Neurocognitive benchmarks following transplant for emerging cerebral adrenoleukodystrophy

Characterizing visual processing deficits in cerebral adrenoleukodystrophy

BACKGROUND AND OBJECTIVES

Cerebral adrenoleukodystrophy (CALD) can cause visual impairment, but early symptoms are often missed or misdiagnosed. The framework of cerebral visual impairment (CVI) distinguishes deficits in sensory detection ("lower order") from those of perception and interpretation ("higher order"). This study describes visual deficits in patients with CALD and higher order visual function assessed with a virtual reality (VR) interface combined with eye tracking.

METHODS

A retrospective medical record review assessed the prevalence of visual deficits in patients with CALD, as well as lesion burden on brain MRI using the Loes MRI severity score. A VR-based task measured visual spatial processing performance in participants with CALD and controls.

RESULTS

Out of 89 CALD patients, 69 % had at least one sign or symptom of visual impairment. Lower order deficits were seen in 56 % of patients, and higher order deficits were seen in 59 % of patients who underwent neuropsychological testing. Even in early stage disease (Loes MRI severity score ≤ 3), visual impairment was present in more than half of patients (58 %). On prospective VR-based assessment, the CALD group (n = 30) had impaired visual search performance (lower success rate and longer reaction time) compared with controls (n = 38). In both groups, there was a trend of worsening performance with increasing task difficulty.

DISCUSSION

Higher order visual deficits, not just impairment of visual acuity, visual fields, or oculomotor function, are common in all stages of CALD. Beyond neuropsychological testing, VR-based functional testing allows for quantitative assessment of higher order visual perceptual deficits that are relevant to everyday tasks and may serve as an important marker of neurological decline.

Diffusion Tensor Imaging in Boys With Adrenoleukodystrophy: Identification of Cerebral Disease and Association With Neurocognitive Outcomes

BACKGROUND AND OBJECTIVES

Childhood cerebral adrenoleukodystrophy (C-ALD) is a severe inflammatory demyelinating disease that must be treated at an early stage to prevent permanent brain injury and neurocognitive decline. In standard clinical practice, C-ALD lesions are detected and characterized by a neuroradiologist reviewing anatomical MRI scans. We aimed to assess whether diffusion tensor imaging (DTI) is sensitive to the presence and severity of C-ALD lesions and to investigate associations with neurocognitive outcomes after hematopoietic cell therapy (HCT).

METHODS

In this retrospective cohort study, we analyzed high-resolution anatomical MRI, DTI, and neurocognitive assessments from boys with C-ALD undergoing HCT at the University of Minnesota between 2011 and 2021. Longitudinal DTI data were compared with an age-matched group of boys with ALD and no lesion (NL-ALD). DTI metrics were obtained for atlas-based regions of interest (ROIs) within 3 subdivisions of the corpus callosum (CC), corticospinal tract (CST), and total white matter (WM). Between-group baseline and slope differences in fractional anisotropy (FA) and axial (AD), radial (RD), and mean (MD) diffusivities were compared using analysis of covariance accounting for age, MRI severity (Loes score), and lesion location.

RESULTS

Among patients with NL-ALD (n = 14), stable or increasing FA, stable AD, and stable or decreasing RD and MD were generally observed during the 1-year study period across all ROIs. In comparison, patients with mild posterior lesions (Loes 1-2; n = 13) demonstrated lower baseline FA in the CC splenium (C-ALD 0.50 ± 0.08 vs NL-ALD 0.58 ± 0.04; pBH = 0.022 adjusted Benjamini-Hochberg p-value), lower baseline AD across ROIs (e.g., C-ALD 1.34 ± 0.03 ×10-9 m2/s in total WM vs NL-ALD 1.38 ± 0.04 ×10-9 m2/s; pBH = 0.005), lower baseline RD in CC body and CST, and lower baseline MD across ROIs except CC splenium. Longitudinal slopes in CC splenium showed high sensitivity and specificity in differentiating early C-ALD from NL-ALD. Among all patients with C-ALD (n = 38), baseline Loes scores and DTI metrics were associated with post-HCT neurocognitive functions, including processing speed (e.g., FA WM Spearman correlation coefficient R = 0.64) and visual-motor integration (e.g., FA WM R = 0.71).

DISCUSSION

DTI was sensitive to lesion presence and severity as well as clinical neurocognitive effects of C-ALD. DTI metrics quantify C-ALD even at an early stage.

Neurocognitive outcomes in pediatric hematological cancer survivors post-HSCT: A systematic review

BACKGROUND

Pediatric hematological cancer survivors who undergo hematopoietic stem cell transplantation (HSCT) may experience long-term neurocognitive impairments. This systematic review aims to assess the neurocognitive outcomes in pediatric hematological cancer survivors at least 5 years post-HSCT.

METHODOLOGY

A comprehensive search was conducted in multiple databases, including PubMed, ScienceDirect, Cochrane Library, and ClinicalTrials.gov, until October 2022. Relevant studies assessing the neurocognitive affect after 5 years of HSCT were identified and included in the review. The quality of included studies was assessed using the ROBINS-I tool to evaluate the risk of bias.

RESULTS

A total of five studies met the inclusion criteria and were included in the review. The studies consistently demonstrated adverse effects of HSCT on neurocognitive outcomes in pediatric hematological cancer survivors after 5 years of the treatment. The most prominent impact was observed on global cognitive outcomes, including intelligence, attention, memory, and executive functioning. Specific cognitive domains, such as processing speed and academic achievement, were also significantly affected. Several studies reported a relationship between HSCT-related factors (e.g., age at transplantation, radiation therapy, graft-versus-host disease) and neurocognitive impairments.

CONCLUSION

This systematic review provides evidence of the adverse impact of HSCT on neurocognitive outcomes in pediatric hematological cancer survivors at least 5 years post-transplantation. The findings highlight the importance of long-term monitoring and intervention strategies to mitigate these neurocognitive sequelae. Future research should focus on identifying risk factors and developing targeted interventions to optimize the neurocognitive functioning of this vulnerable population. Healthcare professionals involved in the care of pediatric hematological cancer survivors should be aware of these potential long-term neurocognitive effects and incorporate appropriate assessments and interventions into survivorship care plans.

Neurocognitive and mental health impact of adrenoleukodystrophy across the lifespan: Insights for the era of newborn screening

X-linked adrenoleukodystrophy (ALD) is a rare inherited neurological disorder that poses considerable challenges for clinical management throughout the lifespan. Although males are generally more severely affected than females, the time course and presentation of clinical symptoms are otherwise difficult to predict. Opportunities to improve outcomes for individuals with ALD are rapidly expanding due to the introduction of newborn screening programs for this condition and an evolving treatment landscape. The aim of this comprehensive review is to synthesize current knowledge regarding the neurocognitive and mental health effects of ALD. This review provides investigators and clinicians with context to improve case conceptualization, inform prognostic counseling, and optimize neuropsychological and mental health care for patients and their families. Results highlight key predictive factors and brain-behavior relationships associated with the diverse manifestations of ALD. The review also discusses considerations for endpoints within clinical trials and identifies gaps to address in future research.

Identification of a Novel Non-Canonical Splice-Site Variant in ABCD1

Cerebral adrenoleukodystrophy (CALD) is a fatal genetic disease characterized by rapid, devastating neurological decline, with a narrow curative treatment window in the early stage. Non-canonical splice-site (NCSS) variants can easily be missed during genomic DNA analyses, and only a few of them in ABCD1 have been explored. Here, we studied a Chinese patient with clinical features similar to those of early-stage CALD but with a negative molecular diagnosis and a sibling who had presumably died of CALD. Trio-based whole-exome sequencing (trio-WES) and RNA sequencing (RNA-Seq) revealed a novel hemizygote NCSS variant c.901-25_901-9 del in ABCD1 intron 1, resulting in a complex splicing pattern. The in vitro minigene assay revealed that the c.901-25_901-9 del construct contained two aberrant transcripts that caused skipping of exon 2 and a small 48-bp deletion on left of the same exon. We identified a novel NCSS variant, that extends the spectrum of the known ABCD1 variants, and demonstrated the pathogenicity of this gene variant. Our findings highlight the importance of combining RNA-Seq and WES techniques for prompt diagnosis of leukodystrophy with NCSS variants.

Presymptomatic Lesion in Childhood Cerebral Adrenoleukodystrophy: Timing and Treatment

BACKGROUND AND OBJECTIVES

We sought to characterize the natural history and standard-of-care practices between the radiologic appearance of brain lesions, the appearance of lesional enhancement, and treatment with hematopoietic stem-cell transplant or gene therapy among boys diagnosed with presymptomatic childhood-onset cerebral adrenoleukodystrophy (CCALD).

METHODS

We analyzed a multicenter, mixed retrospective/prospective cohort of patients diagnosed with presymptomatic CCALD (Neurologic Function Score = 0, Loes Score [LS] = 0.5-9.0, and age <13 years). Two time-to-event survival analyses were conducted: (1) time from CCALD lesion onset-to-lesional enhancement and (2) time from enhancement-to-treatment. The analysis was repeated in the subset of patients with (1) the earliest evidence of CCALD, defined as an MRI LS ≤ 1, and (2) patients diagnosed between 2016 and 2021.

RESULTS

Seventy-one boys were diagnosed with presymptomatic cerebral lesions at a median age of 6.4 years [2.4-12.1] with a LS of 1.5 [0.5-9.0]. Fifty percent of patients had lesional enhancement at diagnosis. In the remaining 50%, the median Kaplan-Meier (KM)-estimate of time from diagnosis-to-lesional enhancement was 6.0 months (95% CI 3.6-17.8). The median KM-estimate of time from enhancement-to-treatment is 3.8 months (95% CI 2.8-5.9); 2 patients (4.2%) developed symptoms before treatment. Patients with a diagnostic LS ≤ 1 were younger (5.8 years [2.4-11.5]), had a time-to-enhancement of 4.7 months (95% CI 2.7-9.30), and were treated in 3.8 months (95% CI 3.1-7.1); no patients developed symptoms before treatment. Time from CCALD diagnosis-to-treatment decreased over the course of the study (ρ = -0.401, p = 0.003).

DISCUSSION

Our findings offer a more refined understanding of the timing of lesion formation, enhancement, and treatment among boys with presymptomatic CCALD. These data offer benchmarks for standardizing clinical care and designing future clinical trials.

Variables affecting outcomes after allogeneic hematopoietic stem cell transplant for cerebral adrenoleukodystrophy

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in early cerebral adrenoleukodystrophy can stabilize neurologic function and improve survival but has associated risks including transplant-related mortality (TRM), graft failure, and graft-versus-host disease (GVHD). An observational study of 59 patients with median age at allo-HSCT of 8 years addressed impact of donor source, donor match, conditioning regimen, and cerebral disease stage on first allo-HSCT outcomes. Efficacy analyses included 53 patients stratified by disease category: advanced disease (AD; n = 16) with Loes score >9 or neurological function score (NFS) >1 and 2 early disease (ED) cohorts (ED1 [Loes ≤4 and NFS ≤1; n = 24] and ED2 [Loes >4-9 and NFS ≤1; n = 13]). Survival free of major functional disabilities and without second allo-HSCT at 4 years was significantly higher in the ED (66%) vs AD (41%) cohort (P = .015) and comparable between ED1 and ED2 cohorts (P = .991). The stabilization of neurologic function posttransplant was greater in the ED vs AD cohort, with a median change from baseline at 24 months after allo-HSCT in NFS and Loes score, respectively, of 0 and 0.5 in ED1 (n = 13), 0.5 and 0 in ED2 (n = 6), and 2.5 and 3.0 (n = 4) in AD cohort. TRM was lower in the ED (7%) compared with the AD (22%) cohort; however, the difference was not significant (P = .094). Transplant-related safety outcomes were also affected by transplant-related characteristics: graft failure incidence was significantly higher with unrelated umbilical cord grafts vs matched related donors (P = .039), and acute GVHD and graft failure incidences varied by conditioning regimen. This study was registered at www://clinicaltrials.gov as #NCT02204904.

Structure and Function of the ABCD1 Variant Database: 20 Years, 940 Pathogenic Variants, and 3400 Cases of Adrenoleukodystrophy

The progressive neurometabolic disorder X-linked adrenoleukodystrophy (ALD) is caused by pathogenic variants in the ABCD1 gene, which encodes the peroxisomal ATP-binding transporter for very-long-chain fatty acids. The clinical spectrum of ALD includes adrenal insufficiency, myelopathy, and/or leukodystrophy. A complicating factor in disease management is the absence of a genotype–phenotype correlation in ALD. Since 1999, most ABCD1 (likely) pathogenic and benign variants have been reported in the ABCD1 Variant Database. In 2017, following the expansion of ALD newborn screening, the database was rebuilt. To add an additional level of confidence with respect to pathogenicity, for each variant, it now also reports the number of cases identified and, where available, experimental data supporting the pathogenicity of the variant. The website also provides information on a number of ALD-related topics in several languages. Here, we provide an updated analysis of the known variants in ABCD1. The order of pathogenic variant frequency, overall clustering of disease-causing variants in exons 1–2 (transmembrane domain spanning region) and 6–9 (ATP-binding domain), and the most commonly reported pathogenic variant p.Gln472Argfs*83 in exon 5 are consistent with the initial reports of the mutation database. Novel insights include nonrandom clustering of high-density missense variant hotspots within exons 1, 2, 6, 8, and 9. Perhaps more importantly, we illustrate the importance of collaboration and utility of the database as a scientific, clinical, and ALD-community-wide resource.

Differential outcomes for frontal versus posterior demyelination in childhood cerebral adrenoleukodystrophy

In the most common variant of childhood cerebral adrenoleukodystrophy (cALD), demyelinating brain lesions are distributed predominately in parieto-occipital white matter. Less frequently, lesions first develop in frontal white matter. This matched cohort study examined whether outcomes after standard treatment with hematopoietic cell transplantation (HCT) differ in patients with early stage frontal lesions as compared to parieto-occipital lesions. Retrospective chart review identified seven pediatric patients with frontal cALD lesions and MRI severity score < 10 who underwent a single HCT at our center between 1990 and 2019. Concurrent MRI, neurocognitive and psychiatric outcomes at last comprehensive follow-up (mean 1.2 years; range 0.5-2.1 years) were compared with a group of seven boys with the parieto-occipital variant matched on pre-HCT MRI severity score. Both groups showed similar rates of transplant complications and radiographic disease advancement. Neurocognitive outcomes were broadly similar, with more frequent working memory deficits among individuals with frontal lesions. Psychiatric problems (hyperactivity, aggression, and atypical behavior) were considerably more common and severe among patients with frontal lesions. Aligned with the critical role of the frontal lobes in emotional and behavioral regulation, functional disruption of self-regulation skills is widely observed among patients with frontal lesions. Comprehensive care for cALD should address needs for psychiatric care and management.

A Longitudinal Analysis of Early Lesion Growth in Presymptomatic Patients with Cerebral Adrenoleukodystrophy

BACKGROUND AND PURPOSE

Cerebral adrenoleukodystrophy is a devastating neurological disorder caused by mutations in the ABCD1 gene. Our aim was to model and compare the growth of early cerebral lesions from longitudinal MRIs obtained in presymptomatic patients with progressive and arrested cerebral adrenoleukodystrophy using quantitative MR imaging-based lesion volumetry.

MATERIALS AND METHODS

We retrospectively quantified and modeled the longitudinal growth of early cerebral lesions from 174 MRIs obtained from 36 presymptomatic male patients with cerebral adrenoleukodystrophy. Lesions were manually segmented using subject-specific lesion-intensity thresholding. Volumes were calculated and plotted across time. Lesion velocity and acceleration were calculated between sequentially paired and triplet MRIs, respectively. Linear mixed-effects models were used to assess differences in growth parameters between progressive and arrested phenotypes.

RESULTS

The median patient age was 7.4 years (range, 3.9-37.0 years). Early-stage cerebral disease progression was inversely correlated with age (ρ = -0.6631, P < .001), early lesions can grow while appearing radiographically stable, lesions undergo sustained acceleration in progressive cerebral adrenoleukodystrophy (β = 0.10 mL/month2 [95% CI, 0.05-0.14 mL/month2], P < .001), and growth trajectories diverge between phenotypes in the presymptomatic time period.

CONCLUSIONS

Measuring the volumetric changes in newly developing cerebral lesions across time can distinguish cerebral adrenoleukodystrophy phenotypes before symptom onset. When factored into the overall clinical presentation of a patient with a new brain lesion, quantitative MR imaging-based lesion volumetry may aid in the accurate prediction of patients eligible for therapy.

Very long chain acylcarnitines and lysophosphatidylcholines in screening of peroxisomal disease in children by tandem mass spectrometry

To investigate the value of very long chain acylcarnitine (VLCAC) and lysophosphatidylcholine (LPC) in screening of peroxisomal disease in children. Eighteen children with peroxisomal disease, including 14 cases of X-linked adrenoleukodystrophy (X-ALD group) and 4 cases of Zellweger syndrome (ZS group) diagnosed based on clinical symptoms, MRI and genetic tests were enrolled in the study; and 200 healthy children were selected as control group. Samples of dried blood spots were collected from all subjects, VLCAC and LPC in dried blood spots were extracted by solvent containing internal isotopic standards hexacosanoylcarnitine (H-C26) and C26:0 lysophosphatidylcholine (H-C26:0-LPC). The eicosanoylcarnitine (C20), docosanoylcarnitine (C22), tetracosanoylcarnitine (C24), hexacosanoylcarnitine (C26), C20:0 lysophosphatidylcholine (C20:0-LPC), C22:0 lysophosphatidylcholine (C22:0-LPC), C24:0 lysophosphatidylcholine (C24:0-LPC) and C26:0 lysophosphatidylcholine (C26:0-LPC) were detected by tandem mass spectrometry (MS/MS). The above 8 indicators and the ratios were compared among the groups using Kruskal-Wallis test and Mann-Whitney test; the contribution of each index to the disease were analyzed by partial least square method. Except C24:0-LPC/C20:0-LPC, there were significant differences in all indicators and ratios among all groups (<0.05 or <0.01). There were differences in most indicators and ratios between X-ALD group and the control group, as well as between ZS group and the control group, but there was no difference between the X-ALD group and the ZS group. PLS-DA analysis showed that the peroxisome disease group (including X-ALD group and ZS group) and the control group were able to be completely separated, and C26 had the highest variable importance for the projection (VIP) value. MS/MS detection of VLCAC and LPC can be used as a screening method for peroxisomal disease, and C26 may be a sensitive indicator for diagnosis.

MRI surveillance of boys with X-linked adrenoleukodystrophy identified by newborn screening: Meta-analysis and consensus guidelines

BACKGROUND

Among boys with X-Linked adrenoleukodystrophy, a subset will develop childhood cerebral adrenoleukodystrophy (CCALD). CCALD is typically lethal without hematopoietic stem cell transplant before or soon after symptom onset. We sought to establish evidence-based guidelines detailing the neuroimaging surveillance of boys with neurologically asymptomatic adrenoleukodystrophy.

METHODS

To establish the most frequent age and diagnostic neuroimaging modality for CCALD, we completed a meta-analysis of relevant studies published between January 1, 1970 and September 10, 2019. We used the consensus development conference method to incorporate the resulting data into guidelines to inform the timing and techniques for neuroimaging surveillance. Final guideline agreement was defined as >80% consensus.

RESULTS

One hundred twenty-three studies met inclusion criteria yielding 1285 patients. The overall mean age of CCALD diagnosis is 7.91 years old. The median age of CCALD diagnosis calculated from individual patient data is 7.0 years old (IQR: 6.0-9.5, n = 349). Ninety percent of patients were diagnosed between 3 and 12. Conventional MRI was most frequently reported, comprised most often of T2-weighted and contrast-enhanced T1-weighted MRI. The expert panel achieved 95.7% consensus on the following surveillance parameters: (a) Obtain an MRI between 12 and 18 months old. (b) Obtain a second MRI 1 year after baseline. (c) Between 3 and 12 years old, obtain a contrast-enhanced MRI every 6 months. (d) After 12 years, obtain an annual MRI.

CONCLUSION

Boys with adrenoleukodystrophy identified early in life should be monitored with serial brain MRIs during the period of highest risk for conversion to CCALD.