Therapeutic strategies in adrenoleukodystrophy

Nutritional status of children affected by X-linked adrenoleukodystrophy

BACKGROUND

Adrenoleukodystrophy (ALD) is a rare X-linked metabolic disorder that causes the accumulation of very-long-chain fatty acids (VLCFAs) (C26:0) and the subsequent variety of clinical and neurological symptoms. Little is known about nutritional status and dietary habits of children affected by ALD, and so the present study aimed to assess nutritional status and food intake in children with ALD, also exploring the relationship between food intake and the consumption of disease-specific dietary supplements to reduce blood C26:0 concentrations and increase monounsaturated fatty acids (C26:1).

METHODS

All patients underwent a clinical and neurological evaluation and a comprehensive nutritional assessment. The association of VLCFA concentrations with dietary lipids was assessed.

RESULTS

Nine boys (11.49 ± 3.61 years) were enrolled in a cross-sectional study. All patients were normal weight, with normal resting energy expenditure. Only six of nine patients followed the low-fat diet and dietary supplements. An inverse association was found between the food intake of polyunsaturated lipids and C26:0; conversely, the C26:0 was positively associated with the dietary saturated lipids. When consumed, dietary supplement consumption correlated positively with C26:1 (ρ = 0.917, p = 0.029) and no correlation was found with C26:0 (ρ = 0.410, p = 0,493).

CONCLUSIONS

No children were found to be malnourished or overweight or obese; however, half of the children reported excessive body fat, probably as a result of the pharmacotherapies. A low-fat diet could be adjuvant in the management of the accumulation of VLCFAs, but poor dietary compliance to disease-specific nutritional guidelines appears to be a major problem of this condition and underlines the need for a structured and personalised nutritional management in ALD disease.

Unrelated umbilical cord blood transplantation for children with hereditary leukodystrophy: A retrospective study

Objective

To analyze the efficiency of unrelated umbilical cord blood transplantation (UCBT) in the treatment of hereditary leukodystrophy following busulfan- and cyclophosphamide-based myeloablative chemotherapy.

Methods

A retrospective study was performed in patients with hereditary leukodystrophy who underwent UCBT after myeloablative chemotherapy between April 2015 and March 2020.

Results

The study cohort included 12 pediatric patients (ten males), nine with cerebral adrenoleukodystrophy (ALD) and three with juvenile globoid cell leukodystrophy (GLD). All received HLA-matched or partially mismatched unrelated UCBT. There were no cases of graft rejection. Median neutrophil engraftment time was 20 days [12–33 days] and median platelet engraftment time was 29 days [14–65 days]. Median follow-up was 36 months [1–86 months], and the overall survival rate for patients with cerebral ALD and juvenile GLD after UCBT was 77.8% (7/9) and 100% (3/3), respectively. In patients with ALD, although lipid profiles (serum very-long-chain fatty acid) were improved post-UCBT, six patients demonstrated worse neurologic function score and performance status post-UCBT, and six patients had higher Loes scores at last follow-up compared with baseline. In patients with juvenile GLD, all patients showed stable neurologic function score and performance status despite the Loes score of one patient increased slightly after transplantation.

Conclusion

In patients with cerebral ALD, patients with no or mild neurological symptoms can benefit from UCBT, while UCBT cannot reverse advanced disease. In patients with juvenile GLD, UCBT is safe and contributes to stabilize neurological function.

Pediatric Primary Adrenal Insufficiency: A 21-year Single Center Experience

OBJECTIVE

Primary adrenal insufficiency (PAI) is a rare but potentially life-threatening condition. In childhood, PAI is usually caused by monogenic diseases. Although congenital adrenal hyperplasia (CAH) is the most common cause of childhood PAI, numerous non-CAH genetic causes have also been identified.

METHODS

Patients aged 0-18 years and diagnosed with PAI between 1998 and 2019 in a tertiary care hospital were retrospectively evaluated. After the etiologic distribution was determined, non-CAH PAI patients were evaluated in detail.

RESULTS

Seventy-three PAI patients were identified. The most common etiology was CAH (69.9%, n=51). Non-CAH etiologies accounted for 30.1% (n=22) and included adrenoleukodystrophy (ALD; n=8), familial glucocorticoid deficiency (n=3), Triple A syndrome (n=5), autoimmune adrenalitis (n=1), adrenal hypoplasia congenital (n=1), IMAGe syndrome (n=1), and other unknown etiologies (n=3). The median age at the time of AI diagnosis for non-CAH etiologies was 3.52 (0.03-15.17) years. The most frequent symptoms/clinical findings at onset were hyperpigmentation of skin (81.8%), symptoms of hypoglycemia (40.9%), and weakness/fatigue (31.8%). Hypoglycemia (50.0%), hyponatremia (36.4%) and hyperkalemia (22.7%) were prominent biochemical findings. Diagnosis of specific etiologies were proven genetically in 13 of 22 patients. A novel p.Q301* hemizygous frameshift mutation of the DAX1 gene was identified in one patient.

CONCLUSION

Etiology was determined in 86.3% of children with non-CAH PAI through specific clinical and laboratory findings with/ without molecular analysis of candidate genes. ALD was the most common etiology. Currently, advanced molecular analysis can be utilized to establish a specific genetic diagnosis for PAI in patients who have no specific diagnostic features.

X-linked adrenoleukodystrophy caused by a novel mutation presenting with various phenotypes in a Taiwanese family

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder that primarily affects the white matter of central nervous system and the adrenal cortex. It is caused by mutations in the adenosine triphosphate-binding cassette, subfamily D, member 1 (ABCD1) gene that results in elevated plasma levels of very long chain fatty acids (VLCFAs). The disease is characterized by an unpredictable variation in phenotypic expressions, including childhood cerebral form (CCALD) and adrenomyeloneuropathy (AMN). Genetic analysis is a reliable method for the diagnosis of X-ALD. We reported a 46-year-old male admitted to Department of Neurology, Chang Gung Memorial Hospital with progressive paraparesis and Addison's disease, which was diagnosed when he was around 20-year-old. Plasma levels of VLCFA showed that his C26:0, C24:0/C22:0 and C26:0/C22:0 ratios were significantly elevated. A novel missense mutation (p.Arg163Cys) caused by the nucleotide change c.487C > T in exon 1 was identified in the ABCD1 gene of the proband and his subclinical family members. In this article, we reviewed the mutations that had been reported at the same position with different phenotypes. Given that the nerve conduction study (NCS) of the proband demonstrated a rare finding of demyelinating polyneuropathy with conduction blocks, we also reviewed the findings of NCS in patients with AMN in literature.

Molecular Biomarkers in Multiple Sclerosis and Its Related Disorders: A Critical Review

Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system (CNS) which can lead to severe disability. Several diseases can mimic the clinical manifestations of MS. This can often lead to a prolonged period that involves numerous tests and investigations before a definitive diagnosis is reached. As well as the possibility of misdiagnosis. Molecular biomarkers can play a unique role in this regard. Molecular biomarkers offer a unique view into the CNS disorders. They help us understand the pathophysiology of disease as well as guiding our diagnostic, therapeutic, and prognostic approaches in CNS disorders. This review highlights the most prominent molecular biomarkers found in the literature with respect to MS and its related disorders. Based on numerous recent clinical and experimental studies, we demonstrate that several molecular biomarkers could very well aid us in differentiating MS from its related disorders. The implications of this work will hopefully serve clinicians and researchers alike, who regularly deal with MS and its related disorders.

A report on state-wide implementation of newborn screening for X-linked Adrenoleukodystrophy

Minnesota became the fourth state to begin newborn screening (NBS) for X‐linked adrenoleukodystrophy (X‐ALD) in 2017. As there is limited retrospective data available on NBS for X‐ALD, we analyzed Minnesota's NBS results from the first year of screening. C26:0 lysophosphatidylcholine (C26:0‐LPC) screening results of 67,836 infants and confirmatory testing (ABCD1 gene and serum VLCFA analysis) for screen positives were obtained. Fourteen infants (nine males, five females) screened positive for X‐ALD and all were subsequently confirmed to have X‐ALD, with zero false positives. The birth prevalence of X‐ALD in screened infants was 1 in 4,845 and 1 in 3,878 males, more than five times previous reported incidences. Pedigrees of affected infants were analyzed, and 17 male (mean age of 17) and 24 female relatives were subsequently diagnosed with X‐ALD. Phenotypes of these family members included self‐reported mild neuropathy symptoms in two males and seven females, and childhood cerebral disease (ccALD) and adrenal insufficiency in one male. We observed fewer cases of ccALD and adrenal insufficiency than expected in male family members (5.9% of males for both) compared to previous observations. Together, these findings suggest that the spectrum of X‐ALD may be broader than previously described and that milder cases may previously have been underrepresented. Other challenges included a high frequency of variants of uncertain significance in ABCD1 and an inability to predict phenotypic severity. We posit that thoughtful planning to address these novel challenges and coordination by dedicated specialists will be imperative for successful implementation of population‐based screening for X‐ALD.

Allogeneic hematopoietic stem cell transplantation with myeloablative conditioning for adult cerebral X-linked adrenoleukodystrophy

The adult cerebral form of X-linked adrenoleukodystrophy (ACALD), an acute inflammatory demyelinating disease, results in a rapidly progressive neurodegeneration, typically leading to severe disability or death within a few years after onset. We have treated 15 men who had developed ACALD with allogeneic hematopoietic stem cell transplantation (HSCT) from matched donors after myeloablative conditioning with busulfan and cyclophosphamide. All patients engrafted and 11 survived (estimated survival 73 ± 11%), 8 with stable cognition and 7 of them with stable motor function (estimated event-free survival 36 ± 17%). Death after transplantation occurred within the first year after HSCT and was caused either primarily by infection (N = 3) or due to disease progression triggered by infection (N = 1). Patients with minor myelopathic symptoms (N = 4) or with no or mild cerebral symptoms pre-transplant (N = 7) had an excellent outcome. In contrast, no patient with major neurological symptoms associated with an extensive involvement of pyramidal tract fibres in the internal capsule (N = 5) survived without cognitive deterioration. Notably, early leukocyte recovery was associated with dismal outcome for yet unknown reasons. All 10 tested survivors showed a reduction of plasma hexacosanoic acid (C26:0) in the absence of Lorenzo's oil. Over time, the event-free survival could be improved from 2 out of 8 patients (25%) before 2013 to 5 out of 7 patients (71%) thereafter. Therefore, allogeneic HSCT appears to be a suitable treatment option for carefully selected ACALD patients when transplanted from matched donors after myeloablative, busulfan-based conditioning.

Late onset adrenoleukodystrophy: A review related clinical case report

Our objective is to review the initial presentation, evolution, progression, final stage, and images in the follow up of an adult patient who presented an uncommon peroxisomal disease (1/20,000 males) that occurred by ABCD1 gene mutation in the Xq28 chromosome; to bring forward the imaging features (which nowadays is the most useful and accessible diagnostic tool) and clinical presentation of adrenoleukodystrophy in adulthood; to propose a differential diagnosis in aid of a prompt recognition of the disease hereafter from a neurologist approach. In relation of a clinical case we reviewed the literature to correlate the principal findings and evolution of the disease. This thrilling but at the same time unfortunate disease is not only a diagnostic problem is also a therapeutic quest besides all the related familial, labor, and social related problems. The very-long chain fatty acids (VLCFA) accumulation leads to a not completely understood mechanisms that precipitate the specific malfunction of the nervous system and adrenal gland. The initial corticospinal bilateral involvement provokes a spastic paraparesis but with the affection of others pathways multiple manifestations appears, with dementia and finally loss of the most of cortical functions secondary to the white matter affection. Since the hematopoietic stem cell transplantation can be treated with variable results, other treatments, as the Lorenzo's oil, have not been consistent with a substantial improvement of the affected individual. The genetic advice and support to the patient and the family are essentials as well as the screening in individuals at risk before the onset of the disease.

Economic impact of screening for X-linked Adrenoleukodystrophy within a newborn blood spot screening programme

BACKGROUND

A decision tree model was built to estimate the economic impact of introducing screening for X-linked adrenoleukodystrophy (X-ALD) into an existing tandem mass spectrometry based newborn screening programme. The model was based upon the UK National Health Service (NHS) Newborn Blood Spot Screening Programme and a public service perspective was used with a lifetime horizon. The model structure and parameterisation were based upon literature reviews and expert clinical judgment. Outcomes included health, social care and education costs and quality adjusted life years (QALYs). The model assessed screening of boys only and evaluated the impact of improved outcomes from hematopoietic stem cell transplantation in patients with cerebral childhood X-ALD (CCALD). Threshold analyses were used to examine the potential impact of utility decrements for non-CCALD patients identified by screening.

RESULTS

It is estimated that screening 780,000 newborns annually will identify 18 (95%CI 12, 27) boys with X-ALD, of whom 10 (95% CI 6, 15) will develop CCALD. It is estimated that screening may detect 7 (95% CI 3, 12) children with other peroxisomal disorders who may also have arisen symptomatically. If results for girls are returned an additional 17 (95% CI 12, 25) cases of X-ALD will be identified. The programme is estimated to cost an additional £402,000 (95% CI £399-407,000) with savings in lifetime health, social care and education costs leading to an overall discounted cost saving of £3.04 (95% CI £5.69, £1.19) million per year. Patients with CCALD are estimated to gain 8.5 discounted QALYs each giving an overall programme benefit of 82 (95% CI 43, 139) QALYs.

CONCLUSION

Including screening of boys for X-ALD into an existing tandem mass spectrometry based newborn screening programme is projected to reduce lifetime costs and improve outcomes for those with CCALD. The potential disbenefit to those identified with non-CCALD conditions would need to be substantial in order to outweigh the benefit to those with CCALD. Further evidence is required on the potential QALY impact of early diagnosis both for non-CCALD X-ALD and other peroxisomal disorders. The favourable economic results are driven by estimated reductions in the social care and education costs.

Potential Risks to Stable Long-term Outcome of Allogeneic Hematopoietic Stem Cell Transplantation for Children With Cerebral X-linked Adrenoleukodystrophy

IMPORTANCE

Allogeneic hematopoietic stem cell transplantation is the standard intervention for childhood cerebral X-linked adrenoleukodystrophy. However, the pretransplant conditions, demyelination patterns, complications, and neurological outcomes of this therapy are not well characterized.

OBJECTIVES

To identify the risks to stable neurocognitive survival after hematopoietic stem cell transplantation and to describe subgroups of patients with distinct clinical long-term outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This case series analyzed the treatment and outcome of a cohort of 36 boys who underwent hematopoietic stem cell transplantation at Charité Universitätsmedizin Berlin, Germany, between January 1, 1997, and October 31, 2014. Case analysis was performed from January 1, 2016, through November 30, 2017. During this retrospective review, the adrenoleukodystrophy-disability rating score and the neurological function score were used. Demyelinating lesions in the brain were quantified by the Loes score.

MAIN OUTCOMES AND MEASURES

Overall survival, survival without major functional disabilities, and event-free survival were analyzed. Patients' clinical symptoms, demyelination patterns, and stem cell source were stratified.

RESULTS

Of the 36 boys who underwent hematopoietic stem cell transplantation, the median (range) age was 7.2 (4.2-15.4) years; 18 were presymptomatic and 18 were symptomatic. Twenty-seven patients (75%) were alive at a median (interquartile range [IQR]) follow-up of 108 (40-157) months. Sixteen of 18 presymptomatic patients (89%) survived, and 13 (72%) had an event-free survival with a median (IQR) survival time of 49 (37-115) months. Among the symptomatic patients, 11 of 18 (61%) survived, but only 1 was an event-free survival (6%) (median [IQR] time, 9 [3-22] months). Of the 9 patients who received a bone marrow transplant from a matched family donor, all survived. Among the 36 patients, 6 disease-related deaths (17%) and 3 transplant-related deaths (8%) occurred. Deaths from disease progression (n = 6) occurred only in patients with demyelination patterns other than parieto-occipital. In total, 18 patients (50%) displayed limited parieto-occipital (Loes score <9) or frontal (Loes score <4) demyelination before transplant (favorable). None of these patients died of progressive disease or developed major functional disabilities, 15 of them were characterized by stable neuroimaging after the transplant, and event-free survival was 77% (95% CI, 60%-100%). In contrast, the other 18 patients with more extended parieto-occipital demyelination (n = 6), frontal involvement (n = 4), or other demyelination patterns (n = 8) progressed (unfavorable): 13 patients developed epilepsy and 10 developed major functional disabilities, and their event-free survival was 0%. This newly defined neuroimaging assessment correlated best with neurocognitive deterioration after transplant (hazard ratio, 16.7; 95% CI, 4.7-59.6).

CONCLUSIONS AND RELEVANCE

All patients with favorable neuroimaging who received matched bone marrow remained stable after transplant, while some of the other patients developed major functional disabilities. Newborn screening for the disease and regular neuroimaging are recommended, and patients who lack a matched bone marrow donor may need to find new therapeutic options.

Modeling and rescue of defective blood-brain barrier function of induced brain microvascular endothelial cells from childhood cerebral adrenoleukodystrophy patients

Background

X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene. 40% of X-ALD patients will convert to the deadly childhood cerebral form (ccALD) characterized by increased permeability of the brain endothelium that constitutes the blood–brain barrier (BBB). Mutation information and molecular markers investigated to date are not predictive of conversion. Prior reports have focused on toxic metabolic byproducts and reactive oxygen species as instigators of cerebral inflammation and subsequent immune cell invasion leading to BBB breakdown. This study focuses on the BBB itself and evaluates differences in brain endothelium integrity using cells from ccALD patients and wild-type (WT) controls.

Methods

The blood–brain barrier of ccALD patients and WT controls was modeled using directed differentiation of induced pluripotent stem cells (iPSCs) into induced brain microvascular endothelial cells (iBMECs). Immunocytochemistry and PCR confirmed characteristic expression of brain microvascular endothelial cell (BMEC) markers. Barrier properties of iBMECs were measured via trans-endothelial electrical resistance (TEER), sodium fluorescein permeability, and frayed junction analysis. Electron microscopy and RNA-seq were used to further characterize disease-specific differences. Oil-Red-O staining was used to quantify differences in lipid accumulation. To evaluate whether treatment with block copolymers of poly(ethylene oxide) and poly(propylene oxide) (PEO–PPO) could mitigate defective properties, ccALD-iBMECs were treated with PEO–PPO block copolymers and their barrier properties and lipid accumulation levels were quantified.

Results

iBMECs from patients with ccALD had significantly decreased TEER (2592 ± 110 Ω cm²) compared to WT controls (5001 ± 172 Ω cm²). They also accumulated lipid droplets to a greater extent than WT-iBMECs. Upon treatment with a PEO–PPO diblock copolymer during the differentiation process, an increase in TEER and a reduction in lipid accumulation were observed for the polymer treated ccALD-iBMECs compared to untreated controls.

Conclusions

The finding that BBB integrity is decreased in ccALD and can be rescued with block copolymers opens the door for the discovery of BBB-specific molecular markers that can indicate the onset of ccALD and has therapeutic implications for preventing the conversion to ccALD.

Electronic supplementary material

The online version of this article (10.1186/s12987-018-0094-5) contains supplementary material, which is available to authorized users.