Creutzfeldt-Jakob disease in Austria: an autopsy-controlled study.

BACKGROUND: Definite diagnosis of prion diseases or transmissible spongiform encephalopathies (TSEs) requires neuropathology, usually at autopsy. Epidemiology of human TSEs has relied on definite as well as 'probable' cases in which neuropathological confirmation is lacking, usually because of low autopsy rates in most countries. METHODS: In Austria, an active surveillance program for human prion diseases was established in 1996. Since then, more than 900 referrals were analyzed. Postmortem investigation of brain tissue is mandatory in every suspect case of TSE. Thus, epidemiological data on TSEs from Austria may serve as autopsy-controlled reference for countries with lower autopsy rates. RESULTS: The total number of TSE cases in Austria since 1969 is 206. The average yearly mortality for the active surveillance period from 1996 to 30 June 2006 is 1.39 per million, with the highest rates for Vienna (2.37) compared with other provinces. Eighty-five percent of definite TSEs were classified as sporadic Creutzfeldt-Jakob disease (sCJD). We observed a significant linear increase in the mean age at death of 0.6 years per calendar year. Clinical diagnostic surveillance criteria had a sensitivity and specificity of 82.7 and 80.0% for probable CJD, respectively, and a positive predictive value of 80.5% for probable and 38.9% for 'possible' CJD. Alternative neuropathological diagnoses in suspect cases included Alzheimer's disease with or without Lewy body pathology, vascular encephalopathy, metabolic encephalopathies and viral or limbic encephalitis. CONCLUSION: The steady increase in mortality rates, especially in old age groups, most likely reflects improved case ascertainment due to active surveillance causing higher awareness of the medical community. In comparison with other European countries, it is reassuring to note that the overall death rate of TSEs does not differ from the Austrian autopsy-controlled data, thus confirming the value of clinical surveillance criteria.

Diagnosis of X-linked adrenoleukodystrophy in blood leukocytes.

OBJECTIVES: Our aim was to replace cultured skin fibroblasts in the diagnosis of X-linked adrenoleukodystrophy (X-ALD) by peripheral blood cells. DESIGN AND METHODS: Very long chain fatty acids (VLCFAs) were analyzed in leukocytes from X-ALD patients, heterozygotes, and controls using gas chromatography-mass spectrometry (GC-MS). Immunofluorescence for adrenoleukodystrophy protein (ALDP) was performed in mononuclear blood cell preparations of X-ALD patients known to be ALDP negative in fibroblasts, heterozygote relatives of these patients, and controls. RESULTS: All X-ALD patients were distinguishable from controls by VLCFA analysis in leukocytes. 91.7% of heterozygotes were identified by combined VLCFA analysis in leukocytes and plasma. All patients investigated lacked ALDP immunoreactivity in mononuclear cells, while heterozygotes showed mosaic patterns of positive and negative cells. CONCLUSION: Determination of VLCFAs by GC-MS in combination with ALDP immunofluorescence in peripheral blood cells provides a fast and minimally invasive diagnostic method for X-ALD, which, in contrast to plasma analysis, is independent of alimentary influences. Notably, joint evaluation of leukocytes and plasma considerably improves the identification of heterozygotes.

Quantification of α-galactosidase activity in intact leukocytes.

BACKGROUND: Mutations of the α-galactosidase (α-Gal) A gene in Fabry disease lead to a severe disturbance in glycosphingolipid catabolism. The atypical clinical picture of Fabry disease hampers diagnosis, resulting in a delayed start of therapy. Current tests utilize leukocyte lysates to evaluate the activity of α-Gal A. It has never been investigated whether cell homogenisation is necessary. METHODS: Isolated leukocyte subsets were incubated with the α-Gal substrate methylumbelliferyl-α-D galactopyranosid (MU-Gal) and substrate conversion was measured by fluorimetry. Specificity of the reaction was evaluated using the α-Gal inhibitor deoxygalactonojirimycin (DGJ). The novel procedure was compared to the standard method. A reference population and Fabry patients were tested. RESULTS: Substrate conversion in intact leukocytes was a function of substrate concentration, cell number and time and could be inhibited by DGJ. Monocytes showed the highest enzyme activity among leukocyte populations. The novel procedure highly correlated with the standard method. Both Fabry hemizygotes and heterozygotes showed reduced substrate conversion. CONCLUSION: We here present a novel sensitive, fast and simple procedure for the evaluation of α-Gal activity suitable to identify enzyme deficiencies in Fabry patients. Furthermore, we show for the first time that leukocyte subtypes have different α-Gal activities.

Peroxisomal localization of the proopiomelanocortin-derived peptides beta-lipotropin and beta-endorphin.

The peptide hormones ACTH, MSHs, ß-lipotropin (ß-LPH), and ß-endorphin are all derived from the precursor molecule proopiomelanocortin (POMC). Using confocal laser microscopy and immunoelectron microscopy in human pituitary gland, we demonstrate a peroxisomal localization of ß-endorphin and ß-LPH in cells expressing the peroxisomal ATP-binding cassette-transporter adrenoleukodystrophy protein (ALDP). The peroxisomal localization of ß-LPH and ß-endorphin was not restricted to the pituitary gland but was additionally found in other human tissues that express high levels of ALDP, such as dorsal root ganglia, adrenal cortex, distal tubules of kidney, and skin. In contrast to the peptide hormones ß-LPH and ß-endorphin, which are derived from the C terminus of POMC, the N-terminal peptides ACTH, α-MSH, and γ-MSH were never detected in peroxisomes. This novel peroxisomal localization of ß-endorphin and ß-LPH in ALDP-positive cells was confirmed by costaining with ALDP and the peroxisomal marker catalase. Moreover, peroxisomal sorting of ß-LPH could be modeled in HeLa cells by ectopic expression of a POMC variant, modified to allow cleavage and release of ß-LPH within the secretory pathway. Although ß-LPH and ß-endorphin were only associated with peroxisomes in cells that normally express ALDP, the transporter activity of ALDP is not necessary for the peroxisomal localization, as demonstrated in tissues of X-linked adrenoleukodystrophy patients lacking functional ALDP. It remains to be elucidated whether and how the peroxisomal localization of POMC-derived hormones has a role in the endocrine dysfunction of peroxisomal disease.

Distribution and cellular localization of adrenoleukodystrophy protein in human tissues: implications for X-linked adrenoleukodystrophy.

Defects of adrenoleukodystrophy protein (ALDP) lead to X-linked adrenoleukodystrophy (X-ALD), a disorder mainly affecting the nervous system white matter and the adrenal cortex. In the present study, we examine the expression of ALDP in various human tissues and cell lines by multiple-tissue RNA expression array analysis, Western blot analysis, and immunohistochemistry. ALDP-encoding mRNA is most abundant in tissues with high energy requirements such as heart, muscle, liver, and the renal and endocrine systems. ALDP selectively occurs in specific cell types of brain (hypothalamus and basal nucleus of Meynert), kidney (distal tubules), skin (eccrine gland, hair follicles, and fibroblasts), colon (ganglion cells and epithelium), adrenal gland (zona reticularis and fasciculata), and testis (Sertoli and Leydig cells). In pituitary gland, ALDP is confined to adrenocorticotropin-producing cells and is significantly reduced in individuals receiving long term cortisol treatment. This might indicate a functional link between ALDP and proopiomelanocortin-derived peptide hormones.

Mutations c.459+1G>A and p.P426L in the ARSA gene: prevalence in metachromatic leukodystrophy patients from European countries.

In this multicentre study, we examined the prevalence of two mutations in the arylsulfatase A (ARSA) gene, i.e., c.459+1G>A and p.P426L, in 384 unrelated European patients presenting with different types of metachromatic leukodystrophy (MLD). In total, c.459+1G>A was found 194 times among the 768 investigated ARSA alleles (25%), whereas p.P426L was identified 143 times (18.6%). Thus, these two mutations accounted for 43.8% of investigated MLD alleles. Mutation c.459+1G>A was most frequent in late-infantile MLD patients (40%), while p.P426L was most frequent in adults (42.5%), which is consistent with earlier observations, although p.P426L was also found in a few late-infantile patients (0.9%), and c.459+1G>A was present in some adults (9%). Mutation c.459+1G>A is more frequent in countries situated at the western edges of Europe, i.e., in Great Britain and Portugal, and also in Belgium, Switzerland, and Italy, which is visible as a strand ranging from North to South, and additionally in Czech and Slovak Republics. Mutation p.P426L is most prevalent in countries assembled in a cluster containing the Netherlands, Germany, and Austria. In other Central European countries, the frequency of both c.459+1G>A and p.P426L ranges from 8 to 37.5%. Our study has confirmed that c.459+1G>A and p.P426L are the most frequently found MLD-causing mutations in Europe. The data about their prevalence reflect the population variability in Europe.