Cerebrospinal fluid and serum glycosphingolipid biomarkers in canine globoid cell leukodystrophy (Krabbe Disease).

Globoid cell leukodystrophy (GLD, Krabbe disease, Krabbe's disease) is caused by genetic mutations in the gene encoding, galactosylceramidase (GALC). Deficiency of this enzyme results in central and peripheral nervous system pathology, and is characterized by loss of myelin and an infiltration of globoid cells. The canine model of GLD provides a translational model which faithfully recapitulates much of the human disease pathology. Targeted lipidomic analysis was conducted in serum and cerebrospinal fluid (CSF) over the lifetime of GLD affected and normal canines, and in brain tissue at humane endpoint to better understand disease progression and identify potential biomarkers of disease. Psychosine, a substrate of GALC and primary contributor to the pathology in GLD, was observed to be significantly elevated in the serum and CSF by 2 or 4 weeks of age, respectively, and steadily increased over the lifetime of affected animals. Importantly, psychosine concentration strongly correlated with disease severity. Galactosylceramide, glucosylceramide, and lactosylceramide were also found to be elevated in the CSF of affected animals and increased with age. Psychosine and galactosylceramide were found to be significantly increased in brain tissue at humane endpoint. This study identified several biomarkers which may be useful in the development of therapeutics for GLD.

Early infantile Krabbe disease: results of the World-Wide Krabbe Registry.

New York State began screening for Krabbe disease in 2006 to identify infants with Krabbe disease before symptom onset. Because neither galactocerebrosidase activity nor most genotypes reliably predict phenotype, the World Wide Registry was developed to determine whether other clinical/neurodiagnostic data could predict early infantile Krabbe disease in the newborn screening population. Data on disease course, galactocerebrosidase activity, DNA mutations, and initial neurodiagnostic studies in 67 symptomatic children with early infantile Krabbe disease were obtained from parent questionnaires and medical records. Initial signs included crying/irritability, cortical fisting, and poor head control. Galactocerebrosidase activity was uniformly low. Eight of 17 manifested novel mutations. Ninety-two percent (n = 25) exhibited elevated cerebrospinal fluid protein; 76% (n = 42) demonstrated abnormal magnetic resonance images; 67% (n = 15) exhibited abnormal computed tomography findings; 43% (n = 28) produced abnormal electroencephalogram findings; 100% (n = 5) demonstrated abnormal nerve conduction velocities; 83% (n = 6) produced abnormal brainstem evoked responses; and 50% (n = 6) exhibited abnormal visual evoked responses. One, 2, and 3 year survivals were 60%, 26%, and 14%, respectively. Although most symptomatic patients with the early infantile phenotype manifested abnormal cerebrospinal fluid protein, magnetic resonance imaging, brainstem evoked responses, and nerve conduction velocities, studies of affected children may be normal. Other biomarkers are needed to predict phenotype in the newborn screening population.

Sensitivity and specificity of decreased CSF asialotransferrin for eIF2B-related disorder.

OBJECTIVE: This is a study estimating diagnostic accuracy of CSF asialotransferrin to transferrin ratio measurement in eIF2B related disorders by using clinical evaluation and EIF2B mutation analysis as the reference standard. eIF2B-related disorder is a relatively common leukodystrophy with broad phenotypic variation that is caused by mutations in any of the five EIF2B genes. There is a need for a simple and clinically valid screening tool for physicians evaluating patients with an unclassified leukodystrophy. METHODS: CSF two-dimensional gel (2DG) electrophoresis analyses to measure asialotransferrin to transferrin ratios were performed in 60 subjects including 6 patients with documented EIF2B gene mutations, patients with other types of leukodystrophy, and patients with no leukodystrophy. RESULTS: All six patients with mutation proven eIF2B-related disease showed low to nearly undetectable amounts of asialotransferrin in their CSF when compared to 54 unaffected controls by CSF 2DG analyses in this study. eIF2B-like patients, with clinically similar presentations but no mutations in EIF2B1-5, were distinguished from patients with mutations in EIF2B1-5 by this biomarker. Patients with mutations in EIF2B1-5 had asialotransferrin/transferrin ratio levels significantly different from the group as a whole (p < 0.001). Using 8% asialotransferrin/transferrin ratio as a cutoff, this biomarker has a 100% sensitivity (95% CI = 52-100%) and 94% specificity (95% CI = 84-99%). CONCLUSION: Decreased asialotransferrin/transferrin ratio in the CSF of patients with eIF2B-related disorder is highly sensitive and specific. This rapid (<48 hours) and inexpensive diagnostic tool for eIF2B-related disorders has the potential to identify patients with likely eIF2B-related disorder for mutation analysis.

Possible use of CSF glycosphingolipids for the diagnosis and therapeutic monitoring of lysosomal storage diseases.

We used a high-performance liquid chromatography method to measure CSF gangliosides, neutral glycolipids, and sulfatides in patients with lysosomal storage disorders. These measurements could be done on less than 1 milliliter of CSF. In patients with GM1 gangliosidosis, GM1 ganglioside was increased, and in GM2 gangliosidosis patients, GM2 ganglioside was increased in CSF. Sulfatides were variably increased in CSF early in the course of the disease and appeared to be a means of monitoring patients, following bone marrow transplantation. Fabry's disease patients showed an increase in globotriaosylceramide, but Krabbe's disease patients did not demonstrate an increase in galactosylceramide. This study suggests that CSF glycosphingolipid measurements may prove helpful in the diagnosis and monitoring of lysosomal storage diseases.

Doença de Krabbe (leucodistrofia a células globóides): a propósito de cinco observaçöes / Krabbe's disease (globoid cell leukodystrophy): apropos of 5 cases

Foi realizado estudo clínico de 5 observaçöes da doença de Krabbe (leucidistrofia a células globóides). O diagnóstico de certeza, seja pelo estudo neuropatológico pós mortem (2 casos), seja pela dosagem enzimática em fibroblastos em cultura (2 casos), foi alcançado em 4 observaçöes. A biópsia de nervo periférico foi realizada nos 5 casos e o estudo ultrastrutural revelou, em todos, alteraçöes características da doença de Krabbe. Os autores chamam a atençäo para os principais dados clínicos e laboratoriais que sugerem o diagnóstico da doença, mesmo na impossibilidade da realizaçäo de exame ultrastrutural de nervo periférico e das dosagens enzimáticas, estas näo realizadas em nosso país

[Krabbe's disease (globoid cell leukodystrophy). Apropos of 5 cases]. / Doença de Krabbe (leucodistrofia a células globóides). A propósito de cinco observações.

A clinical study on five cases of Krabbe's disease (globoid cell leukodystrophy) was performed. A final diagnosis was done either with post-mortem study (two cases) or by enzymatic assays carried on cultured fibroblasts (two cases). Peripheral nerve biopsy for electron microscopy was performed in all cases, and the ultrastructural alterations characteristics of Krabbe's disease were always found. The authors emphasize the suggestive clinical and laboratory data which enable the diagnosis of Krabbe's disease in the absence of the ultrastructural exam of peripheral nerve, or the enzymatic assays not performed in this country.

Symptomatology of late onset Krabbe's leukodystrophy: the European experience.

The authors present a study of 50 patients with late onset Krabbe's leukodystrophy (LOKL), including 27 from a pooled European Series collected in 1987, and 23 published between 1906 and 1987. In Europe, the disease appears to be relatively frequent in Sicily and exceedingly rare in Sweden. Most cases started before the age of 5 years. The initial signs consisted mainly of progressive motor impairment, although, characteristically, visual failure was the initial manifestation in 25% of patients. Low nerve conduction velocities and a high protein content in the CSF were only present in 50%. There was no age-linked symptomatic predominance. The pace and length of the disease was very variable, but in one-third of the children before the age of 3 the course was remarkably rapid. There was no difference in the residual activity of galactosylceramide galactosidase in LOKL compared to the early infantile form.

Late onset globoid leukodystrophy: unusual clinical and CSF findings.

During a febrile upper respiratory tract illness this 4 year old boy developed left hemiparesis, which progressed to loss of walking and even of sitting finally to tetraplegia. The cerebrospinal fluid protein pattern showed blood-brain barrier damage with additional intrathecal IgG synthesis. The symptoms responded to steroid therapy but resumed and worsened on withdrawal. Only late, when visual evoked potentials and nerve conduction velocity proved to be impaired, was Krabbe disease diagnosed on the assay of cultured fibroblasts for galactocerebroside-beta-galactosidase. We discuss the significance of possible endogenous production of IgG in the CNS.