Hospitalization Burden and Incidence of Krabbe Disease

OBJECTIVE

The purpose of our study was to understand the healthcare burden and incidence of Krabbe disease (Krabbe).

METHODS

Retrospective analysis of Krabbe patients identified October 1, 2015 through December 31, 2020, ages birth through age 3, evaluated in two national databases. We estimated point prevalence and incidence from year 2016 data.

RESULTS

We identified 98 unique Krabbe patients with 736 visits including 260 were inpatient admissions. Total healthcare charges were $51.5 million dollars. We determined a point prevalence of 34 68 Krabbe patients in 2016 ages 0 3 years. This estimates a birth incidence of ~1 in 310,000 live births. Significance: Krabbe disease patients had over $51 million in health care charges and hundreds of hospitalizations. Estimated prevalence and birth incidence is similar to rates observed from newborn screening. Our findings show the tremendous health impacts of Krabbe disease, and provide guidance for efforts in screening and treatment planning.

Krabbe disease: Neurophysiologic studies and MRI correlations

BACKGROUND

Krabbe disease (KD) is a rare hereditary leukodystrophy affecting children mostly in the first 6 months of life; later onset has been reported as well.

OBJECTIVE

To review abnormalities in neurophysiologic studies in children with KD and determine if there is a correlation between these studies and disease severity as measured by MRI scans.

METHODS

KD patients with at least one neurophysiologic study and one MRI scan at the authors' institution were reviewed. Relationships between KD type, neurophysiologic studies, and severity of disease as measured by MRI were explored.

RESULTS

Data were available for 26 children: 20 with early infantile KD (EIKD) and 6 with late-onset KD (LOKD). Flash visual evoked potentials were abnormal in 53% of EIKD children, whereas none of the LOKD children had an abnormal study. Brainstem auditory evoked potentials were abnormal in 88% of EIKD and 40% of LOKD children. EEGs were abnormal in 65% of EIKD and 33% of LOKD children. Nerve conduction studies were abnormal in all children with EIKD and in 20% of LOKD children. Abnormal neurophysiologic studies correlated with more extensive disease as measured by MRI scans.

CONCLUSIONS

Children with early infantile Krabbe disease and late-onset Krabbe disease have different patterns of abnormalities in neurophysiologic studies. These studies offer an objective means of assessing KD and correlate well with disease severity measured by MRI scans.

Brain-stem auditory and visual evoked potentials in children with Krabbe disease

OBJECTIVE

There are few reports in the literature detailing brain-stem auditory and visual evoked potentials (BAEP and VEP) in children with Krabbe disease (KD). The purpose of this study was to provide a descriptive analysis of the BAEP and VEP findings in these children.

METHODS

Charts of children with KD were reviewed. BAEP and VEP studies performed on these children were reviewed; findings in the early infantile and late onset KD (EIKD, LOKD, respectively) groups were also examined. Likelihood ratios (LR) for the neurophysiologic tests being abnormal in the various groups were also determined.

RESULTS

BAEP abnormalities were seen in 15/17 (88%) children with EIKD and 2/5 (40%) children with LOKD, LR statistically significant. In the EIKD group, all 13 symptomatic children had an abnormal BAEP, whereas 2/4 (50%) of the pre-symptomatic children had similar findings, LR statistically significant. VEP abnormalities were noted in 8/15 (53%) children with EIKD and none of the children with LOKD, LR statistically significant. In the EIKD group, the 8/12 (67%) symptomatic children had an abnormal VEP, whereas none of the pre-symptomatic children did, LR statistically significant. Subgroup analyses of the LOKD subgroups did not yield significant findings.

CONCLUSIONS

BAEP abnormalities are among the first objective indications of central nervous system disease in children with EIKD. VEP abnormalities occur later in the course of the illness. Both tests are less helpful in children with LOKD.

SIGNIFICANCE

BAEP and VEP testing is helpful in objective evaluation of children with KD.

Allogeneic bone marrow transplantation for infantile globoid-cell leukodystrophy (Krabbe's disease)

A 4-month-old-girl affected by early expression of Krabbe's disease was treated with allogeneic bone marrow transplantation (BMT). The stem cell donor was her heterozygous HLA-identical mother. The central nervous system (CNS) involvement at diagnosis was evident, but minimal. After BMT the child presented a severe hypotonia and an acute tetraventricular hydrocephalus; she died 180 days after the BMT with progressive severe neurologic deterioration. Leukocyte galactocerebrosidase (GALC) activity was present at donor levels 20 days after BMT. Full donor chimerism was evident 18 days after BMT. This report confirms that in early onset "Krabbe's syndrome" if the diagnosis is delayed after the birth, the progression of the neurologic deterioration is not reversed by BMT. It is to be demonstrated if a very early hemopoietic stem cell transplantation during the first weeks of life, could be appropriate and efficacious.

Residual galactosylsphingosine (psychosine) beta-galactosidase activities and associated GALC mutations in late and very late onset Krabbe disease

BACKGROUND

Krabbe disease (globoid-cell leukodystrophy; GLD) is caused by mutations in the GALC gene. Beta-galactocerebrosidase (GALC) is a specific beta-galactosidase which is defective in GLD. About 90% of GLD patients have an infantile course by fatal cerebral demyelination, but 10% have a later onset (LOGLD) of symptoms and survive for one or several decades.

METHODS

Activities of GALC towards galactosylceramide (GC) and galactosylsphingosine (psychosine; PS) were determined in white blood cells and cultured fibroblasts derived from GLD patients and controls using tritium-labelled natural substrates. In the galactosylsphingosine (psychosine) beta-galactosidase (GALC-PS) assay, a thin layer chromatographic technique was used to separate enzymatically released radioactive galactose.

RESULTS

Both galactosylceramide beta-galactosidase (GALC-GC) and GALC-PS activities were reduced by at least 85% of the normal in all but 2 of the 10 GLD patients studied. In particular, one 23-year-old severely demyelinated LOGLD patient was strongly deficient (11% of the normal) in GALC-GC but apparently normal for GALC-PS activity. This patient's GALC genotype was the 30-kb-deleted/502T allele combined with a wild-type allele in the 1637C background known to slightly reduce GALC-GC activity. Further, of six LOGLD patients, both of 62- and 63-year-old brothers had the deleted allele combined with an 809G>A mutated 1637C allele. The sibs had strongly reduced GALC-GC and GALC-PS activities but became clinically remarkable only in their 50s with a severe mental downhill course in one of them.

CONCLUSIONS

A GALC genotype with one deleted and one polymorphic GALC activity-reducing allele can lead to enzymatic and clinical signs of LOGLD in the absence of marked GALC-PS deficiency. If an active PS hydrolysis in the fibroblasts of a LOGLD patient also reflected such hydrolysis in the brain, the psychosine hypothesis for GLD may need to be revised.

Krabbe disease--clinical profile

OBJECTIVE

To study clinical features and investigations of children with Krabbe Disease (KD).

DESIGN

Retrospective.

SETTING

Genetic Clinic of a tertiary care teaching hospital.

METHODS

Hospital records of patients with enzymatically confirmed KD were analyzed with respect to their clinical features and investigations including neuroimaging (CT-scan and/or MRI). Galactocerebrosidase (GALC) activity was estimated photometrically in the peripheral blood leukocytes.

RESULTS

Nine children (age ranging from 2 1/2 months to 8 years) were studied, of which 5 had the classical infantile disease, 3 had late infantile form and one was diagnosed as juvenile KD. GALC levels in peripheral blood leukocytes were low or absent in all. Most of the children with infantile disease presented with neurodegeneration, seizures or fever. Optic atrophy was uncommon in our series (present only in a single case). Majority of the cases had elevated cerebrospinal fluid (CSF) protein levels and peripheral neuropathy on nerve conduction (NC) studies. Findings typical of KD were noted in 7 patients who underwent magnetic resonance imaging (MRI). The sole patient with juvenile disease presented with developmental delay and progressive spastic quadriparesis.

CONCLUSION

Krabbe disease should be considered in the differential diagnosis of early infantile onset of neurodegeneration with seizures. Likewise, older children with progressive ataxia or spastic quadriparesis in whom the etiology remains obscure, must be investigated for Krabbe disease. MRI can be diagnostic in absence of availability of enzyme diagnosis.

Leukodystrophy incidence in Germany

Through a survey of all departments of pediatrics, neurology and neuropathology in Germany, we calculated the incidence of all major forms of leukodystrophy. Only diagnoses based on specific biochemical tests in association with typical findings and/or neuroradiologically proven white matter involvement were accepted. In accordance with these strict criteria, 617 cases of leukodystrophy were found (incidence of all forms: app. 2.0/100,000). Minimal incidence was estimated at 0.8/100,000 for adrenoleukodystrophy/adrenomyeloneuropathy (ALD/AMN), 0.6/100,000 for metachromatic leukodystrophy (MLD), and 0.6/100,000 for Krabbe disease. Thus ALD/AMN is apparently underdiagnosed in Germany. A considerable proportion of leukodystrophies could not be classified in spite of adequate diagnostic procedures in experienced centers.

Autosomal recessive diseases among Palestinian Arabs

As a consequence of the high consanguinity rate among the Palestinian Arabs, many recessive disorders are present with a relatively high frequency. In a survey of 2000 different Palestinian Arab families who visited our genetic clinic, in 601 an autosomal recessive disease was diagnosed or strongly suspected. The distribution of these disorders was not uniform and some disorders, such as Krabbe disease, were found at high frequency in only a small part of the population. For some other disorders, a high prevalence was also reported among Palestinian Arabs living in other regions, for example, beta thalassaemia, Bardet-Biedl syndrome, Meckel syndrome, autosomal recessive congenital hydrocephalus, and recessive osteopetrosis. In addition, as another consequence of the high consanguinity rate, two different autosomal recessive diseases were diagnosed within the same sibship in 17 of the Palestinian Arab families.

Krabbe disease in Israel

Over a period of 15 years, 18 infants affected with Krabbe disease were diagnosed in Israel. None of the patients were Jews. Six were Druze from a large kindred in which a very high incidence of the disease was previously reported. The 12 other patients were Moslem Arabs; 7 were from two adjacent villages and most of them were found to be related, originating from a large kindred in which the incidence of the disease is 1/130 live births. Three other patients were from a third large kindred that also had a high incidence of Krabbe disease. Israel's population includes communities in which a high incidence of lysosomal diseases has been found. The incidence of these diseases in Israel may be reduced by delineating the populations at risk. With respect to Krabbe disease, as reported here, the tests for heterozygote detection are not sufficiently accurate for a screening of the populations at risk. Prevention is possible only by prenatal diagnosis in the families at risk.

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.

Krabbe disease: increased incidence in a highly inbred community

Krabbe disease (globoid cell leukodystrophy) was found with very high incidence (6/1,000 live births) in a large Druze kindred in Israel. The clinical data on 12 of the affected children demonstrated clinical variability even though these children are homozygous for the same mutation by descent from a common ancestor.

Clinical aspects of globoid cell and metachromatic leukodystrophies

This paper describes the clinical, diagnostic, genetic and incidence aspects of globoid cell leukodystrophy and metachromatic leukodystrophy, the two least rare and most distinctive types among the leukodystrophies. It is based on experiences with 32 Swedish cases of globoid cell leukodystrophy (1953-1967) and 16 Swedish cases of metachromatic leukodystrophy (1956-1969). In both disorders it is now possible to make a correct diagnosis during life through various laboratory and biopsy procedures. An autosomal recessive inheritance is present in both of the disorders. The incidence of Krabbe's disease was found to be about 2:100,000 newborns in Sweden. The corresponding figure for metachromatic leukodystrophy is unknown at this time but is probably of about the same magnitude. This is the case in Northern Sweden.