BACKGROUND: Metachromatic Leukodystrophy (MLD) is a rare, autosomal recessive lysosomal storage disease characterised by the progressive loss of motor function and severe decline in cognitive function. Limited information is available on the burden MLD places on patients and their families and the medical and social support these patients need. Three UK-based MLD patient organisations commissioned an online survey, and follow-up semi-structured interviews to describe and quantify these burdens across MLD subtypes, stage of disease (including end of life) and treatment status (untreated, gene therapy or hematopoietic stem cell transplant [HSCT]).
RESULTS: A total of 24 patients were included in the study: thirteen late infantile (LI), six early juvenile (EJ), two late juvenile (LJ) and three adult onset (AO). Six patients had received gene therapy and one had received an HSCT. MLD patients receiving no disease modifying treatment bore a high symptom burden: 94% were wheelchair dependent, 88% required tube feeding, 88% were incontinent, 82% had lost their speech and all the children were either unable to attend education or needed specialist provision. Patients were reliant on numerous medical interventions and assistive equipment. All early-onset patients (LI and EJ) were wheelchair dependent, and tube fed, with all EJ patients having lost all speech. The caregiving responsibilities of parents impacted their employment, finances, relationships and health. Patients treated with gene therapy or HSCT were more mobile and were able to eat normally and two thirds of the children were able to attend mainstream school.
CONCLUSIONS: The impact of illness that patients and their caregivers faced was extensive, and the level of care, amount of medication, number of hospital visits and educational support required were substantial. Financial constraints often brought about by inability to work also placed considerable strain on families. The study increases understanding of the burden of MLD on patients and their families, and the level of unmet need in the treatment of the disease.

This review is an effort towards the development of substrate reduction therapy using cerebroside sulfotransferase (CST) as a target protein for the development of inhibitors intended to treat pathophysiological condition resulting from the accumulation of sulfatide, a product from the catalytic action of CST. Accumulation of sulfatides leads to progressive impairment and destruction of the myelin structure, disruption of normal physiological transmission of electrical impulse between nerve cells, axonal loss in the central and peripheral nervous system and cumulatively gives a clinical manifestation of metachromatic leukodystrophy. Thus, there is a need to develop specific and potent CST inhibitors to positively control sulfatide accumulation. Structural similarity and computational studies revealed that LYS85, SER172 and HIS141 are key catalytic residues that determine the catalytic action of CST through the transfer of sulfuryl group from the donor PAPS to the acceptor galactosylceramide. Computational studies revealed catalytic site of CST consists two binding site pocket including PAPS binding pocket and substrate binding pocket. Specific substrate site residues in CST can be targeted to develop specific CST inhibitors. This review also explores the challenges of CST-directed substrate reduction therapy as well as the opportunities available in natural products for inhibitor development.

This abstract provides an overview of metachromatic leukodystrophy (MLD), an autosomal recessive disorder stemming from arylsulfatase A deficiency. MLD leads to cerebroside sulfate accumulation, causing central and peripheral demyelination. Clinical manifestations vary by age group: late-infantile (rapid progression), juvenile (slower progression), and adult-onset (psychiatric symptoms). A case study details a 23-year-old with progressive vision impairment, motor weakness, and cognitive changes. Examination and MRI findings led to suspicion of MLD, later confirmed by enzyme testing. Optic nerve involvement is emphasized, along with diagnostic criteria involving enzyme assays, imaging, and urinary sulfatide excretion tests. While no cure exists, symptomatic and supportive care, including hematopoietic stem cell transplantation, remains key in MLD management.

To understand the benefit-risk profile for historical and current treatments for MLD.
A systematic review was conducted on the effectiveness, safety, and costs of MLD treatments: allogeneic haematopoietic stem cell transplantation (HSCT) and atidarsagene autotemcel (arsa-cel) according to best practice.
A total of 6940 titles and abstracts were retrieved from the literature searches and 26 from other sources. From these, 35 manuscripts reporting on a total of 12 studies were selected for inclusion in the review. There were no controlled multi-armed trials. However, we provide observations comparing two interventional therapies (alloHSCT and arsa-cel) and each of these to standard/supportive care (natural history). There were no benefits for survival, gross motor function and cognitive function for LI patients receiving alloHSCT, as patients experienced disease progression similar to LI natural history. For juvenile patients receiving alloHSCT, no differences in survival were observed versus natural history, however stabilisation of cognitive and motor function were reported for some patients (particularly for pre- or minimally-symptomatic LJ patients), while others experienced disease progression. Furthermore, alloHSCT was associated with severe complications such as treatment-related mortality, graft versus host disease, and re-transplantation in both LI and EJ treated patients. Most LI and EJ patients treated with arsa-cel appeared to have normal development, preservation, or slower progression of gross motor function and cognitive function, in contrast to the rapid decline observed in natural history patients. A survival benefit for arsa-cel versus natural history and versus alloHSCT was observed in LI patients.LI and EJ patients treated with arsa-cel had better gross motor function and cognitive function compared to alloHSCT, which had limited effect on motor and cognitive decline. No data has been reported for arsa-cel treatment of LJ patients.
Overall, this systematic review indicates that compared to NHx and HSCT, treatment with arsa-cel results in clinically relevant benefits in LI and EJ MLD patients by preserving cognitive function and motor development in most patients, and increased survival for LI patients. Nevertheless, further research is required to confirm these findings, given they are based on results from non-RCT studies.

Metachromatic leukodystrophy is a neurological lysosomal deposit disease that affects public health despite its low incidence in the population. Currently, few reports are available on pathophysiological events related to enzyme deficiencies and subsequent sulfatide accumulation. This research aims to examine the use of metformin as an alternative treatment to counteract these effects. This was evaluated in human Schwann cells (HSCs) transfected or non-transfected with CRISPR-Cas9, and later treated with sulfatides and metformin. This resulted in transfected HSCs showing a significant increase in cell reactive oxygen species (ROS) production when exposed to 100 µM sulfatides (p = 0.0007), compared to non-transfected HSCs. Sulfatides at concentrations of 10 to 100 µM affected mitochondrial bioenergetics in transfected HSCs. Moreover, these analyses showed that transfected cells showed a decrease in basal and maximal respiration rates after exposure to 100 µM sulfatide. However, maximal and normal mitochondrial respiratory capacity decreased in cells treated with both sulfatide and metformin. This study has provided valuable insights into bioenergetic and mitochondrial effects of sulfatides in HSCs for the first time. Treatment with metformin (500 µM) restored the metabolic activity of these cells and decreased ROS production.

Metachromatic leukodystrophy, a fatal pediatric neurodegenerative lysosomal storage disease caused by mutations in the arylsulfatase A (ARSA) gene, is characterized by intracellular accumulation of sulfatides in the lysosomes of cells of the central nervous system (CNS). In previous studies, we have demonstrated efficacy of AAVrh.10hARSA, an adeno-associated virus (AAV) serotype rh.10 vector coding for the human ARSA gene to the CNS of a mouse model of the disease, and that catheter-based intraparenchymal administration of AAVrh.10hARSA to the CNS of nonhuman primates (NHPs) white matter results in widespread expression of ARSA. As a formal dose-escalating safety/toxicology study, we assessed the safety of intraparenchymal delivery of AAVrh.10hARSA vector to 12 sites in the white matter of the CNS of NHPs at 2.85 × 1010 (total low dose, 2.4 × 109 genome copies [gc]/site) and 1.5 × 1012 (total high dose, 1.3 × 1011 gc/site) gc, compared to AAVrh.10Null (1.5 × 1012 gc total, 1.3 × 1011 gc/site) as a vector control, and phosphate buffered saline for a sham surgical control. No significant adverse effects were observed in animals treated with low dose AAVrh.10hARSA. However, animals treated with the high dose AAVrh.10ARSA and the high dose Null vector had highly localized CNS abnormalities on magnetic resonance imaging scans at the sites of catheter infusions, and histopathology demonstrated that these sites were associated with infiltrates of T cells, B cells, microglial cells, and/or macrophages. Although these findings had no clinical consequences, these safety data contribute to understanding the dose limits for CNS white matter direct intraparenchymal administration of AAVrh.10 vectors for treatment of CNS disorders.

Metachromatic leukodystrophy (MLD) is a neurodegenerative disorder characterized by progressive demyelination due to deficiency of the enzyme arylsulfatase A (ARSA) in leukocytes, and consequently leads to impaired degradation and accumulation of cerebroside-3-sulfate (sulfatide). This study aimed to sequence the ARSA gene in a total of 43 patients with metachromatic leukodystrophy descendant from 40 Egyptian families. In addition, four carrier parents from two families with children who had died from MLD came to the clinic for genetic analysis. Prenatal diagnosis was performed for four families with molecularly diagnosed MLD sibs. Different mutations were characterized in our cohort, including missense, nonsense, splice, and deletion. Overall, 21 different mutations in the ARSA gene were detected, with 12 novel mutations, i.e. p.Arg60Pro, p.Tyr65*, p.Val112Asp, p.Arg116*, p.Gly124Asp, p.Pro193Ser, p.Gln238*, p.Gln456*, p.Thr276Lys, and p.Gly311Arg, in addition to two new acceptor splice-site mutations 685-1G > A and c.954_956 delCTT. The amniotic fluid samples revealed two carrier fetuses with heterozygous monoallelic mutations, and two affected fetuses had the homozygous biallelic mutations. In conclusion, the current study sheds light on the underlying ARSA gene defect, with an expansion of the mutation spectrum. To our knowledge, this is the first molecular study of MLD among the Egyptian population.

Metachromatic leukodystrophy (MLD) is a rare genetic disease characterised by a dysfunction of the enzyme arylsulphatase A leading to the lysosomal accumulation of cerebroside sulphate (sulphatide) causing subsequent demyelination in patients. The enzyme galactosylceramide (cerebroside) sulphotransferase (CST) catalyses the transfer of a sulphate group from 3\'-phosphoadenosine-5\'-phosphosulphate (PAPS) to cerebrosides producing sulphatides. Substrate reduction therapy for arylsulphatase A by inhibition of CST was proposed as a promising therapeutic approach. To identify competitive CST inhibitors, we synthesised and investigated analogues of the substrate galactosylceramide with variations at the anomeric position, the acyl substituent and the carbohydrate moiety, and investigated their structure-activity relationships. While most of the compounds behaved as substrates, α-galactosylceramide 16 was identified as the first competitive CST inhibitor. Compound 16 can serve as a new lead structure for the development of drugs for the treatment of this devastating disease, MLD, for which small molecule therapeutics are currently not available.

Metachromatic leukodystrophy(MLD) is an autosomal recessive hereditary neurodegenerative lysosomal storage disorder caused by the mutations in arylsulfatase A gene (ARSA), which results in the deficiency of ARSA enzyme. The common clinical characteristics of MLD are abnormal gait, and then gradually appears ataxia, spastic quadriplegia, optic atrophy, cortical blindness, and dementia. We describe two patients in China who were diagnosed with MLD and find that the four ARSA gene mutations (c.1115G>A, c.302G>T, c.893 G> T, and c.302G>T) are associated with MLD, in which c.893 G>T and c.302G>T are novel mutations by gene sequence and clinical manifestations, to further understand the relationship between MLD and ARSA gene.

Metachromatic leukodystrophy (MLD) disorder is a rare lysosomal storage disorder that leads to severe neurological symptoms and an early death. MLD occurs due to the deficiency of enzyme arylsulfatase A (ARSA) in leukocytes, and patients with MLD excrete sulfatide in their urine. In this study, the ARSA gene in 12 non-consanguineous MLD patients and 40 healthy individuals was examined using polymerase chain reaction sequencing. Furthermore, the structural and functional effects of new mutations on ARSA were analyzed using SIFT (sorting intolerant from tolerant), I-Mutant 2, and PolyPhen bioinformatics software. Here, 4 new pathogenic homozygous mutations c.585G>T, c.661T>A, c.849C>G, and c.911A>G were detected. The consequence of this study has extended the genotypic spectrum of MLD patients, paving way to a more effective method for carrier detection and genetic counseling.