Unilateral Vocal Cord Paralysis in a Patient with Anti-Galactocerebroside Antibodies: A Case Report.

Anti-galactocerebroside (Gal-C) antibodies are present in patients with conditions such as Guillain-Barré syndrome and mycoplasma pneumonia. We report a rare case of left vocal cord paralysis in a patient with anti-Gal-C IgG antibodies that improved after administeration of antivirals and steroids.

Deficiency of galactosyl-ceramidase in adult oligodendrocytes worsens disease severity during chronic experimental allergic encephalomyelitis.

Galactosyl-ceramidase (GALC) is a ubiquitous lysosomal enzyme crucial for the correct myelination of the mammalian nervous system during early postnatal development. However, the physiological consequence of GALC deficiency in the adult brain remains unknown. In this study, we found that mice with conditional ablation of GALC activity in post-myelinating oligodendrocytes were lethally sensitized when challenged with chronic experimental allergic encephalomyelitis (EAE), in contrast with the non-lethal dysmyelination observed in Galc-ablated mice without the EAE challenge. Mechanistically, we found strong inflammatory demyelination without remyelination and an impaired fusion of lysosomes and autophagosomes with accumulation of myelin debris after a transcription factor EB-dependent increase in the lysosomal autophagosome flux. These results indicate that the physiological impact of GALC deficiency is highly influenced by the cell context (oligodendroglial vs. global expression), the presence of inflammation, and the developmental time when it happens (pre-myelination vs. post-myelination). We conclude that Galc expression in adult oligodendrocytes is crucial for the maintenance of adult central myelin and to decrease vulnerability to additional demyelinating insults.

Splicing mutations of GALC in adult patient with adult-onset Krabbe disease: case report and review of literature.

Krabbe disease (KD) is classed as the lysosomal storage disease with mutations in the galactosylceramidase (GALC) gene, and commonly showed as autosomal recessive pattern with 30-kb deletion in infantile subtype. In this case, we report a 39-years adult-onset KD (AOKD) patient with multiple sclerosis-like symptoms and neuroimaging changes. She carries the heterozygous mutations in GALC included a missense mutation of c.1901T>C from her mother, and a splicing mutation of c.908+5G>A from her father. The splicing mutations in KD are reviewed and confirmed that c.908+5G>A is a novel splicing mutation in AOKD.

Clinical feature, GALC variant spectrum, and genotype-phenotype correlation in Korean Krabbe disease patients: Multicenter experience over 13 years.

Krabbe disease (KD) is an autosomal recessive neurodegenerative disorder caused by deficiency of the galactocerebrosidase (GALC) due to variants in the GALC gene. Here, we provide the first and the largest comprehensive analysis of clinical and genetic characteristics, and genotype-phenotype correlations of KD in Korean in comparison with other ethnic groups. From June 2010 to June 2023, 10 patients were diagnosed with KD through sequencing of GALC. Clinical features, and results of GALC sequencing, biochemical test, neuroimaging, and neurophysiologic test were obtained from medical records. An additional nine previously reported Korean KD patients were included for review. In Korean KD patients, the median age of onset was 2 years (3 months-34 years) and the most common phenotype was adult-onset (33%, 6/18) KD, followed by infantile KD (28%, 5/18). The most frequent variants were c.683_694delinsCTC (23%) and c.1901T>C (23%), while the 30-kb deletion was absent. Having two heterozygous pathogenic missense variants was associated with later-onset phenotype. Clinical features were similar to those of other ethnic groups. In Korean KD patients, the most common phenotype was the adult-onset type and the GALC variant spectrum was different from that of the Caucasian population. This study would further our understanding of KD.

Globoid Cell Leukodystrophy (Krabbe Disease): An Update.

Globoid cell leukodystrophy or Krabbe is a disease that affects children as well as adults who have mutations in the gene encoding the enzyme galactosylceramidase/galctocerebrosidase (GALC), resulting in the deposition of the toxic lipid D-galactosyl-beta1-1' sphingosine (GalSph or psychosine). Several therapeutic modalities were used to treat patients with Krabbe disease, including hematopoietic stem cell transplantation, enzyme replacement therapy, autophagy activators, intravenous immunoglobulin, and inhibitors of the Pyroptosis process, among many other approaches. In this article, I will briefly discuss the disease in both human and animal model, describe recent clinical observations as well as methods utilizing genetic analysis for diagnosis, and finally review recent advances in treating this rare and devastating disease.

Novel genetic variant associated with globoid cell leukodystrophy in a family of mixed breed dogs.

BACKGROUND: Globoid cell leukodystrophy (GCL) is a fatal autosomal recessive disease caused by variants in the galactosylceramidase (GALC) gene. Two dog breed-specific variants are reported. OBJECTIVES: Characterize the putatively causative GALC variant for GCL in a family of dogs and determine population allele frequency. ANIMALS: Four related mixed-breed puppies with signs of neurologic disease were evaluated. Subsequently, 33 related dogs were tested for genetic markers for parentage and the identified GALC variant. Additional GALC genotyping was performed on 278 banked samples from various breeds. METHODS: The 4 affected puppies had neurological exams and necropsies. DNA was isolated from blood samples. Variants in GALC were identified via Sanger sequencing. Parentage testing was performed using short tandem repeat markers. Prevalence of the GALC variant of interest was investigated in other breeds. RESULTS: GCL was confirmed histopathologically. A novel missense variant in GALC (NC_006590.4:g.58893972G>A) was homozygous in all affected animals (n = 4). A recessive mode of inheritance was confirmed by parentage testing as was variant linkage with the phenotype (LOD = 3.36). Among the related dogs (n = 33), 3 dogs were homozygous and 7 heterozygous. The variant allele was not detected in screening 278 dogs from 5 breeds. The novel variant is either unique to this family or has an extremely low allele frequency in the general population. CONCLUSIONS AND CLINICAL IMPORTANCE: A novel GALC variant was identified that likely explains GCL in this cohort. The identification of multiple causal variants for GCL in dogs is consistent with findings in humans.

rAAV2-Mediated Restoration of GALC in Neural Stem Cells from Krabbe Patient-Derived iPSCs.

Krabbe disease is a rare neurodegenerative fatal disease. It is caused by deficiency of the lysosomal enzyme galactocerebrosidase (GALC), which results in progressive accumulation of galactolipid substrates in myelin-forming cells. However, there is still a lack of appropriate neural models and effective approaches for Krabbe disease. We generated induced pluripotent stem cells (iPSCs) from a Krabbe patient previously. Here, Krabbe patient-derived neural stem cells (K-NSCs) were induced from these iPSCs. By using nine kinds of recombinant adeno-associated virus (rAAV) vectors to infect K-NSCs, we found that the rAAV2 vector has high transduction efficiency for K-NSCs. Most importantly, rAAV2-GALC rescued GALC enzymatic activity in K-NSCs. Our findings not only establish a novel patient NSC model for Krabbe disease, but also firstly indicate the potential of rAAV2-mediated gene therapy for this devastating disease.

A patient with early-onset globoid cell leukodystrophy / 中国神经精神疾病杂志

We retrospectively analyzed a child with early-onset globoid cell leukodystrophy(Krabbe's disease)caused by complex heterozygous variations in the GALC gene.The girl was admitted to the hospital at the age of 4 month with main complaints of"No obvious cause of milk refusal,poor mental state,drowsiness,convulsions,fever."Brain MRI showed abnormal symmetric signals changes in bilateral cerebellar hemispheres,bilateral internal capsule hind limbs and bilateral ventricles,thin corpus callosum,myelination process lags behind the level of children of the same age.High-throughput sequencing analysis identified compound heterozygous mutations in GALC gene(NM 000153.4):c.[908+1G>A];[194G>A and the two heterozygous mutations were correspondingly inherited from his father and mother,respectively.The application of high-throughput sequencing technology can diagnose Krabbe disease efficiently and accurately,which assists in clinical identification and diagnosis.

Reliable and Fast Genotyping Protocol for Galactosylceramidase (Galc) in the Twitcher (Twi) Mouse.

Twitcher (Twi) is a neurological Krabbe disease (KD, or globoid cell leukodystrophy) spontaneous mutant line in mice. The genome of the Twi mouse presents a single nucleotide polymorphism (SNP), leading to an enzymatically inactive galactosylceramidase (Galc) protein that causes KD. In this context, mouse Twi genotyping is an essential step in KD research. To date, the genotyping method used is labor-intensive and often has ambiguous results. Here, we evaluated a novel protocol for the genotype determination of Galc mutation status in Twi mice based on the allele-discrimination real-time polymerase chain reaction (PCR). Here, DNA is extracted from Twi mice (n = 20, pilot study; n = 120, verification study) and control group (n = 10, pilot study; n = 30 verification study) and assessed by allele-discrimination real-time PCR to detect SNP c.355G>A. Using the allele-discrimination PCR, all of the samples are identified correctly with the genotype GG (wild-type, WT), GA (heterozygote, HET), or AA (homozygote, HOM) using the first analysis and no animals are not genotyped. We demonstrated that this novel method can be used to distinguish KD timely, accurately, and without ambiguity in HOM, WT, and HET animals. This protocol represents a great opportunity to increase accuracy and speed in KD research.

Adult-onset Krabbe disease presenting with progressive myoclonic epilepsy and asymmetric occipital lesions: A case report.

Krabbe disease (KD), also known as globoid cell leukodystrophy, is a rare autosomal recessive condition caused by mutations in the galactocerebrosidase (GALC) gene. KD is more common in infants and young children than in adults. We reported the case of an adult-onset KD presenting with progressive myoclonic epilepsy (PME) and cortical lesions mimicking mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. The whole-exome sequencing (WES) identified a pathogenic homozygous missense mutation of the GALC gene. Parents of the patient were heterozygous for the mutation. The clinical, electrophysiological, and radiological data of the patient were retrospectively analyzed. The patient was a 24-year-old woman presenting with generalized seizures, progressive cognitive decline, psychiatric symptoms, gait ataxia, and action-induced myoclonus. The brain magnetic resonance imaging (MRI) revealed a right occipital cortical ribbon sign without any other damage. This single case expands the clinical phenotypes of adult-onset KD.

Adult-onset Krabbe disease presenting as isolated sensorimotor demyelinating polyneuropathy: A case report.

Krabbe disease is a rare autosomal recessive neurodegenerative disease, caused by mutations in the GALC gene, which encodes for the lysosomal enzyme galactocerebrosidase. Typical clinical manifestations of Krabbe include psychomotor deterioration, visual loss, seizures, and spasticity, that result from central nervous system demyelination. We report a case of a 35-year-old male with Krabbe who presented in adulthood with isolated severe, upper extremity predominant demyelinating sensorimotor polyneuropathy and did not develop other distinguishing clinical or radiological features of Krabbe until the later stages of the disease. The patient's diagnostic odyssey lasted 13 years from presentation to diagnosis, which was ultimately determined with the use of whole exome sequencing (WES) at the age of 48 years. The expanding phenotypic spectrum of adult-onset Krabbe Disease (AOKD) presents a diagnostic challenge that can lead to diagnostic delays and potentially affect treatment options. Our patient's case underscores the importance of pursuing WES in those with undiagnosed progressive neuromuscular disorders.

A neglected neurodegenerative disease: Adult-onset globoid cell leukodystrophy.

Globoid cell leukodystrophy (GLD), or Krabbe disease (KD) is a rare neurodegenerative disease, and adult-onset GLD is more even neglected by clinicians. This review provides detailed discussions of the serum enzymes, genes, clinical manifestations, neuroimaging features, and therapies of GLD, with particular emphasis on the characteristics of adult-onset GLD, in an attempt to provide clinicians with in-depth insights into this disease.

ß-Galactosylceramidase Deficiency Causes Upregulation of Long Pentraxin-3 in the Central Nervous System of Krabbe Patients and Twitcher Mice.

Globoid cell leukodystrophy (GLD), or Krabbe disease, is a neurodegenerative sphingolipidosis caused by genetic deficiency of lysosomal ß-galactosylceramidase (GALC), characterized by neuroinflammation and demyelination of the central (CNS) and peripheral nervous system. The acute phase protein long pentraxin-3 (PTX3) is a soluble pattern recognition receptor and a regulator of innate immunity. Growing evidence points to the involvement of PTX3 in neurodegeneration. However, the expression and role of PTX3 in the neurodegenerative/neuroinflammatory processes that characterize GLD remain unexplored. Here, immunohistochemical analysis of brain samples from Krabbe patients showed that macrophages and globoid cells are intensely immunoreactive for PTX3. Accordingly, Ptx3 expression increases throughout the course of the disease in the cerebrum, cerebellum, and spinal cord of GALC-deficient twitcher (Galctwi/twi) mice, an authentic animal model of GLD. This was paralleled by the upregulation of proinflammatory genes and M1-polarized macrophage/microglia markers and of the levels of PTX3 protein in CNS and plasma of twitcher animals. Crossing of Galctwi/twi mice with transgenic PTX3 overexpressing animals (hPTX3 mice) demonstrated that constitutive PTX3 overexpression reduced the severity of clinical signs and the upregulation of proinflammatory genes in the spinal cord of P35 hPTX3/Galctwi/twi mice when compared to Galctwi/twi littermates, leading to a limited increase of their life span. However, this occurred in the absence of a significant impact on the histopathological findings and on the accumulation of the neurotoxic metabolite psychosine when evaluated at this late time point of the disease. In conclusion, our results provide the first evidence that PTX3 is produced in the CNS of GALC-deficient Krabbe patients and twitcher mice. PTX3 may exert a protective role by reducing the neuroinflammatory response that occurs in the spinal cord of GALC-deficient animals.

A novel GALC gene mutation associated with adult-onset Krabbe disease: a case report.

To analyze the clinical, imaging, and genetic characteristics of a patient diagnosed with adult-onset Krabbe disease (KD). Clinical and imaging features of the patient were retrospectively reviewed. The patient, a 40-year-old female, presented adult-onset spastic paraplegia. Brain magnetic resonance imaging (MRI) showed white matter hyperintensities along bilateral optic radiations. Colorimetry of galactocerebrosidase enzyme activity showed low enzyme levels. A heterozygous missense mutation: c.1658G>A (p.G553E) and c.1901T>C (p.L634S) was identified in the GALC gene by whole exome sequencing, and was verified by Sanger sequencing. KD should be considered when patients presented adult-onset spastic paraplegia with classical MRI imaging features. Mutation c.1658G>A (p.G553E) was novel in GALC gene and broaden the mutation spectrum.

Clinical and molecular findings in 6 Turkish cases with Krabbe disease.

BACKGROUND: Krabbe disease is a rare lysosomal storage disorder with a neurodegenerative course that occurs because of the deficiency of the beta-galactocerebrosidase (GALC) enzyme activity. The genetic basis of Krabbe disease consists of biallelic mutations in the GALC gene, but the genetic spectrum in the Turkish population is poorly defined. We aimed to present a Turkish case-series with infantile-onset Krabbe disease, define the clinical and molecular findings and compare the genetic spectrum with the mutations previously reported in the literature. METHODS: Six cases, who were referred to our clinic between 2015-2019, with a definite diagnosis of infantileonset Krabbe disease were included in the study. The family history, clinical information, biochemical and radiological examinations of the patients were screened and evaluated. All encoded exons and exon-intron regions of the GALC gene were sequenced using next generation sequencing technology. Multiplex ligationdependent probe amplification analysis was used for deletion type mutations that could not be detected by sequence analysis. RESULTS: GALC gene sequence analysis revealed four known mutations including c.1394C > T (p.Thr465Ile), c.411_413delTAA (p.Lys139del), c.820G > C (p.Glu274Gln), and 30 kilobase deletion mutation among the exons 11-17 (IVS10del30kbp). Moreover, the c.1623G > A (p.Trp541Ter) variant, which was not previously reported in the literature, was detected in two cases. CONCLUSIONS: We believe that the demonstration of the genetic spectrum of infantile-onset Krabbe disease in Turkish patients will be an important contribution to the GALC mutation data in our country. More importantly, two novel variants were defined. This knowledge may enable early detection and treatment with the advent of a carrier or newborn screening tests.

Efficacy and Safety of a Krabbe Disease Gene Therapy.

Krabbe disease is a lysosomal storage disease caused by mutations in the gene that encodes galactosylceramidase, in which galactosylsphingosine (psychosine) accumulation drives demyelination in the central and peripheral nervous systems, ultimately progressing to death in early childhood. Gene therapy, alone or in combination with transplant, has been developed for almost two decades in mouse models, with increasing therapeutic benefit paralleling the improvement of next-generation adeno-associated virus (AAV) vectors. This effort has recently shown remarkable efficacy in the canine model of the disease by two different groups that used either systemic or cerebrospinal fluid (CSF) administration of AAVrh10 or AAV9. Building on our experience developing CSF-delivered, AAV-based drug products for a variety of neurodegenerative disorders, we conducted efficacy, pharmacology, and safety studies of AAVhu68 delivered to the CSF in two relevant natural Krabbe animal models, and in nonhuman primates. In newborn Twitcher mice, the highest dose (1 × 1011 genome copies [GC]) of AAVhu68.hGALC injected into the lateral ventricle led to a median survival of 130 days compared to 40.5 days in vehicle-treated mice. When this dose was administered intravenously, the median survival was 49 days. A single intracisterna magna injection of AAVhu68.cGALC at 3 × 1013 GC into presymptomatic Krabbe dogs increased survival for up to 85 weeks compared to 12 weeks in controls. It prevented psychosine accumulation in the CSF, preserved peripheral nerve myelination, ambulation, and decreased brain neuroinflammation and demyelination, although some regions remained abnormal. In a Good Laboratory Practice-compliant toxicology study, we administered the clinical candidate into the cisterna magna of 18 juvenile rhesus macaques at 3 doses that displayed efficacy in mice. We observed no dose-limiting toxicity and sporadic minimal degeneration of dorsal root ganglia (DRG) neurons. Our studies demonstrate the efficacy, scalability, and safety of a single cisterna magna AAVhu68 administration to treat Krabbe disease. ClinicalTrials.Gov ID: NCT04771416.

Krabbe disease: A personal perspective and hypothesis.

Introduction: Krabbe disease (KD) or globoid cell leukodystrophy (GLD) is one of the lysosomal disorders affecting central and peripheral nervous systems (CNS and PNS). It is caused by mutations on the galactocerebrosidase (GALC) gene. Affected individuals accumulate undegraded substrates and suffer from neuroinflammation. Methods: Hematopoietic stem cell transplantation (HSCT) has been partially successful in treating patients with KD when accomplished prior to the onset of symptoms. The success is credited to the ability of the hematopoietic stem cells in providing some GALC enzyme to the CNS and eradicating potential neuroinflammation. Combination of the HSCT with some other GALC-providing strategies has shown synergistic effects in the treatment of the mouse model of this disease. Results: Here, the possibility of eliminating HSCT in the treatment of human patients and replacing it with a single therapy that will provide sufficient GALC enzyme to the nervous systems is suggested. Such treatment, if started during the asymptomatic stage of the disease, not only may eradicate the enzyme deficiency, but may also keep any neuroinflammation at bay. Conclusion: Successful treatment of the KD may be possible by restoring consistent and sufficient GALC expression in CNS and PNS.

A novel compound heterozygous mutation in GALC associated with adult-onset Krabbe disease: case report and literature review.

Krabbe disease (KD) is a rare autosomal recessive lipid storage leukodystrophy. It is caused by deficient enzyme activity resulting from mutations of the ß-galactocerebrosidase (GALC) gene. KD is distinguished into subtypes based on the age of onset; these are early infantile, late infantile, juvenile, and adult-onset. We report a case of a 47-year-old Caucasian man with a 2-year history of muscle atrophy and weakness in both hands associated with pyramidal signs and mild spasticity in the lower limbs. An extensive work-up led this motor neuron disease-like disorder to be diagnosed as adult-onset KD. The patient was found to be compound heterozygous for two GALC mutations (p.G286D and p.Y490N). These two rare missense mutations have previously been reported with other heterozygous mutations. However, their co-occurrence in a KD patient is novel. From the perspective of this case, we review the current literature on compound heterozygous mutations in adult-onset KD and their phenotypic variability.

Clinical and genetic characteristics of adolescent and adult Krabbe disease / 中华神经科杂志

Objective:To investigate the clinical and genetic characteristics of patients with late-onset subtypes (adolescent or adult) of Krabbe disease.Methods:The clinical data of 7 patients with Krabbe disease admitted to Shanghai Jiao Tong University Affiliated Sixth People′s Hospital and Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from September 2006 to June 2021 were analyzed and Sanger sequencing of the galactosylceramidase (GALC) gene (NM_000153) and detection of the activity of GALC were conducted. A total of 61 cases of Krabbe disease reported in domestic literature were reviewed and summarized.Results:Among the 7 patients with Krabbe disease, there were 4 males and 3 females. All of them had lower limb weakness or walking difficulty as the initial symptoms, and presented as spastic paraplegia. The symptoms were relatively mild in patients with late onset. There were 4 out of 5 patients undergoing magnetic resonance imaging examination, who showed abnormal signals: 2 had brain atrophy and the remaining 2 had white matter lesions. A total of 5 GALC gene mutations were detected by genetic analysis. Among these, c.1901T>C (p.L634S), c.908C>T(p.S303F) and c.461C>A(p.P154H) are known variants, while c.50_51insTT (p.M17Ifs) and c.1130delT(p.L337X) are novel variants reported for the first time in this paper.Conclusions:Krabbe disease is a rare neurodegenerative disease with phenotypic heterogeneity, which is inherited in an autosomal recessive mode. The severity of clinical manifestations of Krabbe disease is correlated with the age of onset.

Compound heterozygous pathogenic variants in the GALC gene cause infant-onset Krabbe disease.

BACKGROUND: Krabbe disease, also called globoid cell leukodystrophy, is an autosomal recessive disease caused by a deficiency of lysosomal galactocerebrosidase. Infantile Krabbe occurring before 12 months of age accounts for most cases. Typical clinical features include irritability, seizures, peripheral neuropathy, and progressive neurodegeneration. METHODS: We collected and summarized the clinical and genetic data of an 8-month-old boy who demonstrated Krabbe disease onset at around 6 months. Potential pathogenic variants were screened by whole exome sequencing, and effects of candidate variants on alternative transcript and truncated protein were further validated at the RNA and protein level. RESULTS: Galactocerebrosidase activity was nearly absent in his blood, and whole exome sequencing revealed compound heterozygous variants [NM_000153.4: (c.658C>T); (c.328+5G>T)] in galactosylceramidase (GALC). The variant c.328+5G>T was predicted to alter splicing, and the abnormal isoform transcript was validated by observation of abnormal RNA isoforms. The variant c.658C>T was predicted to cause truncation of the protein, which was validated by western blotting. CONCLUSIONS: Our findings revealed compound heterozygous variants with solid experimental results for Krabbe disease and provides strong evidence for further Krabbe disease screening and clinical consulting. As a rare inherited systemic disorder, genetic variants in Krabbe disease should be investigated, as experimental validation for clinical diagnosis is needed.