first transmembrane loop in childhood onset cerebral ALD family. Both mutations cause the substitution of polar amino acid (arginine and serine) with non-polar amino acid (proline and tryptophan). Bone marrow transplantation (BMT) from his non-affected his younger sister was performed on a boy with childhood onset cerebral ALD who showed neurological deficit and brain MRI abnormalities. We evaluated the effect of BMT over a 6-year period in terms of neurological deficit, the level of very-long-chain fatty acids (VLCFA) in plasma and fibroblasts, and brain MRI. After BMT, patient's peripheral white blood cells were replaced by donor's XX ones carrying a normal ALD gene confirmed by in situ hybridization using satellite DNA of the centromere of X and Y chromosomes as probes and the level of VLCFA in lymphocytes was within normal limit. However, his neurological state progressively deteriorated. BMT was not beneficial to him.

Bone marrow transplantation for the treatment of X-linked adrenoleukodystrophy

The effects of bone marrow transplantation (BMT) in X-linked childhood adrenoleukodystrophy (ALD) are described in four Japanese patients. Two older patients, 10-year-old boys with IQ 60 and difficulty in school, had favourable results. IQ levels and MRI findings were generally maintained after BMT. One patient showed improvement of gait disturbance. They have both attended ordinary schools after BMT, although a learning disorder persists. On the other hand, two other younger patients with a rapid course and indeterminate IQ at BMT showed deterioration of neurological functions. Indication for BMT seems to be a maintained IQ level, preferably higher than 80, since it seems to be difficult to normalize IQ level after BMT. Younger patients have higher risk of developing a rapidly progressive form of the disease. Identification of presymptomatic boys, and serial and careful follow-up by neuropsychological and neuroradiological studies, are essential prerequisites to successful BMT in X-ALD.

A child with reading impairment and a family history of adrenoleukodystrophy

The clinical course of a 6-year-old boy with adrenoleukodystrophy (ALD) who underwent allogeneic stem-cell transplantation during an early clinical stage is described. Twenty-three months after transplant, he remains neurologically stable, but with moderate neurological sequelae; the serum very long chain fatty acid profile has improved, but not normalized. The indications, mechanism of action, and complications of bone marrow transplantation in ALD are discussed briefly, along with other potential therapies.

Synthesis of mevalonate pathway lipids in fibroblasts from Zellweger and X-linked ALD patients

Fibroblasts were cultured to determine the involvement of peroxisomes in cholesterol and dolichol synthesis. For this purpose, the behavior of cells from patients with Zellweger syndrome, with X-linked adrenoleukodystrophy, and from nondiseased control subjects was studied. Cells both after pretreatment with mevinolin and without pretreatment were incubated in a medium containing [3H]-mevalonate. In fibroblasts from patients with peroxisomal defects, the cholesterol content and mevalonate incorporation into cholesterol were decreased by 10-20% in comparison with control cells. Mevinolin pretreatment decreased the incorporation rate of [3H]-mevalonate into cholesterol but increased the labeling of ubiquinone and dolichol both in diseased and control cells. Squalene synthase activity was unchanged, whereas the activity of farnesyl-pyrophosphate synthase was increased in the diseased states. The results show that in patients with peroxisomal deficiency neither the amount nor the rate of synthesis of cholesterol and dolichol is reduced to any greater extent.

Neurometabolic disease

Advances in knowledge of neurometabolic disease continues. Of great interest to the neurologist are the definitions of the molecular defects in Niemann-Pick C disease, Refsum disease, and five of the disorders of peroxisome biogenesis, including rhizomelic chondrodysplasia punctata. Duplication of the proteolipid protein gene is the most common molecular abnormality in Pelizaeus Merzbacher disease. Therapies for guanidinoacetate methyltransferase deficiency and for 3-phosphoglycerated dehydrogenase deficiency appear promising. Animal models have been developed for X-linked adrenoleukodystrophy, metachromatic leukodystrophy and Zellweger syndrome and will aid in the understanding of pathogenesis and the evaluation of therapy.

A novel mutation found in an adrenoleukodystrophy patient who underwent bone marrow transplantation

We identified a novel mutation, L322P, in a patient with X-linked adrenoleukodystrophy (ALD) who underwent bone marrow transplantation (BMT). An identification of the ALD gene mutation enabled us to employ an approach not dependent on the use of radioisotopes for detecting mixed chimerism. This assay could show more than 99.0% of the patient's peripheral white blood cells were replaced by the donor's cells.