Late juvenile-onset Krabbe's disease

Axonopathy is a compounding factor in the pathogenesis of Krabbe disease

Loss-of-function of the lysosomal enzyme galactosyl-ceramidase causes the accumulation of the lipid raft-associated sphingolipid psychosine, the disruption of postnatal myelination, neurodegeneration and early death in most cases of infantile Krabbe disease. This work presents a first study towards understanding the progression of axonal defects in this disease using the Twitcher mutant mouse. Axonal swellings were detected in axons within the mutant spinal cord as early as 1 week after birth. As the disease progressed, more axonopathic profiles were found in other regions of the nervous system, including peripheral nerves and various brain areas. Isolated mutant neurons recapitulated axonal and neuronal defects in the absence of mutant myelinating glia, suggesting an autonomous neuronal defect. Psychosine was sufficient to induce axonal defects and cell death in cultures of acutely isolated neurons. Interestingly, axonopathy in young Twitcher mice occurred in the absence of demyelination and of neuronal apoptosis. Neuronal damage occurred at later stages, when mutant mice were moribund and demyelinated. Altogether, these findings suggest a progressive dying-back neuronal dysfunction in Twitcher mutants.

Increasing exotropia and decreasing vision in a school-aged boy

An 8-year-old boy presented with bilateral visual loss and an increasing exotropia, and later developed deteriorating school performance. Magnetic resonance imaging of the head showed bilateral, symmetric, T2, and FLAIR white matter abnormalities in the parieto-occipital regions. Elevated serum very long chain fatty acids confirmed the diagnosis of X-linked adrenoleukodystrophy. Ophthalmologists should be aware of the diagnosis in boys with visual loss, hyperactivity, behavioral changes, and deterioration in school performance. Visual loss may be the presenting or predominant feature in X-linked adrenoleukodystrophy.

Allogeneic stem cell transplantation for the treatment of lysosomal and peroxisomal metabolic diseases

This is a review of the clinical responses and prospectus of new therapies following use of allogeneic hematopoietic stem cell transplantation for the treatment of the following disorders: Hurlers syndrome (MPS 1-H), globoid cell leukodystrophy (GLD; Krabbes disease), adrenoleukodystrophy, metachromatic leukodystrophy, Wolmans disease, I-cell disease (mucolipidosis II; MLS-II), alpha-mannosidosis, fucosidosis, Niemann-Pick B/A disease, Slys disease (MPS VII), Gauchers disease (Gaucher-II-III), Battens disease, Farbers disease, Sanfilippo syndrome (MPS-III), Hunters disease (MPS-II), Maroteaux-Lamy syndrome (MPS-VI), and aspartylglucosaminuria (AGU). Over 500 patients with lysosomal and peroxisomal metabolic storage diseases due to deficiency of primary enzymes have been treated with hematopoietic stem cell transplantation since the initial patient was treated a quarter of century ago. Normal enzymatic activity has been robust and continuous over these years without the need for any medication. Proof of principle has been reported for multiple positive effects including that of the reconstruction of the central nervous system. Furthermore, the excellent engraftment rate along with significantly diminished graft-vs-host-disease needs to be emphasized. The genetic diseases enumerated above have remarkable differences from those discussed elsewhere in this issue of Seminars in Immunopathology. Each has a greater genetic heterogeneity. Misdiagnosis resulting in delay of treatment and further decline of function and ultimate quality of life occurs almost all the time. Neonatal screening of these diseases will be mandatory to vastly improve outcomes. Plans are being implemented to use dried blood spots on filter paper, as is commonly done for many other genetic diseases. Many new therapies are being adopted which should enhance positivity and acceptance of treatment by hematopoietic stem cell transplantation.

Hematopoietic stem-cell transplantation in globoid-cell leukodystrophy

BACKGROUND

Globoid-cell leukodystrophy is caused by a deficiency of galactocerebrosidase, which results in progressive central nervous system deterioration. We investigated whether allogeneic hematopoietic stem-cell transplantation can provide a source of leukocyte galactocerebrosidase and thereby prevent the decline of central nervous system function in patients with the disease.

METHODS

Five children with globoid-cell leukodystrophy (one with the infantile type and four with late-onset disease) were treated with allogeneic hematopoietic stem-cell transplantation. Measurement of leukocyte galactocerebrosidase levels, neurologic examinations, neuropsychological tests, magnetic resonance imaging of the central nervous system, cerebrospinal fluid protein assays, and neurophysiologic measurements were performed before and after transplantation, with follow-up ranging from one to nine years.

RESULTS

Engraftment of donor-derived hematopoietic cells occurred in all patients and was followed by restoration of normal leukocyte galactocerebrosidase levels. In the four patients with late-onset disease, the central nervous system deterioration was reversed, and in the patient with the infantile form of the disease, signs and symptoms have not appeared. Magnetic resonance imaging showed a decrease in signal intensity in the three patients with late-onset disease who were assessed both before and after transplantation. Abnormalities in cerebrospinal fluid total protein levels were corrected in three patients with late-onset disease and substantially reduced in the patient with the infantile form.

CONCLUSIONS

Central nervous system manifestations of globoid-cell leukodystrophy can be reversed by allogeneic hematopoietic stem-cell transplantation.

Juvenile Krabbe's Leukodystrophy precipitated by influenza A infection

Juvenile Krabbe's disease, a neurometabolic disorder, presented as an acute demyelinating episode characterised by an abnormal gait. The neurological presentation was preceded by influenza A infection.