Experiences of patients with metachromatic leukodystrophy, adrenoleukodystrophy, or Krabbe disease and the experiences of their family members: a qualitative systematic review.

OBJECTIVE: This review aimed to synthesize the experiences of patients with metachromatic leukodystrophy, adrenoleukodystrophy, or Krabbe disease and the experiences of their families. INTRODUCTION: Leukodystrophies are metabolic diseases caused by genetic mutations. There are multiple forms of the disease, varying in age of onset and symptoms. The progression of leukodystrophies worsens central nervous system symptoms and significantly affects the lives of patients and their families. INCLUSION CRITERIA: Qualitative studies on the experiences of patients with leukodystrophies and their family members were included. These experiences included treatments such as enzyme replacement therapy and hematopoietic stem cell transplantation; effects of tracheostomy and gastrostomy; burdens on the family, coordinating care within the health care system, and family planning due to genetic disorders. This review considered studies in any setting. METHODS: MEDLINE (Ovid), CINAHL Plus (EBSCOhost), APA PsycINFO (EBSCOhost), Scopus, and MedNar databases were searched on November 18, 2022. Study selection, critical appraisal, data extraction, and data synthesis were conducted in accordance with the JBI methodology for systematic reviews of qualitative evidence, and synthesized findings were evaluated according to the ConQual approach. RESULTS: Eleven studies were eligible for synthesis, and 45 findings were extracted corresponding with participants' voices. Of these findings, 40 were unequivocal and 5 were credible. The diseases in the included studies were metachromatic leukodystrophy and adrenoleukodystrophy; no studies were identified for patients with Krabbe disease and their families. These findings were grouped into 11 categories and integrated into 3 synthesized findings, including i) providing care by family members and health care providers as physical symptoms progress, which relates to the effects of the characteristics of progressive leukodystrophies; ii) building medical teamwork to provide appropriate support services, comprising categories related to the challenges experienced with the health care system for patients with leukodystrophy and their families; and iii) coordinating family functions to accept and cope with the disease, which included categories related to family psychological difficulties and role divisions within the family. According to the ConQual criteria, the second synthesized finding had a low confidence level, and the first and third synthesized findings had a very low confidence level. CONCLUSIONS: The synthesized findings of this review provide evidence on the experiences of patients with metachromatic leukodystrophy or adrenoleukodystrophy and their families. These findings indicate that there are challenges in managing a patient's physical condition and coordinating the health care system and family functions. REVIEW REGISTRATION: PROSPERO CRD42022318805. SUPPLEMENTAL DIGITAL CONTENT: A Japanese-language version of the abstract of this review is available [ http://links.lww.com/SRX/A49 ].

Fingolimod Rescues Demyelination in a Mouse Model of Krabbe's Disease.

Krabbe's disease is an infantile neurodegenerative disease, which is affected by mutations in the lysosomal enzyme galactocerebrosidase, leading to the accumulation of its metabolite psychosine. We have shown previously that the S1P receptor agonist fingolimod (FTY720) attenuates psychosine-induced glial cell death and demyelination both in vitro and ex vivo models. These data, together with a lack of therapies for Krabbe's disease, prompted the current preclinical study examining the effects of fingolimod in twitcher mice, a murine model of Krabbe's disease. Twitcher mice, both male and female, carrying a natural mutation in the galc gene were given fingolimod via drinking water (1 mg/kg/d). The direct impact of fingolimod administration was assessed via histochemical and biochemical analysis using markers of myelin, astrocytes, microglia, neurons, globoid cells, and immune cells. The effects of fingolimod on twitching behavior and life span were also demonstrated. Our results show that treatment of twitcher mice with fingolimod significantly rescued myelin levels compared with vehicle-treated animals and also regulated astrocyte and microglial reactivity. Furthermore, nonphosphorylated neurofilament levels were decreased, indicating neuroprotective and neurorestorative processes. These protective effects of fingolimod on twitcher mice brain pathology was reflected by an increased life span of fingolimod-treated twitcher mice. These in vivo findings corroborate initial in vitro studies and highlight the potential use of S1P receptors as drug targets for treatment of Krabbe's disease.SIGNIFICANCE STATEMENT This study demonstrates that the administration of the therapy known as fingolimod in a mouse model of Krabbe's disease (namely, the twitcher mouse model) significantly rescues myelin levels. Further, the drug fingolimod also regulates the reactivity of glial cells, astrocytes and microglia, in this mouse model. These protective effects of fingolimod result in an increased life span of twitcher mice.

Developmental outcomes of cord blood transplantation for Krabbe disease: A 15-year study.

OBJECTIVE: To describe long-term outcomes of children with early-infantile Krabbe disease who underwent hematopoietic stem cell transplantation (HSCT) in the first 7 weeks of life. METHODS: In this prospective longitudinal study, evaluations performed at baseline and follow-up included brain imaging, neurodiagnostic tests, and neurobehavioral evaluations. RESULTS: Of the 18 patients in this study (11 girls, 7 boys; mean follow-up 9.5 years, range 4-15), 5 died (3 of peritransplant complications, 1 of a surgical complication unrelated to Krabbe disease, 1 of disease progression). One of the surviving patients has normal cognitive function and 10 continue to develop cognitive skills at a slightly slower rate than normal. All surviving patients continue to gain receptive language skills, with 7 falling within the normal range. Ten patients receive speech therapy, and 2 of these patients require augmentative communication devices. Gross motor development varies widely, but 3 patients can walk independently, and 7 walk with assistive devices. Spasticity ranges from mild to severe, and 12 patients wear orthotics. Fine motor skills are generally preserved. Brain myelination and atrophy stabilized in 8 patients, improved in 4 patients, and worsened in 1 patient. Nerve conduction velocities initially improved but continue to be abnormal in most patients. CONCLUSIONS: The surviving patients function at a much higher level than untreated children or symptomatic children who underwent HSCT. These results show that early HSCT changes the natural history of this disease by improving both lifespan and functional abilities. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for children with early-infantile Krabbe disease, early HSCT improves lifespan and functional abilities.

Neurodevelopmental Outcome after Hematopoietic Cell Transplantation in Inborn Errors of Metabolism: Current Considerations and Future Perspectives.

Inborn errors of metabolism (IEM) comprise an assorted group of inherited diseases, some of which are due to disordered lysosomal or peroxisomal function and some of which might be improved following hematopoietic cell transplantation (HCT). In these disorders the onset in infancy or early childhood is typically accompanied by rapid deterioration, resulting in early death in the more severe phenotypes. Timely diagnosis and immediate referral to an IEM specialist are essential steps in optimal management. Treatment recommendations are based on the diagnosis, its phenotype, rate of progression, prior extent of disease, family values, and expectations, and the risks and benefits associated with available therapies, including HCT. International collaborative efforts are of utmost importance in determining outcomes of therapy for these rare diseases, and have improved those outcomes significantly over the last decades. In this review, we will focus on the neurodevelopmental outcomes after HCT in IEM, providing an international perspective on progress, limitations, and future directions.

Midbrain morphology reflects extent of brain damage in Krabbe disease.

INTRODUCTION: To study the relationships between midbrain morphology, Loes score, gross motor function, and cognitive function in infantile Krabbe disease. METHODS: Magnetic resonance imaging (MRI) scans were evaluated by two neuroradiologists blinded to clinical status and neurodevelopmental function of children with early or late infantile Krabbe disease. A simplified qualitative 3-point scoring system based on midbrain morphology on midsagittal MRI was used. A score of 0 represented normal convex morphology of the midbrain, a score of 1 represented flattening of the midbrain, and a score of 3 represented concave morphology of the midbrain (hummingbird sign). Spearman correlations were estimated between this simplified MRI scoring system and the Loes score, gross motor score, and cognitive score. RESULTS: Forty-two MRIs of 27 subjects were reviewed. Analysis of the 42 scans showed normal midbrain morphology in 3 (7.1%) scans, midbrain flattening in 11 (26.2%) scans, and concave midbrain morphology (hummingbird sign) in 28 (66.7%) scans. Midbrain morphology scores were positively correlated with the Loes score (r = 0.81, p < 0.001) and negatively correlated with both gross motor and cognitive scores (r = -.84, p < 0.001; r = -0.87, p < 0.001, respectively). The inter-rater reliability for the midbrain morphology scale was κ = .95 (95% CI: 0.86-1.0), and the inter-rater reliability for the Loes scale was κ = .58 (95% CI: 0.42-0.73). CONCLUSIONS: Midbrain morphology scores of midsagittal MRI images correlates with cognition and gross motor function in children with Krabbe disease. This MRI scoring system represents a simple but reliable method to assess disease progression in patients with infantile Krabbe disease.

Compound Galactosylceramidase Gene (GALC) Heterozygosity in a Boy with Infantile Krabbe Disease (KD).

Krabbe disease (KD) (globoid cell leukodystrophy) is a degenerative, lysosomal storage disease, caused by a severe loss of galactocerebrosidase (GALC) enzymatic activity. The inheritance is autosomal recessive. KD affects the white matter of the central and peripheral nervous systems. We present a 3 year old boy in whom the disease had an 'infantile' or 'classic' presentation, with spasticity, irritability, and developmental delay. In addition the boy showed progressive severe motor and mental deterioration, difficulties in swallowing and decerebration. Molecular analysis revealed that the child is a compound heterozygote: p.Asp187Val (c.560A>T) and p.Ile250Thr (c.749T>C). The father was the carrier of p.Asp187Val (c.560A>T), while the mother was the carrier of the p.Ile250Thr (c.749T>C) in exon 6 of the GALC gene. The clinical course in this compound heterozygote is severe and the patient passed away at the age of 3 years. Genotype-phenotype relations are discussed in this Macedonian patient with KD.

Neuronal inclusions of α-synuclein contribute to the pathogenesis of Krabbe disease.

Demyelination is a major contributor to the general decay of neural functions in children with Krabbe disease. However, recent reports have indicated a significant involvement of neurons and axons in the neuropathology of the disease. In this study, we have investigated the nature of cellular inclusions in the Krabbe brain. Brain samples from the twitcher mouse model for Krabbe disease and from patients affected with the infantile and late-onset forms of the disease were examined for the presence of neuronal inclusions. Our experiments demonstrated the presence of cytoplasmic aggregates of thioflavin-S-reactive material in both human and murine mutant brains. Most of these inclusions were associated with neurons. A few inclusions were detected to be associated with microglia and none were associated with astrocytes or oligodendrocytes. Thioflavin-S-reactive inclusions increased in abundance, paralleling the development of neurological symptoms, and distributed throughout the twitcher brain in areas of major involvement in cognition and motor functions. Electron microscopy confirmed the presence of aggregates of stereotypic ß-sheet folded proteinaceous material. Immunochemical analyses identified the presence of aggregated forms of α-synuclein and ubiquitin, proteins involved in the formation of Lewy bodies in Parkinson's disease and other neurodegenerative conditions. In vitro assays demonstrated that psychosine, the neurotoxic sphingolipid accumulated in Krabbe disease, accelerated the fibrillization of α-synuclein. This study demonstrates the occurrence of neuronal deposits of fibrillized proteins including α-synuclein, identifying Krabbe disease as a new α-synucleinopathy.

High-throughput screening of stem cell therapy for globoid cell leukodystrophy using automated neurophenotyping of twitcher mice.

Globoid cell leukodystrophy (Krabbe's disease) is an autosomal recessive neurodegenerative disorder that results from the deficiency of galactosylceramidase, a lysosomal enzyme involved in active myelination. Due to the progressive, lethal nature of this disease and the limited treatment options available, multiple laboratories are currently exploring novel therapies using the mouse model of globoid cell leukodystrophy. In order to establish a protocol for motor function assessment of the twitcher mouse, this study tested the capability of an automated system to detect phenotypic differences across mouse genotypes and/or treatment groups. The sensitivity of this system as a screening tool for the assessment of therapeutic interventions was determined by the administration of murine bone marrow-derived stem cells into twitcher mice via intraperitoneal injection. Animal behavior was analyzed using the Noldus EthoVision XT7 software. Novel biomarkers, including abnormal locomotion (e.g., velocity, moving duration, distance traveled, turn angle) and observed behaviors (e.g., rearing activity, number of defecation boli), were established for the twitcher mouse. These parameters were monitored across all mouse groups, and the automated system detected improved locomotion in the treated twitcher mice based on the correction of angular velocity, turn angle, moving duration, and exploratory behavior, such as thigmotaxis. Further supporting these findings, the treated mice showed improved lifespan, gait, wire hang ability, twitching severity and frequency, and sciatic nerve histopathology. Taken together, these data demonstrate the utility of computer-based neurophenotyping for motor function assessment of twitcher mice and support its utility for detecting the efficacy of stem cell-based therapy for neurodegenerative disorders.

Infant with irritability, feeding problems, and progressive developmental abnormalities presenting repeatedly to a pediatric emergency department.

Emergency physicians often deal with diagnostically elusive cases that may present repeatedly over the course of illness. The infant presented here had a chronic history, prompting multiple physician contacts for initially seemingly common problems. Assessing the patient's progression of symptoms over time and eliciting a brief developmental history in the emergency department (ED) helped guide decision-making toward admission and appropriate diagnostic workup.

Neuropsychological outcomes of several storage diseases with and without bone marrow transplantation.

Neuropsychological assessment is essential in providing documentation of the untreated natural history of storage diseases associated with dementia and quantifying the effectiveness of treatment on central nervous system function. Baseline characterization and outcome of bone marrow transplantation (BMT) for three leukodystrophies and three mucopolysaccharidoses are presented. Results suggests that BMT for Hurler syndrome, adrenoleukodystrophy, and globoid cell leukodystrophy can be effective in preventing dementia if done early enough in the disease. Sanfilippo and Hunter syndromes do not benefit and BMT is not recommended. For metachromatic leukodystrophy, BMT is not recommended for symptomatic early-onset forms of the disease. Further longitudinal follow-up is needed to determine whether the benefits outweigh the risks of BMT for late-onset and preclinical metachromatic leukodystrophy.

Biochemical, genetic, psychometric, and neuropsychological studies in heterozygotes of a family with globoid cell leucodystrophy (Krabbe's disease).

Detection of a patient suffering from Krabbe's disease led to carrier screening in his family. Determination of galactosylceramide beta-galactosidase activity revealed the occurrence of two different alleles among the carriers of the same family. Heterozygotes and their noncarrier relatives were studied using psychometric and neuropsychological tests under blind conditions. It was found that compared to seven adult noncarrier relatives 19 adult carriers differ significantly in their general IQ and some subtests of the Wechsler Intelligence Scale for adults (WISA), including spatial cognition. Reaction times were significantly slower in the carriers with enzyme activity below 25% of the control values. Most of the carriers of this family have had myopia since early childhood.