Adrenoleukodystrophy Research Articles

A pilot study of newborn screening for X-linked adrenoleukodystrophy based on liquid chromatography-tandem mass spectrometry method for detection of C26:0- lysophosphatidylcholine in dried blood spots: results from 43,653 newborns in a southern Chinese population

BackgroundX-linked adrenoleukodystrophy (X-ALD) is a rare X-linked disease caused by mutations of the ABCD1 gene. C26:0-lysophosphatidylcholine (C26:0-LPC) has been proved to be an accurate biomarker for X-ALD. This study aims to propose an effective method for screening of X-ALD and to evaluate the performance of the newborn screening (NBS) assay for X-ALD in Guangzhou. MethodsC26:0-LPC in dried blood spots (DBS) was extracted by methanol solution containing isotope-labelled internal standard (C26:0-d4-LPC) and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The sensitivity of the method was assessed in eight male X-ALD patients, two female carriers and 583 healthy controls. The method was conducted on 43,653 newborns. Next generation sequencing was performed on screen-positive samples. Plasma analysis of very long-chain fatty acids and genetic counselling were performed by way of follow-up. ResultsElevated C26:0-LPC were 100% sensitive for screening of X-ALD. Of 43,653 newborns, 32 (18 males, 14 females) screened positive. Of these, 14 (43.7%) were identified ABCD1 variants, including seven hemizygous males and seven heterozygous females, and two (6.3%) were diagnosed with other peroxisomal disorders. ConclusionThe LC-MS/MS method for screening of X-ALD can identify males, heterozygous females and other peroxisomal disorders. The incidence of X-ALD in Guangzhou is not low.

Generation and characterization of induced pluripotent stem cell lines derived from skin fibroblasts of patients with adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a rare peroxisome disease with phenotypic heterogeneity. There is a lack of suitable in vitro models to study its pathogenesis. We established two strains of iPSCs from skin fibroblasts of patients with childhood cerebral ALD and Addison’s disease, respectively. CytoTune™2.0 Sendai reprogramming kit was used. The iPSC lines showed typical stem cell morphology, normal karyotype, and carrying ABCD1 variation. The iPSC lines express pluripotency markers, and have the capacity to differentiate into three germ layers. iPSCs can be used as an alternative cell source for ALD in vitro model to study its pathogenesis and therapeutic strategies.

Diagnosing X-Linked Adrenoleukodystrophy after Implementation of Newborn Screening: A Reference Laboratory Perspective.

Adrenoleukodystrophy (ALD) is caused by pathogenic variants in the ABCD1 gene, encoding for the adrenoleukodystrophy protein (ALDP), leading to defective peroxisomal β-oxidation of very long-chain and branched-chain fatty acids (VLCFA). ALD manifests in both sexes with a spectrum of phenotypes, but approximately 35% of affected males develop childhood cerebral adrenoleukodystrophy (CCALD), which is lethal without hematopoietic stem cell transplant performed before symptoms start. Hence, ALD was added to the Recommended Uniform Screening Panel after the successful implementation in New York State (2013-2016). To date, thirty-five states have implemented newborn screening (NBS) for ALD, and a few programs have reported on the successes and challenges experienced. However, the overall impact of NBS on early detection of ALD has yet to be fully determined. Here, we conducted a retrospective analysis of VLCFA testing performed by our reference laboratory (ARUP Laboratories, Salt Lake City, UT, USA) over 10 years. Rate of detection, age at diagnosis, and male-to-female ratio were evaluated in patients with abnormal results before and after NBS implementation. After NBS inclusion, a significant increase in abnormal results was observed (471/6930, 6.8% vs. 384/11,670, 3.3%; p < 0.0001). Patients with ALDP deficiency identified via NBS were significantly younger (median age: 30 days vs. 21 years; p < 0.0001), and males and females were equally represented. ALD inclusion in NBS programs has increased pre-symptomatic detection of this disease, which is critical in preventing adrenal crisis as well as the severe cerebral form.

Gene therapy for neurodegenerative disorders in children: dreams and realities

Gene therapy encompasses the administration of biological medicinal products containing recombinant nucleic acids, mainly DNA, with the aim of treating or curing diseases. This represents a unique therapeutic strategy to reach the brain, in order to prevent or halt a neurodegenerative process. During the past decade, active multidisciplinary research has started to solve many issues for gene therapy in neurodegenerative disorders in terms of vectors, modes of administration, and expression of the therapeutic DNA. The engineering of hematopoietic stem cells (HSC) with lentivirus vectors for ex vivo gene therapy has demonstrated efficiency in reaching the brain through their transformation into microglial/macrophages cells with a long-term gene expression of the therapeutic vector as an alternative to autologous HSC transplants. Two drugs based on this strategy have been approved to date. The first is for metachromatic leukodystrophy (MLD), a severe lysosomal storage disease, and provides high levels of the deficient enzyme; the second one is for cerebral forms of X-linked adrenoleukodystrophy (X-ALD), and works by halting the neuroinflammation process. However, due to the long-lasting effect of the procedure, the therapy is applicable only to pre- or pauci/oligo-symptomatic patients. In vivo gene therapy via direct injection into the brain or the cerebrospinal fluid, but also by intravenous injection, represents a more efficient approach; however, many challenges remain to be solved despite the approval of two drugs: one for the early infantile form of spinal muscular atrophy (SMA), in which the gene product injected intravenously is able to prevent spinal motoneuron neurodegeneration. The second one, for aromatic L-amino acid decarboxylase (AADC) deficiency, provides the defective enzyme to the basal ganglia via intraparenchymal injection. The production of vectors able to reach the brain target cells with a sufficiently high expression remains a major bottleneck. In parallel, efforts must continue in order to better define (i) the natural history and clinical outcomes of many neurodegenerative disorders with childhood onset, and (ii) the mechanisms involved in the neurodegenerative process. © 2023 Published by Elsevier Masson SAS on behalf of French Society of Pediatrics.

Adrenoleukodystrophy/Adrenomyeloneuropathy and Neurogenic Bladder Dysfunction. A Review

One of the conditions associated with adrenoleukodystrophy (ALD) / adrenomyeloneuropathy (AMN) is neurogenic lower urinary tract dysfunction (LUTD). A thorough examination of patients with ALD/AMN in most cases can reveal overactive bladder (OAB), which often remains undiagnosed because its clinical manifestations are underestimated against the background of numerous neurologic symptoms. In addition, in some cases, urologic symptomatology is the first sign of ALD/AMN that prompts the urologist to consider further evaluation of the patient. In this case, the urologist can play a significant role in the patient’s life, as timely diagnosis and treatment of ALD/AMN improve disease outcomes and reduce the likelihood of complications of ALD/AMN-associated conditions. To date, there are few studies devoted to the understanding of LUTD in ALD/AMN. In this article, we reviewed the current literature on OAB in patients with ALD/AMN.

Gene and Cellular Therapies for Leukodystrophies.

Leukodystrophies are a heterogenous group of inherited, degenerative encephalopathies, that if left untreated, are often lethal at an early age. Although some of the leukodystrophies can be treated with allogeneic hematopoietic stem cell transplantation, not all patients have suitable donors, and new treatment strategies, such as gene therapy, are rapidly being developed. Recent developments in the field of gene therapy for severe combined immune deficiencies, Leber's amaurosis, epidermolysis bullosa, Duchenne's muscular dystrophy and spinal muscular atrophy, have paved the way for the treatment of leukodystrophies, revealing some of the pitfalls, but overall showing promising results. Gene therapy offers the possibility for overexpression of secretable enzymes that can be released and through uptake, allow cross-correction of affected cells. Here, we discuss some of the leukodystrophies that have demonstrated strong potential for gene therapy interventions, such as X-linked adrenoleukodystrophy (X-ALD), and metachromatic leukodystrophy (MLD), which have reached clinical application. We further discuss the advantages and disadvantages of ex vivo lentiviral hematopoietic stem cell gene therapy, an approach for targeting microglia-like cells or rendering cross-correction. In addition, we summarize ongoing developments in the field of in vivo administration of recombinant adeno-associated viral (rAAV) vectors, which can be used for direct targeting of affected cells, and other recently developed molecular technologies that may be applicable to treating leukodystrophies in the future.

The experiences of parents of children diagnosed with cerebral adrenoleukodystrophy.

Adrenoleukodystrophy (ALD) is a rare X-linked neurodegenerative disease, affecting the brain, spinal cord and adrenal cortex. Childhood cerebral ALD (CCALD) is the most severe form of disease, involving rapidly progressive neurological deterioration. The treatment option for CCALD is allogenic haemopoietic stem cell transplant, which is only successful for early-stage disease. Parents' experiences of CCALD can inform healthcare delivery. To detail the experiences of parents of children diagnosed with cerebral ALD. A descriptive qualitative study. Parents were recruited via a UK-based community support organisation. Data collection involved single semi-structured interviews structured around a topic guide and conducted remotely. Data were analysed using the thematic analysis approach. Twelve parents from 11 families with a total of 16 children with ALD contributed to the study. Their 16 children with ALD followed one of three disease pathways, determined by the extent of neurological damage at diagnosis. Three themes, and their respective sub themes, describe the pathways and what they meant for parents. 'No possibility of treatment' concerns situations when CCALD was diagnosed at an advanced stage, the landslide of deterioration parents witnessed and their efforts to maintain normality. 'Close to the treatment threshold' describes situations where a small treatment window required parents to make agonising treatment decisions. 'Watching and waiting' explains the challenges for parents when disease was detected early enabling children to benefit from timely treatment. Parents' experiences were largely defined by the extent of cerebral damage at diagnosis, which determined the availability and success of treatment. There were specific challenges related to the three situations, indicating areas where support from health and care services may help parents deal with this devastating diagnosis. This study indicates support needs of parents across the spectrum of CCALD diagnoses and highlights the critical importance of early diagnosis.

FRI433 Hypogonadism In Males With Adrenoleukodystrophy

Abstract Disclosure: J. Ramirez Alcantara: None. N. Grant: None. T.L. Stanley: Research Investigator; Self; Pfizer, Inc. F. Eichler: Consulting Fee; Self; consultant to Alnylam, Autobahn, Ionis, Minoryx, Orchard, Origen, Poxel, Takeda Therapeutics,and Taysha Gene Therapies, is a consultant to Third Rock Ventures on rare neurological disorders. Grant Recipient; Self; GLIA-CTN from National Institute of Neurological Disorders and Stroke (NINDS). Owner/Co-Owner; Self; founder of SwanBio Therapeutics. Research Investigator; Self; primary investigator (PI) of ex vivo lentiviral gene therapy trial in cerebral adrenoleukodystrophy sponsored by bluebird bio, the site-PI of Minoryx trial of leriglitazone for adrenomyeloneuropathy. N.A. Tritos: None. X-linked adrenoleukodystrophy (ALD) is a rare peroxisomal disorder caused by mutations in the ABCD1 gene. Little is known about the prevalence and characteristics of hypogonadism in ALD.We conducted a retrospective chart review to investigate hypogonadism in adult males with ALD. The presence of hypogonadism was determined by a clinician’s diagnosis and/or a total testosterone (TT) level below 249 ng/dL. Prospectively, we distributed a survey and evaluated serum gonadotropins and TT levels. The survey included the quantitative Saint Louis University Androgen Deficiency in the Aging Male (qADAM) questionnaire, a standardized screening tool for hypogonadism (score range: 10-50, lower scores indicate more symptoms). The normal laboratory ranges were 249-836 ng/dL (TT), 1-12 IU/L (FSH), and 2-12 IU/L (LH).We included 56 patients in the study (median age 36.2 years, range 19.3-72.4 years). Forty-seven (84%) patients had signs of myelopathy and 46 (82%) had adrenal insufficiency. Puberty data were available for 11 (20%) patients; two had documentation of delayed puberty onset, one of whom required testosterone treatment at age 15 years to jumpstart puberty. Thirty-one (55%) patients had erectile dysfunction and 24 (43%) used phosphodiesterase-5 inhibitors. Three patients had low libido and two had anorgasmia. Fifteen (27%) patients, two of whom required fertility treatment, had children. Nine (16%) patients had hypogonadism (median [IQR] age of diagnosis 37.4 [35.7,39.0] years), six of whom were on testosterone replacement. The median [IQR] TT level was 200 [143,240] ng/dL at the time of hypogonadism diagnosis. In patients with normal TT, the median [IQR] TT level was 498 [445,615] ng/dL. Twenty-two patients had LH levels and 18 had FSH levels available from clinical testing. In patients with hypogonadism, the median [IQR] levels for LH and FSH were 8.2 [7.2,8.4] and 8.3 [7.4,8.3] IU/L respectively. In patients with normal TT, the levels were 7.6 [5.7,10.4] and 4.0 [3.0,5.3] IU/L. There were no differences in LH or FSH levels between patients with normal TT and hypogonadism. Eight patients completed the prospective survey (median age 38.1 years). The median age of reported puberty onset was 13 years (range 12-15). Four patients, one of whom required fertility treatment, had children. Two (25%) patients reported low libido and 3 (38%) reported ED. The mean qADAM score was 36.5 (SD 5). We obtained prospective laboratory evaluation in ten patients. Median [IQR] levels were 564 [504,663] ng/dL (TT), 6.9 [5.4,9.8] IU/L (FSH), and 11 [7.2,13.8] IU/L (LH). In contrast to the retrospective clinical cohort, no patients had laboratory evidence of hypogonadism. Our results suggest that males with ALD may be at higher risk of developing central hypogonadism. In addition, ED and low libido may be present in males with ALD without laboratory evidence of hypogonadism. Presentation: Friday, June 16, 2023

SAT281 Screening For Adrenocortical Insufficiency In Patients With X-linked Adrenoleukodystrophy

Abstract Disclosure: J. Berquist: None. R.N. Kiani: None. M.P. Wahl: None. Background: A 41-year-old male initially presented to neurology clinic for complaints of poor balance, lower extremity weakness, and numbness. He previously had exam findings of lower extremity spasticity and hyperreflexia, distal vibratory loss, positive Romberg, and difficulty with Tandem gait. His symptoms had been progressive following an ankle sprain 8 years earlier and he was treated with physical therapy and baclofen. He is highly active otherwise and enjoys rock climbing, which was difficult to do given his symptoms. Clinical Case: Genetic screening was performed to evaluate for hereditary spastic paraparesis, which resulted positive for a mutation in the ABCD1 gene with a p.Lys336Glu mutation of uncertain significance. Interestingly, this ABDC1 variant was not detected in submitted maternal sample, hence patient’s mutation likely occurred de novo. This variant is not established in population databases (gnomAD no frequency) but has been observed in at least one individual with clinical features of adrenomyeloneuropathy. X-linked adrenoleukodystrophy causes impairment of beta oxidation that leads to accumulation of saturated very long chain fatty acids (VFLA) in multiple tissues. There are many clinical phenotypes, but they are hallmarked by neurologic signs and symptoms. Although neurologic symptoms can often develop in childhood, they can be delayed and present in adulthood, as can adrenal insufficiency (AI). However, males are overwhelmingly likely to develop adrenocortical insufficiency compared to females. Our patient presented with a BMI of 22.94, HR 50 bpm, and blood pressure 120/76; reflecting his active lifestyle. Recent electrolytes were within normal limits, AM cortisol was 13.0, and ACTH 544.0 Given the elevated ACTH and known cause of adrenal insufficiency, we proceeded with ACTH stimulation test. Peak cortisol resulted at 13.1 (at 60 minutes) and he was started on replacement glucocorticoid therapy per body-surface area. Upon further literature review, patients can also develop loss of mineralocorticoid production. Renin and aldosterone were ordered and were both within normal limits. Conclusion: Males with adrenoleukodystrophy are at a much higher risk of developing adrenal insufficiency (AI) compared to females. Additionally, AI will often develop later in life, so a low threshold for screening should be present for the endocrinologist. Mineralocorticoid deficiency can also develop, although not as commonly. Loss of adrenal function can lead to patient demise, and therefore adrenal function needs to be closely evaluated in people with leukodystrophy. Presentation: Saturday, June 17, 2023

SAT315 A Case Of PAI "Do Not Miss This Rare Cause"

Abstract Disclosure: R. Alshantti: None. C. Musurakis: None. U. Rafat: None. W. Akhter: None. J.L. Gilden: None. A. Moid: None. Background: Adrenoleukodystrophy (ALD) is an X-linked disorder caused by a mutation in the ABCD1 gene, located at Xq28. This impairs beta-oxidation and breakdown of very long chain fatty acids (VLCFAs) which then accumulate in the CNS, adrenal cortex, and Leydig cells of the testes, leading to three main phenotypes of X-ALD: childhood cerebral ALD, adrenomyeloneuropathy AMN, and adrenal insufficiency (AI). AI presents in 47% of X-ALD cases by age 10 years. X-ALD represents a spectrum of phenotypes that vary in age of onset, severity, and clinical characteristic. AI may predate, occur simultaneously with, or follow the onset of the neurologic deterioration. While in the majority, it is inherited in an X-linked manner, at least 4.1% of individuals with X-ALD have a de novo pathogenic variant of ABCD1. Case Description: A 30-year-old male, previously healthy, was found to have adrenal nodule on CT renal during the evaluation of a transient episode of acute abdominal pain. Further evaluation of the adrenal nodule with a CT adrenal protocol showed a 1.5 cm x 1.0 cm right adrenal nodule, HU 22, washout of 66.7% consistent with an adrenal adenoma. Evaluation of adrenal hormones failed to show abnormal hypersecretion, but rather suggested insufficiency. Lab tests: RENIN FRZ PLS 45.76 ng/mL/h (0.25 - 5.82), ALDOSTERONE &amp;lt;1 ng/dL, ACTH &amp;gt;1250 pg/mL (0 - 47), SALIV CORT 0.06 mcg/dL, DHEAS 28.19 ug/dL (34.5 - 568.9). The patient was referred to endocrinology. Only reported symptom was poor exercise tolerance. Diagnosis of primary adrenal insufficiency was confirmed by low AM cortisol of 7.91 ug/dL, and very high ACTH of &amp;gt;1250 H pg/mL. He was started on glucocorticoid &amp; mineralocorticoid replacements. An evaluation to determine the etiology of PAI was conducted. The patient was not taking any medications or drugs. Family history was noncontributory. 21 OH Ab was negative. Quantiferron was negative. Our patient had no risk factors or clinical manifestations to suggest TB or fungal infections. No bleeding disorders. CT adrenal findings did not suggest infiltrative, infectious, hemorrhage, or malignant etiologies. Blood tests for VLCFAs showed elevations in phytanic, C22:0, C24:0, C26:0, C24/C22, &amp; C26/C22. These are consistent with X-linked adrenomyeloneuropathy. Genetic testing has confirmed the diagnosis; POSITIVE for a hemizygous pathogenic variant in ABCD1, consistent with a diagnosis of X-linked adrenoleukodystrophy/adrenomyeloneuropathy (ALD/AMN). Conclusion: Our case highlights the importance of a comprehensive evaluation to determine the cause of PAI. When autoimmunity and infectious etiologies are ruled out in male patients, it is crucial to consider X- ALD regardless of age at presentation, family history, or presence/absence of neurologic symptoms. This diagnosis is particularly important not to miss, since X-ALD can have devastating implications not only for the patient but also the family. Presentation: Saturday, June 17, 2023

Biomarker-based risk prediction for the onset of neuroinflammation in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is highly variable, ranging from slowly progressive adrenomyeloneuropathy to severe brain demyelination and inflammation (cerebral ALD, CALD) affecting males with childhood peak onset. Risk models integrating blood-based biomarkers to indicate CALD onset, enabling timely interventions, are lacking. Therefore, we evaluated the prognostic value of blood biomarkers in addition to current neuroimaging predictors for early detection of CALD. We measured blood biomarkers in a retrospective, male CALD risk-assessment cohort consisting of 134 X-ALD patients and 66 controls and in a phenotype-blinded validation set (25 X-ALD boys, 4-13 years) using Simoa®and Luminex® technologies. Among 25 biomarkers indicating axonal damage, astrocye/microglia activation, or immune-cell recruitment, neurofilament light chain (NfL) had the highest prognostic value for early indication of childhood/adolescent CALD. A plasma NfL cut-off level of 8.33pg/mL, determined in the assessment cohort, correctly discriminated CALD with an accuracy of 96% [95% CI: 80-100] in the validation group. Multivariable logistic regression models revealed that combining NfL with GFAP or cytokines/chemokines (IL-15, IL-12p40, CXCL8, CCL11, CCL22, and IL-4) that were significantly elevated in CALD vs healthy controls had no additional benefit for detecting neuroinflammation. Some cytokines/chemokines were elevated only in childhood/adolescent CALD and already upregulated in asymptomatic X-ALD children (IL-15, IL-12p40, and CCL7). In adults, NfL levels distinguished CALD but were lower than in childhood/adolescent CALD patients with similar (MRI) lesion severity. Blood GFAP did not differentiate CALD from non-inflammatory X-ALD. Biomarker-based risk prediction with a plasma NfL cut-off value of 8.33pg/mL, determined by ROC analysis, indicates CALD onset with high sensitivity and specificity in childhood X-ALD patients. A specific pro-inflammatory cytokine/chemokine profile in asymptomatic X-ALD boys may indicate a primed, immanent inflammatory state aligning with peak onset of CALD. Age-related differences in biomarker levels in adult vs childhood CALD patients warrants caution in predicting onset and progression of CALD in adults. Further evaluations are needed to assess clinical utility of the NfL cut-off for risk prognosis of CALD onset. Austrian Science Fund, European Leukodystrophy Association.

Attitudes of Patients with Adrenoleukodystrophy towards Sex-Specific Newborn Screening.

Newborn screening (NBS) for X-linked adrenoleukodystrophy (ALD) can identify affected individuals before the onset of life-threatening manifestations. Some countries have decided to only screen boys (sex-specific screening). This study investigates the attitudes of individuals with ALD towards sex-specific NBS for ALD. A questionnaire was sent to all patients in the Dutch ALD cohort. Invitees were asked who they thought should be screened for ALD: only boys, both boys and girls or neither. The motives and background characteristics of respondents were compared between screening preferences. Out of 108 invitees, 66 participants (61%), 38 men and 28 women, participated in this study. The majority (n = 53, 80%) favored screening both newborn boys and girls for ALD, while 20% preferred boys only. None of the respondents felt that newborns should not be screened for ALD. There were no differences in the background characteristics of the respondents between screening preferences. Our study revealed a diverse range of motivations underlying respondents' screening preferences. This study is one of the first to investigate the attitudes of patients towards sex-specific screening for ALD. The outcomes of this study can offer insights to stakeholders engaged in the implementation of NBS programs. ALD patients are important stakeholders who can provide valuable input in this process.

System-based integrated metabolomics and microRNA analysis identifies potential molecular alterations in human X-linked cerebral adrenoleukodystrophy brain.

X-linked adrenoleukodystrophy is a severe demyelinating neurodegenerative disease mainly affecting males. The severe cerebral adrenoleukodystrophy (cALD) phenotype has a poor prognosis and underlying mechanism of onset and progression of neuropathology remains poorly understood. In this study we aim to integrate metabolomic and microRNA (miRNA) datasets to identify variances associated with cALD. Postmortem brain tissue samples from five healthy controls (CTL) and five cALD patients were utilized in this study. White matter from ALD patients was obtained from normal-appearing areas, away from lesions (NLA) and from the periphery of lesions- plaque shadow (PLS). Metabolomics was performed by gas chromatography coupled with time-of-flight mass spectrometry and miRNA expression analysis was performed by next generation sequencing (RNAseq). Principal component analysis revealed that among the three sample groups (CTL, NLA and PLS) there were 19 miRNA, including several novel miRNA, of which 17 were increased with disease severity and 2 were decreased. Untargeted metabolomics revealed 13 metabolites with disease severity-related patterns with 7 increased and 6 decreased with disease severity. Ingenuity pathway analysis of differentially altered metabolites and miRNA comparing CTL with NLA and NLA with PLS, identified several hubs of metabolite and signaling molecules and their upstream regulation by miRNA. The transomic approach to map the crosstalk between miRNA and metabolomics suggests involvement of specific molecular and metabolic pathways in cALD and offers opportunity to understand the complex underlying mechanism of disease severity in cALD.

ABCD1 Transporter Deficiency Results in Altered Cholesterol Homeostasis.

X-linked adrenoleukodystrophy (X-ALD), the most common peroxisomal disorder, is caused by mutations in the peroxisomal transporter ABCD1, resulting in the accumulation of very long-chain fatty acids (VLCFA). Strongly affected cell types, such as oligodendrocytes, adrenocortical cells and macrophages, exhibit high cholesterol turnover. Here, we investigated how ABCD1 deficiency affects cholesterol metabolism in human X-ALD patient-derived fibroblasts and CNS tissues of Abcd1-deficient mice. Lipidome analyses revealed increased levels of cholesterol esters (CE), containing both saturated VLCFA and mono/polyunsaturated (V)LCFA. The elevated CE(26:0) and CE(26:1) levels remained unchanged in LXR agonist-treated Abcd1 KO mice despite reduced total C26:0. Under high-cholesterol loading, gene expression of SOAT1, converting cholesterol to CE and lipid droplet formation were increased in human X-ALD fibroblasts versus healthy control fibroblasts. However, the expression of NCEH1, catalysing CE hydrolysis and the cholesterol transporter ABCA1 and cholesterol efflux were also upregulated. Elevated Soat1 and Abca1 expression and lipid droplet content were confirmed in the spinal cord of X-ALD mice, where expression of the CNS cholesterol transporter Apoe was also elevated. The extent of peroxisome-lipid droplet co-localisation appeared low and was not impaired by ABCD1-deficiency in cholesterol-loaded primary fibroblasts. Finally, addressing steroidogenesis, progesterone-induced cortisol release was amplified in X-ALD fibroblasts. These results link VLCFA to cholesterol homeostasis and justify further consideration of therapeutic approaches towards reducing VLCFA and cholesterol levels in X-ALD.

Childhood cerebral adrenoleukodystrophy (CCALD) in France: epidemiology, natural history, and burden of disease - A population-based study

BackgroundX-linked adrenoleukodystrophy (ALD) is a rare metabolic and neurodegenerative disorder belonging to the group of leukodystrophies, with an estimated incidence around 1:25 000 newborns worldwide, mostly among men. Childhood Cerebral ALD (CCALD) is the most severe form with a poor prognosis if not properly treated during the first years of life. Currently, only allogeneic hematopoietic stem cell transplantation (allo-HSCT) is widely available for CCALD treatment. To date, there is a lack of data regarding CCALD epidemiology, natural history, and current management in France. This knowledge is crucial for the development of new therapies such as gene therapies. In this context, the French National Health Data System (SNDS) is a particularly indicated database to collect information meeting these needs. A non-interventional, national, real-life, retrospective study was performed using secondary data from the national ALD registry (LEUKOFRANCE) and SNDS. CCALD patients detected between 2009 and 2018 and successfully matched between LEUKOFRANCE and SNDS were included in this study. Index date was defined as the first CCALD event detected during study period. Subgroups of patients with sufficient follow-up (6 months) and history (1 year) available around index date were analyzed to assess CCALD burden and natural history.Results52 patients were included into the matched cohort. Median annual incidence of CCALD was estimated at 4 patients. Median age at CCALD diagnosis was 7.0 years. Among patients without allo-HSCT, five-year overall survival was 66.6%, with 93.3% of them presenting at least one CCALD symptom and 62.1% presenting a least one major functional disability (MFD). Among patients with allo-HSCT, five-year overall survival was 94.4%, with only 11.1% of patients presenting CCALD symptoms, and 16.7% of presenting a MFD. Mean annualized costs were almost twice as important among patients without allo-HSCT, with 49,211€, 23,117€, respectively. Costs were almost exclusively represented by hospitalizations.ConclusionsTo the best of our knowledge, this is the most up to date study analyzing CCALD epidemiology, clinical and economic burden in France. The necessity of a precocious management with HSCT highlight the potential benefits of including an expanded screening program among newborns, coupled with family screenings when a mutation is detected.

Dicarboxylic acylcarnitine biomarkers in peroxisome biogenesis disorders

The peroxisome is an essential eukaryotic organelle with diverse metabolic functions. Inherited peroxisomal disorders are associated with a wide spectrum of clinical outcomes and are broadly divided into two classes, those impacting peroxisome biogenesis (PBD) and those impacting specific peroxisomal factors. Prior studies have indicated a role for acylcarnitine testing in the diagnosis of some peroxisomal diseases through the detection of long chain dicarboxylic acylcarnitine abnormalities (C16-DC and C18-DC). However, there remains limited independent corroboration of these initial findings and acylcarnitine testing for peroxisomal diseases has not been widely adopted in clinical laboratories. To explore the utility of acylcarnitine testing in the diagnosis of peroxisomal disorders we applied a LC-MS/MS acylcarnitine method to study a heterogenous clinical sample set (n = 598) that included residual plasma specimens from nineteen patients with PBD caused by PEX1 or PEX6 deficiency, ranging in severity from lethal neonatal onset to mild late onset forms. Multiple dicarboxylic acylcarnitines were significantly elevated in PBD patients including medium to long chain (C8-DC to C18-DC) species as well as previously undescribed elevations of malonylcarnitine (C3-DC) and very long chain dicarboxylic acylcarnitines (C20-DC and C22-DC). The best performing plasma acylcarnitine biomarkers, C20-DC and C22-DC, were detected at elevated levels in 100% and 68% of PBD patients but were rarely elevated in patients that did not have a PBD. We extended our analysis to residual newborn screening blood spot cards and were able to detect dicarboxylic acylcarnitine abnormalities in a newborn with a PBD caused by PEX6 deficiency. Similar to prior studies, we failed to detect substantial dicarboxylic acylcarnitine abnormalities in blood spot cards from patients with x-linked adrenoleukodystrophy (x-ald) indicating that these biomarkers may have utility in quickly narrowing the differential diagnosis in patients with a positive newborn screen for x-ald. Overall, our study identifies widespread dicarboxylic acylcarnitine abnormalities in patients with PBD and highlights key acylcarnitine biomarkers for the detection of this class of inherited metabolic disease.

VUS: Variant of uncertain significance or very unclear situation?

The advancements in population screening, including newborn screening, enables the identification of disease-causing variants and timely initiation of treatment. However, screening may also identify mild variants, non-disease variants, and variants of uncertain significance (VUS). The identification of a VUS poses a challenge in terms of diagnostic uncertainty and confusion. X-linked adrenoleukodystrophy (ALD) serves as an illustrative example of this complex issue. ALD is a monogenic neurometabolic disease with a complex clinical presentation and a lack of predictive tests for clinical severity. Despite the success of ALD newborn screening, a significant proportion (62%) of missense variants identified through newborn screening exhibit uncertainty regarding their pathogenicity. Resolving this issue requires ongoing efforts to accurately classify variants and refine screening protocols. While it is undisputable that ALD newborn screening greatly benefits boys with the disease, the identification of VUS underscores the need for continuous research and collaboration in improving screening practices.

Abcd1 deficiency accelerates cuprizone-induced oligodendrocyte loss and axonopathy in a demyelinating mouse model of X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD), the most frequent, inherited peroxisomal disease, is caused by mutations in the ABCD1 gene encoding a peroxisomal lipid transporter importing very long-chain fatty acids (VLCFAs) from the cytosol into peroxisomes for degradation via β-oxidation. ABCD1 deficiency results in accumulation of VLCFAs in tissues and body fluids of X-ALD patients with a wide range of phenotypic manifestations. The most severe variant, cerebral X-ALD (CALD) is characterized by progressive inflammation, loss of the myelin-producing oligodendrocytes and demyelination of the cerebral white matter. Whether the oligodendrocyte loss and demyelination in CALD are caused by a primary cell autonomous defect or injury to oligodendrocytes or by a secondary effect of the inflammatory reaction remains unresolved. To address the role of X-ALD oligodendrocytes in demyelinating pathophysiology, we combined the Abcd1 deficient X-ALD mouse model, in which VLCFAs accumulate without spontaneous demyelination, with the cuprizone model of toxic demyelination. In mice, the copper chelator cuprizone induces reproducible demyelination in the corpus callosum, followed by remyelination upon cuprizone removal. By immunohistochemical analyses of oligodendrocytes, myelin, axonal damage and microglia activation during de-and remyelination, we found that the mature oligodendrocytes of Abcd1 KO mice are more susceptible to cuprizone-induced cell death compared to WT mice in the early demyelinating phase. Furthermore, this effect was mirrored by a greater extent of acute axonal damage during demyelination in the KO mice. Abcd1 deficiency did not affect the function of microglia in either phase of the treatment. Also, the proliferation and differentiation of oligodendrocyte precursor cells and remyelination progressed at similar rates in both genotypes. Taken together, our findings point to an effect of Abcd1 deficiency on mature oligodendrocytes and the oligodendrocyte-axon unit, leading to increased vulnerability in the context of a demyelinating insult.

X-Linked Adrenoleukodystrophy in an 11 Years Old Child: A Case Report

An 11-year-old boy was referred to the pediatric ward for regression in school performance and behavioral problems. The clinic has been evolving for two years. Given the clinical deterioration, the patient is treated at the pediatrician. A somatic assessment is performed and highlights lesions of the white matter evoking the diagnosis of X-linked adrenoleukodystrophy (X-ALD), confirmed by the metabolic assessment. No curative treatment will be proposed given the stage of the disease; the patient dies less than two years later. The X-ALD is a degenerative disease of the white matter having a prevalence estimated at 1/20.000 cases worldwide. The mutated gene, located on the long arm of chromosome X, encodes a peroxisomal membrane protein. Over 500 mutations are known and cause a disorder of fatty acids b-oxidation. Several phenotypes exist without phenotype-genotype relationship. The diagnosis of X-ALD is mainly based on brain magnetic resonance and blood very long chain fatty acids (VLCFA) blood level. Allogenic hematopoietic stem cell transplanta-tion, only known cure can be achieved in patients with asymptomatic (from screening) or early stage. Without treatment, the survival prognosis at diagnosis is an average of 3 years. Genetic counseling and screenings (pre-natal, neo-natal and family) are essentials to improve this diagnosis.

Exploratory study of autophagy inducer sirolimus for childhood cerebral adrenoleukodystrophy.

X-linked adrenoleukodystrophy (ALD) is a peroxisomal disease caused by mutations in the ABCD1 gene. Childhood cerebral ALD (CCALD) is characterized by inflammatory demyelination, rapidly progressing, often fatal. Hematopoietic stem cell transplant only delays disease progression in patients with early-stage cerebral ALD. Based on emergency humanitarianism, this study aims to investigate the safety and efficacy of sirolimus in the treatment of patients with CCALD. This was a prospective, single-center, one-arm clinical trial. We enrolled patients with CCALD, and all enrolled patients received sirolimus treatment for three months. Adverse events were monitored and recorded to evaluate the safety. The efficacy was evaluated using the neurologic function scale (NFS), Loes score, and white matter hyperintensities. A total of 12 patients were included and all presented with CCALD. Four patients dropped out and a total of eight patients in the advanced stage completed a 3-month follow-up. There were no serious adverse events, and the common adverse events were hypertonia and oral ulcers. After sirolimus treatment, three of the four patients with an initial NFS > 10 showed improvements in their clinical symptoms. Loes scores decreased by 0.5-1 point in two of eight patients and remained unchanged in one patient. Analysis of white matter hyperintensities revealed a significant decrease in signal intensity (n = 7, p = 0.0156). Our study suggested that autophagy inducer sirolimus is safe for CCALD. Sirolimus did not improve clinical symptoms of patients with advanced CCALD significantly. Further study with larger sample size and longer follow-up is needed to confirm the drug efficacy.Clinical Trial registration: https://www.chictr.org.cn/historyversionpuben.aspx, identifier ChiCTR1900021288.