Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare progressive neurological disorder ... more Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare progressive neurological disorder caused by Lamin B1 duplication (LMNB1). Our aim was to investigate longitudinally the pattern of the autonomic dysfunction and the degree of neuropsychological involvement. Three related ADLD patients and one asymptomatic carrier of LMNB1 duplication underwent a standardized evaluation of autonomic nervous system, including cardiovascular reflexes, pharmacological testing, microneurography, skin biopsy, Metaiodobenzylguanidine scintigraphy and a complete neuropsychological battery. An early neurogenic orthostatic hypotension was detected in all patients and confirmed by a low rise in noradrenaline levels on Tilt Test. However infusion of noradrenaline resulted in normal blood pressure rise as well as the infusion of clonidine. At the insulin tolerance test the increase in adrenaline resulted pathological in two out three patients. Microneurography failed to detect muscle sympathetic nerve activity bursts. Skin biopsy revealed a poor adrenergic innervation, while cardiac sympathetic nerves were normal. None of ADLD patients showed a global cognitive deficit but a selective impairment in the executive functions. Autonomic disorder in ADLD involves selectively the postganglionic sympathetic system including the sympatho-adrenal response. Cognitive involvement consisting in an early impairment of executive tasks that might precede brain MR abnormalities.
The Heidenhain variant defines a peculiar clinical presentation of sporadic Creutzfeldt-Jakob dis... more The Heidenhain variant defines a peculiar clinical presentation of sporadic Creutzfeldt-Jakob disease (sCJD) characterized by isolated visual disturbances at disease onset and reflecting the early targeting of prions to the occipital cortex. Molecular and histopathological typing, thus far performed in 23 cases, has linked the Heidenhain variant to the MM1 sCJD type. To contribute a comprehensive characterization of cases with the Heidenhain variant, we reviewed a series of 370 definite sCJD cases. Eighteen patients (4.9% ) fulfilled the selection criteria. Fourteen of them belonging to sCJD types MM1 or MM1+2C had a short duration of isolated visual symptoms and overall clinical disease, a high prevalence of periodic sharp-waved complexes in EEG, and a marked increase of cerebrospinal fluid proteins t-tau and 14-3-3 levels. In contrast, three cases of the MM 2C or MM 2+1C types showed a longer duration of isolated visual symptoms and overall clinical disease, non-specific EEG findings, and cerebrospinal fluid concentration below threshold for the diagnosis of "probable" CJD of both 14-3-3 and t-tau. However, a brain DWI-MRI disclosed an occipital cortical hyperintensity in the majority of examined cases of both groups. While confirming the strong linkage with the methionine genotype at the polymorphic codon 129 of the prion protein gene, our results definitely establish that the Heidenhain variant can also be associated with the MM 2C sCJD type in addition to the more common MM1 type. Likewise, our results highlight the significant differences in clinical evolution and laboratory findings between cases according to the dominant PrPSc type (type 1 versus type 2).
More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the pen... more More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the penetrance-the probability that a carrier of the purported disease-causing genotype will indeed develop the disease-is generally unknown. We assess the impact of variants in the prion protein gene (PRNP) on the risk of prion disease by analyzing 16,025 prion disease cases, 60,706 population control exomes, and 531,575 individuals genotyped by 23andMe Inc. We show that missense variants in PRNP previously reported to be pathogenic are at least 30 times more common in the population than expected on the basis of genetic prion disease prevalence. Although some of this excess can be attributed to benign variants falsely assigned as pathogenic, other variants have genuine effects on disease susceptibility but confer lifetime risks ranging from <0.1 to ~100%. We also show that truncating variants in PRNP have position-dependent effects, with true loss-of-function alleles found in healthy older...
The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) ... more The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) may be challenging at disease onset. Levodopa responsiveness helps distinguish the two groups, but studies evaluating this issue using objective standardized tests are scanty. We retrospectively examined the extent of levodopa response by an objective kinetic-dynamic test in a series of patients prospectively followed up for a parkinsonian syndrome and eventually diagnosed as MSA-P or PD. Sixteen MSA-P and 31 PD patients under chronic levodopa therapy received a first morning fasting dose of levodopa/benserazide (100/25 mg) or levodopa/carbidopa (125/12.5 or 100/25 mg) and underwent simultaneous serial assessments of plasma levodopa concentration and alternate finger tapping frequency up to 3 h post dosing. The main levodopa pharmacodynamic variables were the maximum percentage increase in tapping frequency over baseline values (ΔTapmax %) and the area un...
adult-onset autosomal dominant leukodystrophy (ADLD) is a rare inherited disorder due to a duplic... more adult-onset autosomal dominant leukodystrophy (ADLD) is a rare inherited disorder due to a duplication of lamin-B1 (LMNB1) gene. The aim of this study was to investigate brain metabolic and microstructural alterations by using advanced MR techniques. we performed brain MR scans including single-voxel proton-MR Spectroscopy ((1)H-MRS) of the lateral ventricles and parietal white matter and diffusion tensor imaging (DTI) in 4 subjects with LMNB1 gene duplication, 6 non-mutated relatives and 7 unrelated healthy controls. Cervical and thoracic spinal cord MR was performed in three symptomatic subjects with LMNB1 mutation. All participants underwent clinical and neuropsychological evaluation. all subjects with LMNB1 gene duplication presented pathological accumulation of lactate in lateral ventricles CSF and no alterations of brain white matter absolute metabolites concentrations or metabolites/Cr ratios. We found increased white matter intra- and extracellular water transverse relaxation times. Tract-based spatial statistics analysis detected a significantly reduced fractional anisotropy in the genu of the corpus callosum in mutated cases compared to unrelated healthy controls and non-mutated relatives. Moreover, we detected different degrees of the typical white matter signal intensity alterations and brain and spinal atrophy at conventional MRI in symptomatic subjects with LMNB1 mutation. A mild impairment of executive functions was found in subjects with LMNB1 gene mutation. in subjects with LMNB1 gene duplication, we found a pathological increase in CSF lactate, likely due to active demyelination along with glial activation, and microstructural changes in the genu of the corpus callosum possibly underpinning the mild neuropsychological deficits.
The authors investigated a patient who died of apparent sporadic Creutzfeldt-Jakob disease (CJD) ... more The authors investigated a patient who died of apparent sporadic Creutzfeldt-Jakob disease (CJD) but carried a R208H substitution in the prion protein (PrP). The patient phenotype was indistinguishable from typical sporadic CJD (i.e., MM1 subtype). In addition, pathologic PrP, PrP(Sc), originated from both the normal and the mutated PRNP allele and had the same characteristics as PrP(Sc) type 1. The authors propose that the R208H mutation influences disease susceptibility without significantly affecting PrP(Sc) properties or disease phenotype.
Dickson/Neurodegeneration: The Molecular Pathology of Dementia and Movement Disorders, 2011
... Piero Parchi , 1 Sabina Capellari and 1 Pierluigi Gambetti 2 1Department of Neurological Scie... more ... Piero Parchi , 1 Sabina Capellari and 1 Pierluigi Gambetti 2 1Department of Neurological Sciences, University of Bologna, Bologna, Italy 2Institute of Pathology and National Prion Disease Pathology Surveillance Center, Case Western ... 2 Medori R , Tritschler HJ , LeBlanc A et al ...
The abnormal form of the prion protein has increased resistance to protease digestion and is inso... more The abnormal form of the prion protein has increased resistance to protease digestion and is insoluble in non-ionic detergents. The normal prion protein is modified by the non-obligatory addition of two N-linked glycans. One pathogenic mutation, Thr to Ala at residue 183 of the human prion protein, blocks addition of the first glycan to the Asp residue 181. This mutation has been reported to result in intracellular retention of the mutant protein and its acquisition of pathogenic properties, presumably due to the lack of the glycan. We report that the lack of the N-linked glycan at residue 181 is not responsible for the block in transport or the acquisition of pathogen-like properties, rather, the Thr to Ala mutation is itself the probable cause of the pathogenic phenotype.
Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare progressive neurological disorder ... more Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare progressive neurological disorder caused by Lamin B1 duplication (LMNB1). Our aim was to investigate longitudinally the pattern of the autonomic dysfunction and the degree of neuropsychological involvement. Three related ADLD patients and one asymptomatic carrier of LMNB1 duplication underwent a standardized evaluation of autonomic nervous system, including cardiovascular reflexes, pharmacological testing, microneurography, skin biopsy, Metaiodobenzylguanidine scintigraphy and a complete neuropsychological battery. An early neurogenic orthostatic hypotension was detected in all patients and confirmed by a low rise in noradrenaline levels on Tilt Test. However infusion of noradrenaline resulted in normal blood pressure rise as well as the infusion of clonidine. At the insulin tolerance test the increase in adrenaline resulted pathological in two out three patients. Microneurography failed to detect muscle sympathetic nerve activity bursts. Skin biopsy revealed a poor adrenergic innervation, while cardiac sympathetic nerves were normal. None of ADLD patients showed a global cognitive deficit but a selective impairment in the executive functions. Autonomic disorder in ADLD involves selectively the postganglionic sympathetic system including the sympatho-adrenal response. Cognitive involvement consisting in an early impairment of executive tasks that might precede brain MR abnormalities.
The Heidenhain variant defines a peculiar clinical presentation of sporadic Creutzfeldt-Jakob dis... more The Heidenhain variant defines a peculiar clinical presentation of sporadic Creutzfeldt-Jakob disease (sCJD) characterized by isolated visual disturbances at disease onset and reflecting the early targeting of prions to the occipital cortex. Molecular and histopathological typing, thus far performed in 23 cases, has linked the Heidenhain variant to the MM1 sCJD type. To contribute a comprehensive characterization of cases with the Heidenhain variant, we reviewed a series of 370 definite sCJD cases. Eighteen patients (4.9% ) fulfilled the selection criteria. Fourteen of them belonging to sCJD types MM1 or MM1+2C had a short duration of isolated visual symptoms and overall clinical disease, a high prevalence of periodic sharp-waved complexes in EEG, and a marked increase of cerebrospinal fluid proteins t-tau and 14-3-3 levels. In contrast, three cases of the MM 2C or MM 2+1C types showed a longer duration of isolated visual symptoms and overall clinical disease, non-specific EEG findings, and cerebrospinal fluid concentration below threshold for the diagnosis of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;probable&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; CJD of both 14-3-3 and t-tau. However, a brain DWI-MRI disclosed an occipital cortical hyperintensity in the majority of examined cases of both groups. While confirming the strong linkage with the methionine genotype at the polymorphic codon 129 of the prion protein gene, our results definitely establish that the Heidenhain variant can also be associated with the MM 2C sCJD type in addition to the more common MM1 type. Likewise, our results highlight the significant differences in clinical evolution and laboratory findings between cases according to the dominant PrPSc type (type 1 versus type 2).
More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the pen... more More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the penetrance-the probability that a carrier of the purported disease-causing genotype will indeed develop the disease-is generally unknown. We assess the impact of variants in the prion protein gene (PRNP) on the risk of prion disease by analyzing 16,025 prion disease cases, 60,706 population control exomes, and 531,575 individuals genotyped by 23andMe Inc. We show that missense variants in PRNP previously reported to be pathogenic are at least 30 times more common in the population than expected on the basis of genetic prion disease prevalence. Although some of this excess can be attributed to benign variants falsely assigned as pathogenic, other variants have genuine effects on disease susceptibility but confer lifetime risks ranging from <0.1 to ~100%. We also show that truncating variants in PRNP have position-dependent effects, with true loss-of-function alleles found in healthy older...
The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) ... more The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) may be challenging at disease onset. Levodopa responsiveness helps distinguish the two groups, but studies evaluating this issue using objective standardized tests are scanty. We retrospectively examined the extent of levodopa response by an objective kinetic-dynamic test in a series of patients prospectively followed up for a parkinsonian syndrome and eventually diagnosed as MSA-P or PD. Sixteen MSA-P and 31 PD patients under chronic levodopa therapy received a first morning fasting dose of levodopa/benserazide (100/25 mg) or levodopa/carbidopa (125/12.5 or 100/25 mg) and underwent simultaneous serial assessments of plasma levodopa concentration and alternate finger tapping frequency up to 3 h post dosing. The main levodopa pharmacodynamic variables were the maximum percentage increase in tapping frequency over baseline values (ΔTapmax %) and the area un...
adult-onset autosomal dominant leukodystrophy (ADLD) is a rare inherited disorder due to a duplic... more adult-onset autosomal dominant leukodystrophy (ADLD) is a rare inherited disorder due to a duplication of lamin-B1 (LMNB1) gene. The aim of this study was to investigate brain metabolic and microstructural alterations by using advanced MR techniques. we performed brain MR scans including single-voxel proton-MR Spectroscopy ((1)H-MRS) of the lateral ventricles and parietal white matter and diffusion tensor imaging (DTI) in 4 subjects with LMNB1 gene duplication, 6 non-mutated relatives and 7 unrelated healthy controls. Cervical and thoracic spinal cord MR was performed in three symptomatic subjects with LMNB1 mutation. All participants underwent clinical and neuropsychological evaluation. all subjects with LMNB1 gene duplication presented pathological accumulation of lactate in lateral ventricles CSF and no alterations of brain white matter absolute metabolites concentrations or metabolites/Cr ratios. We found increased white matter intra- and extracellular water transverse relaxation times. Tract-based spatial statistics analysis detected a significantly reduced fractional anisotropy in the genu of the corpus callosum in mutated cases compared to unrelated healthy controls and non-mutated relatives. Moreover, we detected different degrees of the typical white matter signal intensity alterations and brain and spinal atrophy at conventional MRI in symptomatic subjects with LMNB1 mutation. A mild impairment of executive functions was found in subjects with LMNB1 gene mutation. in subjects with LMNB1 gene duplication, we found a pathological increase in CSF lactate, likely due to active demyelination along with glial activation, and microstructural changes in the genu of the corpus callosum possibly underpinning the mild neuropsychological deficits.
The authors investigated a patient who died of apparent sporadic Creutzfeldt-Jakob disease (CJD) ... more The authors investigated a patient who died of apparent sporadic Creutzfeldt-Jakob disease (CJD) but carried a R208H substitution in the prion protein (PrP). The patient phenotype was indistinguishable from typical sporadic CJD (i.e., MM1 subtype). In addition, pathologic PrP, PrP(Sc), originated from both the normal and the mutated PRNP allele and had the same characteristics as PrP(Sc) type 1. The authors propose that the R208H mutation influences disease susceptibility without significantly affecting PrP(Sc) properties or disease phenotype.
Dickson/Neurodegeneration: The Molecular Pathology of Dementia and Movement Disorders, 2011
... Piero Parchi , 1 Sabina Capellari and 1 Pierluigi Gambetti 2 1Department of Neurological Scie... more ... Piero Parchi , 1 Sabina Capellari and 1 Pierluigi Gambetti 2 1Department of Neurological Sciences, University of Bologna, Bologna, Italy 2Institute of Pathology and National Prion Disease Pathology Surveillance Center, Case Western ... 2 Medori R , Tritschler HJ , LeBlanc A et al ...
The abnormal form of the prion protein has increased resistance to protease digestion and is inso... more The abnormal form of the prion protein has increased resistance to protease digestion and is insoluble in non-ionic detergents. The normal prion protein is modified by the non-obligatory addition of two N-linked glycans. One pathogenic mutation, Thr to Ala at residue 183 of the human prion protein, blocks addition of the first glycan to the Asp residue 181. This mutation has been reported to result in intracellular retention of the mutant protein and its acquisition of pathogenic properties, presumably due to the lack of the glycan. We report that the lack of the N-linked glycan at residue 181 is not responsible for the block in transport or the acquisition of pathogen-like properties, rather, the Thr to Ala mutation is itself the probable cause of the pathogenic phenotype.
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Papers by Sabina Capellari