Exome sequencing is a useful diagnostic tool for complicated forms of hereditary spastic paraplegia

Hereditary spastic paraplegias constitute a heterogeneous group of neurodegenerative diseases encompassing pure and complicated forms, for which at least 52 loci and 31 causative genes have been identified. Although mutations in the SPAST gene explain approximately 40% of the pure autosomal dominant forms, molecular diagnosis can be challenging for the sporadic and recessive forms, which are often complicated and clinically overlap with a broad number of movement disorders. The validity of exome sequencing as a routine diagnostic approach in the movement disorder clinic needs to be assessed. The main goal of this study was to explore the usefulness of an exome analysis for the diagnosis of a complicated form of spastic paraplegia. Whole-exome sequencing was performed in two Spanish siblings with a neurodegenerative syndrome including upper and lower motor neuron, ocular and cerebellar signs. Exome sequencing revealed that both patients carry a novel homozygous nonsense mutation in exon 15 of the SPG11 gene (c.2678G>A; p.W893X), which was not found in 584 Spanish control chromosomes. After many years of follow-up and multiple time-consuming genetic testing, we were able to diagnose these patients by making use of whole-exome sequencing, showing that this is a cost-efficient diagnostic tool for the movement disorder specialist.

Characterization of dopaminergic dysfunction in familial progressive supranuclear palsy: an 18F-dopa PET study

We analyzed (18)F-dopa PET data from 11 members of kindreds with familial progressive supranuclear palsy (PSP) to characterize their cerebral dopaminergic dysfunction. Three clinically-affected PSP patients showed reduced (18)F-dopa uptake in the striatum, orbitofrontal cortex and amygdala. One asymptomatic subject exhibited progressive putamen dopaminergic dysfunction. 60% of subjects with abnormal (18)F-dopa scans developed PSP subsequently. This is the first in vivo documentation of cortical dopaminergic deficiency in PSP. Reduced striatal (18)F-dopa uptake in susceptible relatives may predict later clinical disease.

Suppression of Parkin enhances nigrostriatal and motor neuron lesion in mice over-expressing human-mutated tau protein

Abnormal deposition of protein tau takes place in the brain of patients with several neurodegenerative diseases. Few of these patients present frontotemporal dementia with parkinsonism and amyotrophy (FTDPA-17), an autosomal dominant tauopathy related to mutations of the gene that codes for protein tau, localized in chromosome 17. The great majority of patients with tauopathies such as Alzheimer's disease, sporadic frontotemporal dementia or progressive supranuclear palsy do not show a Mendelian pattern of inheritance. We have occasionally seen tauopathies in patients with parkin mutations and, therefore, hypothesized that the protein tau interacts with parkin. We have tested that hypothesis in mice with combined genetic modifications of tau (over-expression of human tau with three mutations known to produce FTDPA-17) and parkin (deleted) proteins. Homozygote parkin null or over-expressing mutated-human tau mice have subtle behavioral and molecular abnormalities but do not express a clinical phenotype of neurodegenerative disease. Mice with combined homozygous mutations of these two genes show progressively abnormal walking already noticeable at 3 months of age, loss of dopamine and dopamine markers in striatum, nuclear tau immunoreactive deposits in motor neurons of the spinal cord, abnormal expression of glial markers and enhanced levels of pro-apoptotic proteins; findings that were absent or less pronounced in homozygote animals with deletions of parkin or over-expression of tau. The double transgenic mice do not express normal mechanisms of adaptation to stress such as increased levels of GSH and Hsp-70. In addition, they have reduced levels of CHIP-Hsc70, a complex known to attenuate aggregation of tau and to enhance ubiquitination of phosphorylated tau. We have found high levels of phosphorylated tau in parkin-/-+tau(VLW) mice and a relative decrease of the inactivated pSer9 to total GSK-3 levels. Our data reveal that there are interactions between tau and parkin that could be relevant for the pathogenesis and treatment of tauopathies. Similarly, we hope that the double transgenic parkin-/-+tau(VLW) mice could be useful for testing of compounds with putative therapeutic value in human tauopathies.

[Klüver-Bucy syndrome as the initial symptom of adult-type ceroid lipofuscinosis (Kufs' disease)]

AIMS

The purpose of this paper is to report the case of a patient with Kluver-Bucy syndrome caused by adult-type ceroid lipofuscinosis (Kufs' disease) and to review the literature dealing with the causes of this syndrome.

CASE REPORT

A 38-year-old male examined because of behavioural changes and cognitive impairment. Brain biopsy findings were characteristic of adult-type ceroid lipofuscinosis. This patient fulfilled the criteria of Kufs' disease, since he had mixed clinical features belonging to both type A (neuropsychiatric disorders) and B (aphasia-apraxia-agnosia syndrome) of the disease. The initial symptoms included several clinical features of Klüver-Bucy syndrome (probable visual agnosia, apathy, increased sexual activity, lack of sexual inhibition, hypermetamorphopsia, increased oral behaviour and changes in dietary habits).

CONCLUSIONS

Adult-type ceroid lipofuscinosis is an infrequent clinical entity that is difficult to diagnose owing to the absence of peripheral biological markers and the need to confirm such a diagnosis by means of a histopathological study.

[Aphasias for verbal and sign languages are due to lesions of nearly localised but not identical brain regions of the left hemisphere]

OBJECTIVES

To study the characteristics of verbal and sign language aphasia in a patient fluent in both languages, who had had a recent left hemisphere stroke as well as to localise the site responsible for Spanish sign language aphasia.

PATIENT AND METHODS

56 years old male, with risk factors for stroke, who presented an episode of sudden onset aphasia and right hemiplegia that partially recovered in a few hours. The residual deficit of language was explored with a detailed protocol that included comprehension, denomination, oral and phonetic praxis, propositional and automatic spontaneous language, reading and writing tasks. The examination of verbal and sign language was video-recorded. The lesion was localised by magnetic resonance imaging 24 days after the stroke.

RESULTS

The patient, whose infarction involved the superior temporal gyrus and sylvian operculum, presented similar abnormalities for comprehension of complex sentences, many phonemic paraphasias and no trouble to repeat single words. Oral language was not fluent, but sign language was quite fluent with a rich vocabulary, but with semantic paraphasias, agrammatism and without self-criticism for his own mistakes.

CONCLUSIONS

The pattern of oral and sign language alterations is partially different, more for expressive than perceptive discourse, although both types of aphasias are caused by lesions of the left hemisphere. The regions responsible for these abnormalities of both symbolic languages are localised close to each other, but not in the same place.

[Glia conditioned medium offers protection against the toxicity induced by 6-OH-dopamine in vivo]

INTRODUCTION

Glia conditioned medium (GCM) is neurotrophic for dopaminergic (DA) neurons and protects against MPP+ toxicity in vitro. We present the data from the first study in vivo of the effects of GCM.

MATERIAL AND METHODS

The restorative effects were examined in rats with lesions produced by 6-hydroxy-dopamine (6-OH-DA) in the medial longitudinal fasciculus. At four weeks, animals with an apomorphine induced rotation rate above three per minute were randomised for infusion with GCM, defined medium (DM) or saline through a striatal cannula for two weeks. To investigate the protective effects of GCM, the animals received a striatal injection of GCM or vehicle at the same time as the lesion was induced by 6-OH-DA and were sacrificed three weeks later.

RESULTS

In the experiments on the restorative effect, the GCM infusion produced a significant increase in dopamine (DA) levels on the side with the lesion, in the limbic system (455.8 108.4 ng/g of tissue) and in the striatum (242.1 69.2 ng/g of tissue), as compared with the controls (110.8 36,4 and 108.4 22 ng/g). In the experiments on the protective effect, GCM induced higher levels of DA, 3,4-dihydroxyphenylacetic acid and 3 methoxytyramine (3-MT). In both models, the apomorphine induced rotation in animals with lesions caused by 6-OH-DA and treated with GCM was lower than that of the animals infused with DM or saline.

CONCLUSIONS

These experiments show that GCM has protective and restorative effects in an experimental model of Parkinson's disease.

Bradykinesia in early Huntington's disease

BACKGROUND

Huntington's disease (HD) is generally considered a hyperkinetic disorder, although hypokinetic features are part of the motor syndrome. Moreover, the striatum is considered to play a key role in initiating and executing motor programs and achieving optimal scheduling in response generation. Controversial results regarding the association between clinical features and markers of progression of the disease might be the result of inadequate restriction of clinical signs to the choreatic syndrome.

OBJECTIVE

To determine the relationship of neurologic motor and cognitive indices in patients with HD with intrinsic neuronal loss in the striatum, as measured using raclopride C11 and PET.

PATIENTS AND METHODS

A cross-sectional study was performed on 11 patients with mild HD (stages 0-2). Motor (Unified Huntington's Disease Rating Scale [UHDRS], saccadic and tapping speed) and cognitive (verbal fluency, Trail Making Test, Stroop Test, Symbol Digit Modalities Test, Conditioned Associative Learning Test, and silhouette identification and object decision of the Visual Object and Space Perception battery) scores were correlated with raclopride C11 binding.

RESULTS

Bradykinesia (a summation of five items of the UHDRS motor scale) was the best predictor for stage, that is, functional capacity, and showed a highly significant relationship with putaminous D2 binding (r = -0.94) and with CAG expansion length x years of age (r = 0.96). The exclusion of two patients with a rigid-akinetic HD variant did not alter these coefficients. Chorea was less well correlated than bradykinesia with D2 binding in all striatal regions. Performance on different cognitive tests, especially in timed tasks, was highly correlated with raclopride C11 binding in caudate nucleus and ventral striatum.

CONCLUSION

Loss of D2 binding in the striatum is highly correlated with the deficit in fast motor and cognitive processing in patients with early Huntington's Disease. Thus, impairment of rapid execution of adequate responses to environmental changes seems to be a common manifestation of striatal disorders.

The tau gene A0 allele and progressive supranuclear palsy

BACKGROUND

Recent studies have shown an association between a polymorphic tandem repeat allele, located in intron 9, of the tau gene and progressive supranuclear palsy (PSP).

OBJECTIVE

To investigate this tau polymorphism in individuals with a clinical diagnosis of sporadic or familial PSP as well as in cases confirmed by pathology.

METHODS

We analyzed the frequency of tau intronic polymorphism, the presence of linkage in two families with multiple cases of PSP, the splicing of exon 10, and direct sequence of the tau gene.

RESULTS

We found that patients with a clinical diagnosis of sporadic or familial PSP and individuals with PSP confirmed by neuropathology have greater prevalence of the A0 allele and A0/A0 genotype than controls. This finding, however, was also true for asymptomatic relatives of individuals with PSP. Linkage analysis in familial PSP excluded the location of the gene in the region 17q21. Furthermore, no significant differences were found in the level of expression of exon 10 in PSP, A0/A0 brain with respect to Alzheimer A3/A3 brain. We found no mutations in the tau gene in individuals with familial PSP.

CONCLUSIONS

A mutation in the tau gene was not the primary cause of familial PSP. The role of tau and the tau A0 allele in white PSP patients remains unknown, although it may represent a genetic risk factor for several neurodegenerative disorders.

Clinical correlation of striatal 1H MRS changes in Huntington's disease

OBJECTIVE

To study the clinical significance of metabolic alterations as measured in vivo with proton MRS in the striatum of patients with Huntington's disease (HD).

METHODS

Localized, single-voxel MRS was performed on the basal ganglia of 10 HD patients (4 presymptomatic gene carriers and 6 akinetic patients) and 5 age-matched healthy individuals. Metabolite quantification was performed by referring the areas of the respective spectral peaks to that of water in the analyzed voxel. The spectroscopic findings were correlated with motor and cognitive performance in several specific tests and with the length of the CAG repeat expansion normalized for age.

RESULTS

N-acetylaspartate (NAA) and creatine were reduced markedly in both groups of patients, particularly in the advanced group (approximately 60%), but the decrease was also significant in presymptomatic patients (approximately 30%) whose motor and cognitive performances were within the normal range. Both metabolites correlated highly with the motor score of the Unified Huntington's Disease Rating Scale and with computed measurements of saccadic and tapping speed. Creatine reduction was also well correlated with performance in cognitive timed tasks and with the length of CAG expansion (r = -0.81).

CONCLUSION

The creatine signal appears to be an interesting marker for progression in HD and could be useful in assessing therapeutic outcome, particularly during the initial stages when most clinical indices are still within the normal range.

Clinical genetics of familial progressive supranuclear palsy

Recent studies have shown that progressive supranuclear palsy (PSP) could be inherited, but the pattern of inheritance and the spectrum of the clinical findings in relatives are unknown. We here report 12 pedigrees, confirmed by pathology in four probands, with familial PSP. Pathological diagnosis was confirmed according to recently reported internationally agreed criteria. The spectrum of the clinical phenotypes in these families was variable including 34 typical cases of PSP (12 probands plus 22 secondary cases), three patients with postural tremor, three with dementia, one with parkinsonism, two with tremor, dystonia, gaze palsy and tics, and one with gait disturbance. The presence of affected members in at least two generations in eight of the families and the absence of consanguinity suggests autosomal dominant transmission with incomplete penetrance. We conclude that hereditary PSP is more frequent than previously thought and that the scarcity of familial cases may be related to a lack of recognition of the variable phenotypic expression of the disease.

[A comparative study of the effect of bromocriptine and pergolide on Parkinson disease]

INTRODUCTION

Bromocriptine and pergolide are the two dopamine agonists most often used in Parkinson's disease. Few comparative studies of the efficacy of both compounds are available.

OBJECTIVE

To compare the relative efficacy of bromocriptine and pergolide in patients with Parkinson's disease and intermediate stages of evolution.

METHODS

Open label study of 5-months of duration. The first agonist was given for two months and, after a period of substitution of one month, the second agonist was also maintained for two months.

RESULTS

Pergolide was more effective than bromocriptine for global scores of the UPDRS, total motor scores, clinical symptoms, akinesia and rigidity. Both compounds were equal effective for the treatment of tremor and fluctuations. Both agonists produced similar side effects.

CONCLUSIONS

At the ration 1/10 mg/day pergolide was more effective than bromocriptine in patients with Parkinson's disease at intermediate stages of evolution.

Familial progressive supranuclear palsy. Description of a pedigree and review of the literature

We describe a family with autosomal dominant progressive supranuclear palsy (PSP) involving five generations which was confirmed in one patient. The proband presented with progressive slowness at age 53 years, followed by ocular palsy, loss of balance, axial dystonia, dysphagia and dysarthria, and died at age 59 years. Neuropathological examination revealed moderate numbers of neurofibrillary tangles without prominent senile plaques in the cortex, and neuronal loss, gliosis and moderate to severe accumulation of tangles in the basal ganglia and brainstem. Other affected relatives, including the proband's sister, father, paternal uncle, and other members of earlier generations presented with non-characteristic akinetic syndromes, which progressed towards more typical PSP only after several years of disease. A review of the literature revealed six other families with neurodegenerative disorders associated with pathological findings compatible with PSP in at least one member. The clinical symptoms varied greatly between individuals in these families. The pattern of inheritance seems compatible with autosomal dominant transmission, although other patterns of transmission could not be excluded. We conclude that there is an autosomal dominant form of PSP and that the number of hereditary cases may be greater than previously thought. The rarity of familial cases of PSP could be attributed to diagnostic problems, including lack of recognition of atypical cases and death of the gene carriers before the age of appearance of the clinical symptoms. Large families with hereditary PSP could provide an adequate point of departure for investigation of the gene defect responsible for this disease.

L-dopa inhibits complex IV of the electron transport chain in catecholamine-rich human neuroblastoma NB69 cells

L-3,4-Dihydroxyphenylalanine (L-dopa) is toxic for human neuroblastoma cells NB69 and its toxicity is related to several mechanisms including quinone formation and enhanced production of free radicals related to the metabolism of dopamine via monoamine oxidase type B. We studied the effect of L-DOPA on activities of enzyme complexes in the electron transport chain (ETC) in homogenate preparations from the human neuroblastoma cell line NB69. As a preliminary step we compared the activity of ETC in cellular homogenates with that of purified mitochondria from NB69 cells and rat brain. Specific activities for complex I, complex II-III, and complex IV in NB69 cells were, respectively, 65, 96, and 32% of those in brain mitochondria. Complex I activity was inhibited in a dose-dependent way by 1-methyl-4-phenylpyridinium ion with an EC50 of approximately 150 microM. Treatment with 0.25 mM L-dopa for 5 days reduces complex IV activity to 74% of control values but does not change either complex I or citrate synthase. Ascorbic acid (1 mM), which protects NB69 cells from L-dopa-induced neurotoxicity, increases complex IV activity to 133% of the control and does not change other ETC complexes. Ascorbic acid also reverses L-dopa-induced reduction of complex IV activity in NB69 cells. This observation might indicate that the protection observed with ascorbic acid is related to complex IV activation. In vitro incubation with L-dopa (0.125-4 mM) for 2 min produced a dose-dependent reduction of complex IV without change in complex I and II-III activities.

Side effects of the catechol-O-methyl-transferase inhibitor Ro 40-7592 in rabbits

Catechol-O-methyl-transferase inhibitors are promising drugs in Parkinson's disease since these drugs enhance levodopa effects and increase their duration. However, since these compounds block a pathway for the peripheral metabolism of catecholamines, they may also produce side effects related to elevation of catecholamines in plasma. We investigated the adverse effects of Ro 40-7592 in rabbits and the relationship of Ro 40-7592 to norepinephrine plasma levels. Intravenous administration of Ro 40-7592 in rabbits induced elevation of norepinephrine plasma levels in old animals after bolus injection of a dose three times the highest dose actually recommended to be taken orally by humans. Though Ro 40-7592 appears safe for humans, special precautions may be needed in patients with a high risk of adrenergic hyperactivity.

Clinical and pharmacokinetic effects of a diet rich in insoluble fiber on Parkinson disease

In this study, the effects of a diet rich in insoluble fiber (DRIF) on motor disability and the peripheral pharmacokinetics of orally administered L-dopa in Parkinsonian patients with marked constipation are analyzed. We found a useful effect of a DRIF on plasma L-dopa concentration and motor function. The greatest effect on the plasma L-dopa levels was found early (at 30 and 60 min) after oral administration. There was a relationship between the improvement of constipation and the higher bioavailability of L-dopa. DRIF can be a coadjuvant treatment in patients with Parkinson's disease.

[Effect of a controlled low-protein diet on the pharmacological response to levodopa and on the plasma levels of L-dopa and amino acids in patients with Parkinson's disease]

Levodopa is the treatment of choice in Parkinson's disease, but a high percentage of patients develop complications in the response, including fluctuations, after some years of treatment. Although the origin of fluctuations is unknown, these could be, at least partly, attributed to pharmacokinetic factors. Aromatic aminoacids interfere in the absorption and brain penetration of levodopa, and lowering protein intake improves the quality of the response. The continuation of a low-protein diet is difficult for some patients. In this way, to know if these diet effects are noticeable in an acute period would be interesting, in order to select groups of patients who were susceptible to improve with this treatment. In this report we have studied the acute effect of a low protein diet on the pharmacological response to levodopa, and the plasmatic levels of L-Dopa, 3-OM-Dopa and large neutral aminoacids. Protein restriction improves clinical response to levodopa, although the mechanisms of this improvement remain unknown.

[Craniocervical dystonia and facial hemispasm: clinical and pharmacological characteristics of 52 patients]

The results obtained in a retrospective study on clinical and pharmacological aspects of 41 patients suffering craniocervical dystonia (24 with blepharospasm, 17 with torticollis) and 11 with spasm are here presented. Mean age of symptoms onset was 57.4, 43.8 and 55.8 years old respectively; this variable was comparatively higher in females than in males with torticollis. The prevalence of blepharospasm and hemifacial spasm was higher in females. A 38.7% of patients suffering blepharospasm also presented oromandibular dystonia (Meige's syndrome). Other abnormal movements less frequently associated were cephalic tremor, postural hand tremor and larynx dystonia. In three cases with blepharospasm there was family history of Parkinson's disease and in two cases with torticollis there was family history of essential tremor. The mean age of onset was lower in patients with clonic torticollis and the evolution time of symptoms was longer than in those who presented the tonic type. Clonic torticollis were less frequently associated to pain. Trihexyphenidyl (anticholinergic) was the most efficient drug in craniocervical dystonia, and clonazepam in facial hemispasm. In general, as earliest the age of onset was, as better the therapeutical response was.

[Clinical and epidemiologic characteristics of familial Parkinson disease]

We have studied 44 patients diagnosed of idiopathic Parkinson disease included in our database of rigid-akinetic syndromes. We have compared their demographic, environmental and clinical features with the ones that presented a group on 22 patients diagnosed of idiopathic Parkinson disease and had some first degree relatives with the same disease. Patients with familial Parkinson disease are distinguished from the ones that suffer from sporadic Parkinson disease because of an early start, greater consanguinity rate and greater frequency of a similar disease in their parents. Moreover, we have seen that familial Parkinson disease patients have drunk more water from wells during their lives than the ones that suffer sporadic Parkinson disease, present greater frequency of wide motoricity disorders, dystonia, night hypokinesia, fluctuations in relation to L-DOPA and greater frequency of early going grey. We have not found either epidemiologic data which could explain the appearance of familial cases or environmental causes which could produce familial Parkinson disease. Clinical differences between the two groups are likely due to an early start of symptoms in familial Parkinson disease cases. According to our data we could not conclude that between familial and sporadic Parkinson disease are significant differences in to justify two well-defined diseases. Even, the familial presentation of idiopathic Parkinson disease could be the normal form of Parkinson disease if long survival was a favourable factor of disease onset in pre-symptomatic persons.

Carbidopa dosage modifies L-dopa induced side effects and blood levels of L-dopa and other amino acids in advanced parkinsonism

Thirty-four patients with advanced Parkinson's disease showing intolerance to therapeutic doses of L-DOPA were treated with L-DOPA plus carbidopa at two different proportions. Ten patients preferred medication containing 10% carbidopa while 24 preferred 25% carbidopa. The increase of carbidopa reduced gastrointestinal disturbances and psychiatric side effects related to L-DOPA, but improvement of disability when measured according to objective tests was modest. Higher doses of carbidopa reduced peripheral DOPA metabolism and increased blood levels of tryptophan, 3-OM-DOPA and DOPA in relation to the administered dose.

Effects of 3-OM-dopa on monoamine metabolism in rat brain

We studied the effects of 3-methoxy, 4-hydroxy-phenylalanine (3-OM-dopa) on monoamine turnover, L-3-4-dihydroxy-phenylalanine (L-dopa) reversal of catecholamine depletion induced by alpha-methyl-paratyrosine (alpha-MT), and the passage of L-dopa across the blood-brain barrier of the rat brain. 3-OM-dopa did not affect monoamine turnover but interfered with restoration of dopamine levels by L-dopa. In addition, systemic 3-OM-dopa decreased brain uptake of 14C-L-dopa. High 3-OM-dopa blood levels may interfere with the therapeutic response to L-dopa in parkinsonism.