A Study of Dopaminergic Pathway in Neurologic Wilson Disease with Movement Disorder

Movement disorder (MD) is an important manifestation of neurologic Wilson disease (NWD), but there is a paucity of information on dopaminergic pathways. We evaluate dopamine and its receptors in patients with NWD and correlate the changes with MD and MRI changes. Twenty patients with NWD having MD were included. The severity of dystonia was assessed using BFM (Burke-Fahn-Marsden) score. The neurological severity of NWD was categorized as grades I to III based on the sum score of 5 neurological signs and activity of daily living. Dopamine concentration in plasma and CSF was measured using liquid chromatography-mass spectrometry, and D1 and D2 receptor expression at mRNA by reverse transcriptase polymerase chain reaction in patients and 20 matched controls. The median age of the patients was 15 years and 7 (35%) were females. Eighteen (90%) patients had dystonia and 2 (10%) had chorea. The CSF dopamine concentration (0.08 ± 0.02 vs 0.09 ± 0.017 pg/ml; p = 0.42) in the patients and controls was comparable, but D2 receptor expression was reduced in the patients (0.41 ± 0.13 vs 1.39 ± 1.04; p = 0.01). Plasma dopamine level correlated with BFM score (r = 0.592, p < 0.01) and D2 receptor expression with the severity of chorea (r = 0.447, p < 0.05). The neurological severity of WD correlated with plasma dopamine concentration (p = 0.006). Dopamine and its receptors were not related to MRI changes. The central nervous system dopaminergic pathway is not enhanced in NWD, which may be due to structural damage to the corpus striatum and/or substantia nigra.

Postsynaptic movement disorders: clinical phenotypes, genotypes, and disease mechanisms

Movement disorders comprise a group of heterogeneous diseases with often complex clinical phenotypes. Overlapping symptoms and a lack of diagnostic biomarkers may hamper making a definitive diagnosis. Next-generation sequencing techniques have substantially contributed to unraveling genetic etiologies underlying movement disorders and thereby improved diagnoses. Defects in dopaminergic signaling in postsynaptic striatal medium spiny neurons are emerging as a pathogenic mechanism in a number of newly identified hyperkinetic movement disorders. Several of the causative genes encode components of the cAMP pathway, a critical postsynaptic signaling pathway in medium spiny neurons. Here, we review the clinical presentation, genetic findings, and disease mechanisms that characterize these genetic postsynaptic movement disorders.

Novel Imaging Biomarkers for Huntington's Disease and Other Hereditary Choreas

PURPOSE OF THE REVIEW

Imaging biomarkers for neurodegenerative disorders are primarily developed with the goal to aid diagnosis, to monitor disease progression, and to assess the efficacy of disease-modifying therapies in support to clinical outcomes that may either show limited sensitivity or need extended time for their evaluation. This article will review the most recent concepts and findings in the field of neuroimaging applied to Huntington's disease and Huntington-like syndromes. Emphasis will be given to the discussion of potential pharmacodynamic biomarkers for clinical trials in Huntington's disease (HD) and of neuroimaging tools that can be used as diagnostic biomarkers in HD-like syndromes.

RECENT FINDINGS

Several magnetic resonance (MR) and positron emission tomography (PET) molecular imaging tools have been identified as potential pharmacodynamic biomarkers and others are in the pipeline after preclinical validation. MRI and 18F-fluorodeoxyglucose PET can be considered useful supportive diagnostic tools for the differentiation of other HD-like syndromes. New trials in HD have the primary goal to lower mutant huntingtin (mHTT) protein levels in the brain in order to reduce or alter the progression of the disease. MR and PET molecular imaging markers have been developed as tools to monitor disease progression and to evaluate treatment outcomes of disease-modifying trials in HD. These markers could be used alone or in combination for detecting structural and pharmacodynamic changes potentially associated with the lowering of mHTT.

Understanding the pathophysiology of hyperglycemia-associated chorea-ballism: a systematic review of positron emission tomography findings

Hyperglycemia-associated chorea-ballism (HCB) is an infrequent neurological syndrome whose pathophysiology remains poorly understood. Positron emission tomography (PET) studies have offered valuable information regarding regional glucose metabolism. The studies included were published between 1980-2017 and reported demographic, clinical, laboratory and imaging data from patients with HCB in whom a PET scan had been performed. Eleven patients were evaluated (women 82%, Asian origin 91%, mean age 71 years). The main findings were an increase in glucose metabolism at the contralateral motor cortex related to recent episodes of hemiballism-hemichorea in 2 patients, and an altered metabolism in the affected basal ganglia in all of them: decreased in 10 patients (91%) and increased in 1 (9%). However during the acute period the patients showed only an increased metabolism, or even no changes. Contrary to what has previously been suggested in a metabolic failure hypothesis, changes in glucose metabolism in the basal ganglia may not be a key factor in the pathogenesis of HCB, and may potentially be a direct result of histological changes such as cellular ischemia and gliosis related to HCB development.

Metabolic biology of 3-methylglutaconic acid-uria: a new perspective

Over the past 25 years a growing number of distinct syndromes/mutations associated with compromised mitochondrial function have been identified that share a common feature: urinary excretion of 3-methylglutaconic acid (3MGA). In the leucine degradation pathway, carboxylation of 3-methylcrotonyl CoA leads to formation of 3-methylglutaconyl CoA while 3-methylglutaconyl CoA hydratase converts this metabolite to 3-hydroxy-3-methylglutaryl CoA (HMG CoA). In "primary" 3MGA-uria, mutations in the hydratase are directly responsible for the accumulation of 3MGA. On the other hand, in all "secondary" 3MGA-urias, no defect in leucine catabolism exists and the metabolic origin of 3MGA is unknown. Herein, a path to 3MGA from mitochondrial acetyl CoA is proposed. The pathway is initiated when syndrome-associated mutations/DNA deletions result in decreased Krebs cycle flux. When this occurs, acetoacetyl CoA thiolase condenses two acetyl CoA into acetoacetyl CoA plus CoASH. Subsequently, HMG CoA synthase 2 converts acetoacetyl CoA and acetyl CoA to HMG CoA. Under syndrome-specific metabolic conditions, 3-methylglutaconyl CoA hydratase converts HMG CoA into 3-methylglutaconyl CoA in a reverse reaction of the leucine degradation pathway. This metabolite fails to proceed further up the leucine degradation pathway owing to the kinetic properties of 3-methylcrotonyl CoA carboxylase. Instead, hydrolysis of the CoA moiety of 3-methylglutaconyl CoA generates 3MGA, which appears in urine. If experimentally confirmed, this pathway provides an explanation for the occurrence of 3MGA in multiple disorders associated with compromised mitochondrial function.

Impaired pre-mRNA processing and altered architecture of 3' untranslated regions contribute to the development of human disorders

The biological fate of each mRNA and consequently, the protein to be synthesised, is highly dependent on the nature of the 3′ untranslated region. Despite its non-coding character, the 3′ UTR may affect the final mRNA stability, the localisation, the export from the nucleus and the translation efficiency. The conserved regulatory sequences within 3′ UTRs and the specific elements binding to them enable gene expression control at the posttranscriptional level and all these processes reflect the actual state of the cell including proliferation, differentiation, cellular stress or tumourigenesis. Through this article, we briefly outline how the alterations in the establishment and final architecture of 3′ UTRs may contribute to the development of various disorders in humans.

Identification and functional characterization of a novel mutation in the NKX2-1 gene: comparison with the data in the literature

BACKGROUND

NKX2-1 mutations have been described in several patients with primary congenital hypothyroidism, respiratory distress, and benign hereditary chorea, which are classical manifestations of the brain-thyroid-lung syndrome (BTLS).

METHODS

The NKX2-1 gene was sequenced in the members of a Brazilian family with clinical features of BTLS, and a novel monoallelic mutation was identified in the affected patients. We introduced the mutation in an expression vector for the functional characterization by transfection experiments using both thyroidal and lung-specific promoters.

RESULTS

The mutation is a deletion of a cytosine at position 834 (ref. sequence NM_003317) (c.493delC) that causes a frameshift with formation of an abnormal protein from amino acid 165 and a premature stop at position 196. The last amino acid of the nuclear localization signal, the whole homeodomain, and the carboxy-terminus of NKX2-1 are all missing in the mutant protein, which has a premature stop codon at position 196 (p.Arg165Glyfs*32). The p.Arg165Glyfs*32 mutant does not bind DNA, and it is unable to transactivate the thyroglobulin (Tg) and the surfactant protein-C (SP-C) promoters. Interestingly, a dose-dependent dominant negative effect of the p.Arg165Glyfs*32 was demonstrated only on the Tg promoter, but not on the SP-C promoter. This effect was also noticed when the mutation was tested in presence of PAX8 or cofactors that synergize with NKX2-1 (P300 and TAZ). The functional effect was also compared with the data present in the literature and demonstrated that, so far, it is very difficult to establish a specific correlation among NKX2-1 mutations, their functional consequence, and the clinical phenotype of affected patients, thus suggesting that the detailed mechanisms of transcriptional regulation still remain unclear.

CONCLUSIONS

We describe a novel NKX2-1 mutation and demonstrate that haploinsufficiency may not be the only explanation for BTLS. Our results indicate that NKX2-1 activity is also finely regulated in a tissue-specific manner, and additional studies are required to better understand the complexities of genotype-phenotype correlations in the NKX2-1 deficiency syndrome.

Hyperglycemic chorea-ballism or acute exacerbation of Huntington's chorea? Huntington's disease unmasked by diabetic ketoacidosis in type 1 diabetes mellitus

CONTENT

Hyperglycemic chorea-ballism is predominantly observed in older type 2 diabetic patients, and it is rare in type 1 diabetes and diabetic ketoacidosis (DKA). Huntington's disease (HD) is one of several genetic syndromes associated with diabetes, although the reported prevalence of the association varies. There are few opportunities for most physicians to diagnose early-stage HD.

OBJECTIVE

We describe bilateral hyperglycemic chorea-ballism in a 40-yr-old female type 1 diabetes patient with DKA and HD.

SETTING

The study was conducted in a tertiary care referral hospital.

RESULTS

On admission, the patient exhibited severe involuntary movement of bilateral extremities with DKA, and hyperglycemic chorea-ballism was diagnosed. She recovered from chorea-ballism with admission of fluids and insulin, but mild choreatic movement persisted in the upper extremities. Brain magnetic resonance imaging and DNA analysis revealed HD. Although it has been considered that depletion of striatal γ-aminobutyric acid (GABA) content is rare in DKA, it is largely decreased in HD. Therefore, it is probable that hyperglycemic chorea-ballism or exacerbation of Huntington's chorea resulted from transient depletion of GABA.

CONCLUSION

The present case provides important insights on the role of GABA in hyperglycemic chorea-ballism and on the clinical issues associated with HD diagnosis.

Diabetic striatal disease: clinical presentation, neuroimaging, and pathology

BACKGROUND

Unilateral movement disorders and contralateral neuroimaging abnormalities of the striatum have been sporadically reported as a rare syndrome associated with diabetes mellitus. Despite characteristic imaging findings and clinical manifestations, the mechanism underlying this syndrome is still unclear.

METHODS

Six patients with this syndrome were studied clinically and subjected to MRI neuroimaging; one underwent biopsy of the striatum, and another underwent additional MR spectroscopy at 3.0T and FDG-PET.

RESULTS

Neuroimaging findings were characterized by a T1-hyperintense unilateral lesion restricted to the striatum, contralateral to the symptomatic limbs. The biopsied striatum contained patchy necrotic tissue, severe thickening of all layers of arterioles, and marked narrowing of vessel lumens. Hyaline degeneration of the arteriolar walls, extravasation of erythrocytes, and prominent capillary proliferation were also notable, together with lymphocytic infiltration and macrophage invasion. In one patient, PET examination revealed decreased accumulation of FDG in the lesion. The MR spectrum for the diseased striatum revealed a decrease in the NAA/Cr ratio (1.35), normal Cho/Cr ratio (1.22), and a peak for myoinositol, while the spectrum on the contralateral site revealed a decrease in the NAA/Cr ratio (1.48), increase in Cho/Cr (1.32), but no peak for myoinositol.

CONCLUSION

The constellation of signs and symptoms and neuroimaging characteristics in previous reports and the six additional cases described here with neuropathological data and findings of MR spectroscopy appears unique enough to be termed "diabetic striatopathy." This syndrome appears in poorly controlled diabetics due to obliterative vasculopathy with prominent vascular proliferation, vulnerability to which is restricted to the striatum.

The McLeod syndrome without acanthocytes

A 45-year-old man developed chorea, behavioural changes, moderate amyotrophy and polyneuropathy. Hypertrophic cardiomyopathy and increased serum lactate dehydrogenase and creatine kinase (CK) were found. Acanthocytes were not detected. The absence of XK protein and faintly expressed Kell antigens on erythrocytes were found. Genetic test revealed a R133X mutation of the XK gene, confirming the McLeod syndrome. After 7 years he suddenly developed delirium followed by severe hypoglycaemia, hyperthermia, rhabdomyolysis, hepatic and renal failure. Malignant arrhythmia caused death.

Functional characterization of a novel mutation in TITF-1 in a patient with benign hereditary chorea

Benign hereditary chorea (BHC) is an autosomal dominant disorder of early onset characterised by non progressive choreic movements with normal cognitive function occasionally associated with hypothyroidism and respiratory problems. Numerous pieces of evidence link BHC with TITF-1/NKX2.1 gene mutations. We studied a patient with a familial benign hereditary chorea and normal thyroid and respiratory function. Sequence analysis of TITF-1 revealed the presence of a heterozygous C>T substitution at nucleotide 532, predicted to change an arginine (CGA) with a stop codon (TGA) at position 178 (R178X). A functional analysis shows that the mutated TTF-1 is not binding DNA, nor activating the canonical thyroid target gene promoter or interfering with the ability of wild type TTF-1 to activate transcription. In addition, the mutated protein is predominantly cytoplasmic, rather than nuclear as in the case of the wild type TTF-1. Thus, we have identified a new mutation in the TTF-1 coding gene in a patient with benign hereditary chorea. The results show that the mutation leads to a haploinsufficiency of TITF-1 and opens the question of genotype/phenotype correlation.

Tubulin is a neuronal target of autoantibodies in Sydenham's chorea

Sydenham's chorea is a CNS disorder and sequela of group A streptococcal infection where deposition of Abs in brain may result in movement and neuropsychiatric abnormalities. We studied human mAbs 24.3.1, 31.1.1, and 37.2.1 derived from chorea and selected for cross-reactivity with group A streptococci and brain Ags. Our novel findings reveal that Sydenham's chorea mAbs target a 55-kDa brain protein with an N-terminal amino acid sequence of MREIVHLQ corresponding to beta-tubulin. Chorea mAb specificity for purified brain tubulin was confirmed in ELISA and Western immunoblot, and significant levels of anti-tubulin IgG were found in acute chorea sera and cerebrospinal fluid. Lysoganglioside G(M1) inhibited binding of chorea mAbs to tubulin and mAb reactivity with human caudate and putamen brain sections was blocked by anti-tubulin mAb. The chorea mAbs labeled both intra- and extracellular Ags of a neuronal cell line providing evidence suggesting mimicry between intracellular brain protein tubulin and extracellular lysoganglioside. In addition, chorea mAb 24.3.1 and acute chorea sera induced calcium/calmodulin-dependent protein kinase II activity in human neuronal cells. Nucleotide sequence analysis of the chorea mAb V(H) genes revealed that mAb 24.3.1 V(H) gene was encoded by the V(H)1 germline gene family which encodes other anti-ganglioside V(H) genes associated with motor neuropathies. mAb recognition of tubulin and the neuronal cell surface with initiation of cell signaling and dopamine release supports an emerging theme in autoimmunity whereby cross-reactive or polyreactive autoantibodies against intracellular Ags recognize cell surface epitopes potentially leading to disease.

Genotype-phenotype correlation of paroxysmal nonkinesigenic dyskinesia

BACKGROUND

Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare disorder characterized by episodic hyperkinetic movement attacks. We have recently identified mutations in the MR-1 gene causing familial PNKD.

METHODS

We reviewed the clinical features of 14 kindreds with familial dyskinesia that was not clearly induced by movement or during sleep. Of these 14 kindreds, 8 had MR-1 mutations and 6 did not.

RESULTS

Patients with PNKD with MR-1 mutations had their attack onset in youth (infancy and early childhood). Typical attacks consisted of a mixture of chorea and dystonia in the limbs, face, and trunk, and typical attack duration lasted from 10 minutes to 1 hour. Caffeine, alcohol, and emotional stress were prominent precipitants. Attacks had a favorable response to benzodiazepines, such as clonazepam and diazepam. Attacks in families without MR-1 mutations were more variable in their age at onset, precipitants, clinical features, and response to medications. Several were induced by persistent exercise.

CONCLUSIONS

Paroxysmal nonkinesigenic dyskinesia (PNKD) should be strictly defined based on age at onset and ability to precipitate attacks with caffeine and alcohol. Patients with this clinical presentation (which is similar to the phenotype initially reported by Mount and Reback) are likely to harbor myofibrillogenesis regulator 1 (MR-1) gene mutations. Other "PNKD-like" families exist, but atypical features suggests that these subjects are clinically distinct from PNKD and do not have MR-1 mutations. Some may represent paroxysmal exertional dyskinesia.

Clinical features and natural history of neuroferritinopathy caused by the FTL1 460InsA mutation

Neuroferritinopathy is a progressive potentially treatable adult-onset movement disorder caused by mutations in the ferritin light chain gene (FTL1). Features overlap with common extrapyramidal disorders: idiopathic torsion dystonia, idiopathic Parkinson's disease and Huntington's disease, but the phenotype and natural history have not been defined. We studied a genetically homogeneous group of 41 subjects with the 460InsA mutation in FTL1, documenting the presentation, clinical course, biochemistry and neuroimaging. The mean age of onset was 39.4 years (SD = 13.3, range 13-63), beginning with chorea in 50%, focal lower limb dystonia in 42.5% and parkinsonism in 7.5%. The majority reported a family history of a movement disorder often misdiagnosed as Huntington's disease. The disease progressed relentlessly, becoming generalized over a 5-10 year period, eventually leading to aphonia, dysphagia and severe motor disability with subcortical/frontal cognitive dysfunction as a late feature. A characteristic action-specific facial dystonia was common (65%), and in 63% there was asymmetry throughout the disease course. Serum ferritin levels were low in the majority of males and post-menopausal females, but within normal limits for pre-menopausal females. MR brain imaging was abnormal on all affected individuals and one presymptomatic carrier. In conclusion, isolated parkinsonism is unusual in neuroferritinopathy, and unlike Huntington's disease, cognitive changes are absent or subtle in the early stages. Depressed serum ferritin is common and provides a useful screening test in routine practice, and gradient echo brain MRI will identify all symptomatic cases.

In vivo distribution and localization of chorein

Chorea-acanthocytosis (ChAc) is a hereditary neurodegenerative disorder caused by loss of function mutations in the VPS13A gene encoding chorein. In this study, we produced an antibody against chorein and examined its protein-level expression and localization in mouse. Immunoblot analysis revealed that chorein was expressed in a gene dose-dependent manner in the VPS13A deletion-mice that we recently developed, which confirms the sensitivity of the antibody. Chorein was highly expressed in testis, kidney, spleen, and brain, and was expressed ubiquitously in various brain regions. Subcellular analysis of the brain showed high levels of chorein in microsomal and synaptosomal fractions. Immunohistochemically, chorein-like immunoreactivity was ubiquitously observed in the brain in the neuronal perinuclear region, cytoplasm and fibers. In testis and kidney, clear cell-specific patterns of chorein-like immunoreactivity were detected. Our findings provide basic information on chorein in vivo and may contribute to taking the first step toward understanding molecular pathogenesis of ChAc.

Cerebral metabolic alterations in McLeod syndrome

The X-linked McLeod neuroacanthocytosis syndrome is a multisystem disorder with central nervous system manifestations resembling Huntington's disease. We examined 5 McLeod patients and 5 asymptomatic heterozygous females with fast multiple spin-echo spectroscopic imaging. Three patients with pronounced psychiatric or cognitive manifestations had pathological N-acetyl aspartate/(creatine + choline) ratios in frontal, temporal, and insular areas, with an individual pattern. Two patients with a severe choreatic movement disorder had unilateral thalamic alterations. One patient with moderate movement disorder and personality disorder had bilateral occipital alterations. One female heterozygote had unilateral insular metabolic alterations, possibly indicating subclinical cerebral involvement. Although the prominent psychiatric and cognitive manifestations in McLeod patients suggest significant and widespread cortical abnormalities, previous neuroradiological and histopathological data had not revealed definite extrastriatal pathology. Our findings demonstrating metabolic abnormalities in different brain regions of McLeod patients might either reflect neuronal dysfunction due to impaired basal ganglia-thalamo-cortical circuits or subtle structural alterations in the particular cerebral areas.

Brain magnetic resonance spectroscopy in Sydenham's chorea and ADHD

This report presents clinical, laboratory, and neuroimaging findings in a 7-year-old male with Sydenham's chorea associated with attention-deficit hyperactivity disorder. Western immunoblotting revealed serum anti-human basal ganglia tissue antibodies. Magnetic resonance imaging results were normal. Proton magnetic resonance spectroscopic imaging disclosed increased choline/creatine ratio in basal ganglia, frontal, and parieto-occipital areas, and decreased N-acetyl aspartate/creatine ratio in both basal ganglia and frontal areas. Moreover magnetic resonance spectroscopy revealed a peak between 3.6-4.2 ppm of unclear significance. The findings of this study are compared with the previous magnetic resonance spectroscopic studies reported on Sydenham's chorea and attention-deficit hyperactivity disorder. Magnetic spectroscopic imaging suggests an autoimmune basal ganglia damage in the pathogenesis of Sydenham's chorea and fronto-striatal impairment in attention-deficit hyperactivity disorder. In the present case, the previous history of an attention-deficit hyperactivity disorder suggests that this neurobehavioral disorder could be a risk factor for Sydenham's chorea in children with rheumatic fever.

The platelet maximum number of A2A-receptor binding sites (Bmax) linearly correlates with age at onset and CAG repeat expansion in Huntington's disease patients with predominant chorea

Huntington's disease (HD) is caused by an expanded CAG mutation and may show a heterogeneous clinical presentation. To date, although the age at onset mostly depends on the expanded CAG repeat number, no validated easy-to-test biomarkers exist either for following up patients progression rate or for exactly predicting age at onset (defined as the time when motor clinical manifestations first became noticeable). We tested the function of A(2A) receptor, strongly expressed in the brain striatum and peripheral cells, in patients' blood platelets and confirmed a maximum number of binding sites (B(max)) higher than in controls (216 +/- 9 versus 137 +/- 7; p=0.0001). We found a linear correlation between the receptor B(max) and the expanded CAG repeat number (n=52, r(2)=0.19, p=0.0011). When we selected the patients according to their clinical presentation (according to the predominating motor manifestations) and plotted the receptor B(max) against patients' age at onset, we found a significant linear correlation only when considering those subjects with chorea predominant on all other motor symptoms (n=26, r(2)=0.39, p=0.0007). Because the typical chorea may depend on early dysfunction of the striatum in HD, peripheral A(2A) amplification in blood platelets might reflect a central dysfunction in this part of the brain. Further studies on a larger sample size should confirm whether the analysis of A(2A)-receptor binding in patients' blood could be a useful clinical marker according to the patients' phenotype.

Presence of Alanine-to-Valine Substitutions in Myofibrillogenesis Regulator 1 in Paroxysmal Nonkinesigenic Dyskinesia

BACKGROUND

Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare disorder characterized by attacks of involuntary movements brought on by stress, alcohol, or caffeine, but not by movement. An autosomal dominant form of this disorder was mapped to chromosome 2q33-36, and different missense mutations in exon 1 of the myofibrillogenesis regulator 1 (MR1) gene were identified recently in 2 kindreds.

OBJECTIVES

To describe studies on a new pedigree with PNKD, to explore the possibility of locus heterogeneity, and to further delineate the spectrum of mutations in MR1 in 2 families with PNKD.

DESIGN, SETTING, AND PATIENTS

All 10 exons of MR1 were sequenced in DNA from members of 2 pedigrees with autosomal dominant PNKD.

RESULTS

Different missense mutations in exon 1 of MR1 that cosegregate with disease were identified in each multiplex family. These single-nucleotide mutations predicted substitution of valine for alanine in residue 7 in one family and residue 9 in the other. The same mutations were found in the only 2 families previously published. Family history and haplotype analysis make it unlikely that the families with the same mutations are related.

CONCLUSIONS

The function of MR1 is unknown, but the 2 mutations identified in the 4 families with PNKD studied to date are predicted to disrupt the amino terminal alpha-helix suggesting that this region of the gene is critical for proper gene function under stressful conditions. Study of additional families will be important to determine whether analysis of a single exon (MR1 exon 1) is sufficient for genetic testing purposes.

A gene-targeted mouse model for chorea-acanthocytosis

Chorea-acanthocytosis (CHAC) is a hereditary neurodegenerative disorder with autosomal recessive transmission, in which selective degeneration of striatum has been reported in brain pathology. Clinically, CHAC shows Huntington's disease-like neuropsychiatric symptoms and red blood cell acanthocytosis. Recently, we identified the gene, CHAC, encoding a novel protein, chorein, in which a deletion mutation was found in Japanese families with CHAC. In the present study, we have identified the mouse CHAC cDNA sequence and the exon-intron structures of the gene and produced a CHAC model mouse introducing no. 60-61 exon deletion corresponding to a human disease mutation by a gene-targeting technique. The mice began to show acanthocytosis and motor disturbance in old age. In behavioral observations, locomotor activity was significantly decreased and the contact time at social interaction test was decreased significantly in the model mice. In the brain pathology, many apoptotic cells were observed in the striatum of the mutant mice. In neurochemical determinations, the dopamine metabolite, homovanillic acid, concentration decreased significantly in the portion including the midbrain of the mutant mice. These findings are consistent with the human results reported elsewhere and indicate that the CHAC model mice showed a mild phenotype with late adult onset. The CHAC model mouse therefore provides a good model system to study the human disease.

Brain MR spectroscopy in children with a history of rheumatic fever with a special emphasis on neuropsychiatric complications

PURPOSE

To investigate whether there are metabolite changes in basal ganglia of children with complete healing of rheumatic fever (RF), history of Syndenham chorea (SC) and obsessive compulsive-tic disorder (OCTD) developed after RF when compared with healthy controls and each other.

MATERIAL AND METHODS

A total of 49 children with history of RF and 31 healthy controls were included into the study. All patients and control group underwent a detailed neuropsychiatric evaluation. Children with the history of RF were classified into three groups as; group 1: with history of RF without neuropsychiatric complications (NCRF), group 2: only with history of SC (HSC), group 3: with HSC and OCTD (OCTD). After MR imaging, single voxel MR spectroscopy was performed in all subjects. Voxels (15 x 15 x 15 mm) were placed in basal ganglia. N-acetyl aspartate (NAA)/creatin (Cr), and choline (Cho)/Cr ratios were calculated.

RESULTS

OCTD were detected in 13 children with HSC. NAA/Cr ratio was found to be decreased in these children when compared with NCRF (n:29), HSC without OCTD (n:7) and control groups (n:31). No significant difference was found in metabolite ratios of children with HSC without OCTD when compared with NCRF and control groups. There were no significant differences in Cho/Cr ratio between patient and control groups.

CONCLUSION

Although MR imaging findings was normal, MR spectroscopy findings (decreased NAA/Cr ratio) in our study support the neuronal loss in basal ganglia of children with OCTD and could indicate the development of permanent damage.

Alterations of striatal neurons in benign hereditary chorea

Benign hereditary chorea (BHC) recently has been associated with mutations in TITF-1 gene, although a pathological study of an individual with BHC and a TITF-1 mutation revealed no significant gross or microscopic abnormalities using standard methods. Immunohistochemical staining of striatal tissue from a BHC-affected postmortem brain was performed using antibodies against neurotransmitters of interneurons whose tangential migration is mediated by TITF-1. There was a loss of most TITF-1-mediated striatal interneurons in the BHC specimen compared to four matched control brains.

Adult-onset chorea and mitochondrial cytopathy

We report on 2 adult patients presenting with choreic movements as the main clinical feature of mitochondrial cytopathy. One patient exhibited a sensory neuronopathy and ophthalmoplegia. The other had ptosis, a proximal myopathy, and a sensory neuropathy. The diagnosis of mitochondrial cytopathy was established by the presence of ragged red fibers, cytochrome C oxydase-negative fibers, and a defect of the complex IV of the respiratory chain in muscle biopsy. No mutations in mitochondrial DNA were detected. The choreic movements observed in juvenile forms of mitochondrial cytopathy are rarely observed in adults. Although striatal vulnerability is commonly reported in patients with mitochondrial disorders, the mechanism by which the mitochondrial dysfunction leads to chorea is not known.

The gene for paroxysmal non-kinesigenic dyskinesia encodes an enzyme in a stress response pathway

Paroxysmal non-kinesigenic dyskinesia (PNKD) is characterized by spontaneous hyperkinetic attacks that are precipitated by alcohol, coffee, stress and fatigue. We report mutations in the myofibrillogenesis regulator 1 (MR-1) gene causing PNKD in 50 individuals from eight families. The mutations cause changes (Ala to Val) in the N-terminal region of two MR-1 isoforms. The MR-1L isoform is specifically expressed in brain and is localized to the cell membrane while the MR-1S isoform is ubiquitously expressed and shows diffuse cytoplasmic and nuclear localization. Bioinformatic analysis reveals that the MR-1 gene is homologous to the hydroxyacylglutathione hydrolase (HAGH) gene. HAGH functions in a pathway to detoxify methylglyoxal, a compound present in coffee and alcoholic beverages and produced as a by-product of oxidative stress. Our results suggest a mechanism whereby alcohol, coffee and stress may act as precipitants of attacks in PNKD. Stress response pathways will be important areas for elucidation of episodic disease genetics where stress is a common precipitant of many common disorders like epilepsy, migraine and cardiac arrhythmias.

Striatal increase of extracellular dopamine levels during dystonic episodes in a genetic model of paroxysmal dyskinesia

In vivo microdialysis was used to examine the levels of dopamine, serotonin, and their metabolites dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in the striatum of dt(sz) mutant hamsters, an animal model of paroxysmal dyskinesia, in which stress can precipitate dystonic episodes. Measurements were made under three different conditions in each animal: (1) at baseline in the absence of abnormal involuntary movements, (2) during an episode of paroxysmal dystonia precipitated by handling, and (3) during the recovery (postdystonic) period. In comparison to nondystonic control hamsters, which were treated in the same manner as dystonic animals, no changes could be detected under basal conditions, although the levels of DOPAC and HVA tended to be higher in mutant hamsters. Significantly elevated striatal levels of dopamine and DOPAC became evident during the period of stress-induced dystonic attacks in mutant hamsters. During dystonic episodes, dopamine levels were approximately 6.5-fold higher (followed by a 2.5-fold increase of DOPAC) in dt(sz) hamsters than in normal controls. Before the disappearance of dystonia, the levels of dopamine returned to basal concentrations in mutant hamsters. Consistent with previous pharmacologic findings, paroxysmal dystonia in mutant hamsters is associated with temporary increases of extracellular dopamine levels in the striatum.

Chorea-acanthocytosis associated with tourettism

We report on a case of Chorea-acanthocytosis (ChAc) in association with Tourettism that consisted of motor and vocal tics, attention deficit-hyperactivity disorder, and obsessive-compulsive disorder in addition to the typical symptoms of ChAc. The subject was compared with his elder sister who had the same disease but milder clinical profile and neuroradiological findings. The [(18)F]-2-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) findings did not explain the differences in symptomatology between the patient and his sister, although they may have correlated with severity.

Polyamines in a genetic animal model of paroxysmal dyskinesia

Previous studies suggested that glutamatergic overactivity contributes to the manifestation of dystonia in the dt(sz) mutant hamster, a model of idiopathic paroxysmal dyskinesia in which dystonic episodes occur in response to mild stress. Therefore, the role of polyamines, known as positive modulators of NMDA receptors, was examined in the present study. The levels of polyamines (putrescine, spermidine, spermine) were determined in forebrain, cerebellum and brainstem in dt(sz) hamsters at an age of most marked expression of dystonia (32 days) and in age-matched non-dystonic control hamsters. Spermine was found to be significantly increased in the forebrain (35%) of dystonic animals, while spermidine was unaltered in dystonic brains and only a moderate increase in putrescine (12%) was detected in the cerebellum of dt(sz) mutants. In view of enhanced spermine levels, the effect of the putative polyamine receptor antagonist ifenprodil on the severity of dystonia was examined in dystonic hamsters. Ifenprodil (5-40 mg/kg i.p.) failed to exert a beneficial effect, but even aggravated dystonia in the dt(sz) mutant at higher doses. These data together with previous pharmacological findings in mutant hamsters do not completely exclude a pathophysiological role of enhanced polyamine levels but suggest that overstimulation of NMDA receptors which contain NR2B subunits by enhanced spermine levels is not involved in the dystonic syndrome.

Mimicry and autoantibody-mediated neuronal cell signaling in Sydenham chorea

Streptococcus pyogenes-induced acute rheumatic fever (ARF) is one of the best examples of postinfectious autoimmunity due to molecular mimicry between host and pathogen. Sydenham chorea is the major neurological manifestation of ARF but its pathogenesis has remained elusive, with no candidate autoantigen or mechanism of pathogenesis described. Chorea monoclonal antibodies showed specificity for mammalian lysoganglioside and N-acetyl-beta-D-glucosamine (GlcNAc), the dominant epitope of the group A streptococcal (GAS) carbohydrate. Chorea antibodies targeted the surface of human neuronal cells, with specific induction of calcium/calmodulin-dependent protein (CaM) kinase II activity by monoclonal antibody 24.3.1 and sera from active chorea. Convalescent sera and sera from other streptococcal diseases in the absence of chorea did not activate the kinase. The new evidence implicates antibody-mediated neuronal cell signaling in the immunopathogenesis of Sydenham chorea and will lead to a better understanding of other antibody-mediated neurological disorders.

Decreased gene expression of calretinin and ryanodine receptor type 1 in tottering mice

Tottering mice are a spontaneously occurring animal model of human absence epilepsy. They carry a mutation in the P/Q-type calcium channel alpha1A subunit gene which is highly expressed by cerebellar Purkinje cells. In this study, we investigated the role of calretinin and ryanodine receptor type 1 (RyR1) gene expression in the cerebellum of tottering mice. Cerebellar tissue specimens from four experimental groups were processed for in situ hybridization histochemistry (ISHH): (1) wild-type (+/+); (2) heterozygous (tg/+) and two homozygous groups; either (3) without occurrence of an episode of paroxysmal dyskinesia (tg/tg-N); or (4) after an episode of paroxysmal dyskinesia (tg/tg-P) that lasted about 45 min on average. Quantitative analysis showed a statistically significant decrease (p = 0.0001, ANOVA) of calretinin gene expression at the level of the simple lobule of the cerebellum in both homozygous groups compared to the wild-type and heterozygous groups. RyR1 was decreased in the flocculus of the cerebellum in both the tg/tg-N and tg/tg-P groups compared to wild type (p = 0.0174, ANOVA). These results suggest that calretinin gene expression, as well as other genes involved in regulation of calcium homeostasis, such as RyR1, may play a role in the biochemical functional alterations present in tottering mice.

Mutation analysis of the sodium/hydrogen exchanger gene (NHE5) in familial paroxysmal kinesigenic dyskinesia

Familial Paroxysmal Kinesigenic Dyskinesia (PKD) is an autosomal dominant condition characterized by attacks of dystonia or chorea triggered by sudden movements. Recently two separate loci for PKD, Episodic Kinesigenic Dyskinesia 1 (EKD1) and Episodic Kinesigenic Dyskinesia 2 (EKD2), have been mapped to chromosome 16 but the causative genes have not been identified. The Na(+)/H(+) exchanger gene (NHE5) involved in regulating intracellular pH lies in the EKD2 region. The coding region of the NHE5 gene in familial PKD was sequenced. We did not identify any mutations in the exons, intron/exon boundaries or the 5' and 3'UTR. This excludes mutations in the coding region of the NHE5 gene as a cause for familial PKD, but does not rule out a possible role of sequence variants in introns or regulatory regions.

Ataxia and paroxysmal dyskinesia in mice lacking axonally transported FGF14

Fibroblast growth factor 14 (FGF14) belongs to a distinct subclass of FGFs that is expressed in the developing and adult CNS. We disrupted the Fgf14 gene and introduced an Fgf14(N-beta-Gal) allele that abolished Fgf14 expression and generated a fusion protein (FGF14N-beta-gal) containing the first exon of FGF14 and beta-galactosidase. Fgf14-deficient mice were viable, fertile, and anatomically normal, but developed ataxia and a paroxysmal hyperkinetic movement disorder. Neuropharmacological studies showed that Fgf14-deficient mice have reduced responses to dopamine agonists. The paroxysmal hyperkinetic movement disorder phenocopies a form of dystonia, a disease often associated with dysfunction of the putamen. Strikingly, the FGF14N-beta-gal chimeric protein was efficiently transported into neuronal processes in the basal ganglia and cerebellum. Together, these studies identify a novel function for FGF14 in neuronal signaling and implicate FGF14 in axonal trafficking and synaptosomal function.

In vivo proton MR spectroscopy of chorea-ballismus in diabetes mellitus

The most common cause of chorea-ballismus (CB) is a vascular lesion; it is also associated with nonketotic hyperglycaemia in diabetes mellitus (DM) and may be the first manifestation of this disorder. We describe the CT, MRI and proton MR spectroscopy (1H-MRS) of CB in eight patients. Six had hemichorea-hemiballismus (HC-HB) and two bilateral CB. Single-voxel (SV) 1H-MRS was performed using point-resolved spectroscopy (PRESS). Voxels were positioned in the basal ganglia of the patients and control subjects. PRESS was also used to obtain spectroscopic imaging (1H-MRSI) of the slice of interest in two patients. CT showed a slightly dense striatum in all the patients with CB, and T1-weighted images revealed high signal. The CB correlated well with the neuroimaging findings. SV 1H-MRS showed the mean (+/- SD) N-acetylaspartate (NAA)/ creatine (Cr) ratio to be 1.45 +/- 0.19 in HC-HB and 1.82 +/- 0.06 on the opposite normal side (P = 0.01). The choline (Cho)/ Cr ratio was 1.3 +/- 0.12 in HC-HB and 1.11 +/- 0.13 on the opposite normal side (P = 0.005). A lactate peak was seen in seven patients. The NAA/Cr ratio was 1.44 +/- 0.15 in bilateral CB and 1.74 +/- 0.16 in the controls (P = 0.017); the Cho/Cr ratios were 1.36 +/- 0.1 and 1.19 +/- 0.07 (P = 0.015). The low NAA/Cr suggests neuronal loss or damage and the high Cho/Cr probably indicates gliosis. The presence of lactate may suggest mild ischaemia due to acute vascular events during hyperglycaemia and underlying chronic focal cerebrovascular diseases in DM.

Reduction of striatal glucose metabolism in McLeod choreoacanthocytosis

McLeod syndrome is a distinct form of neuroacanthocytosis. Its defining feature is the depression of erythrocyte Kell antigens. The underlying X chromosomal mutations cause a dysfunction of an erythrocyte membrane protein Kx. A choreatic movement disorder with caudate atrophy in CT and MRI has been reported in McLeod syndrome later in the course of the disease. Positron emission tomography with 18F-deoxyglucose (FDG) was performed in two unrelated affected men. In the older patient, progressive chorea was seen from the 5th decade. In the second patient there were no signs of a movement disorder at the age of 28. Positron emission tomography disclosed a reduction of the striatal FDG uptake in both patients, with accentuation in patient 1. Frontal lobe metabolism was not affected. Basal ganglia dysfunction with early impairment of striatal glucose metabolism thus seems obligatory for McLeod syndrome, as found in other forms of chorea with or without acanthocytosis.

(+)-alpha-[11C]Dihydrotetrabenazine PET imaging in familial paroxysmal dystonic choreoathetosis

Clinical observations suggest a disturbance of striatal dopaminergic function in familial paroxysmal dystonic choreoathetosis (PDC). The authors used PET with [11C]dihydrotetrabenazine (DTBZ) to study striatal dopaminergic innervation in PDC. The results did not reveal abnormal DTBZ binding potential in PDC striatum. This suggests that dopaminergic abnormalities, if present, may be due to altered regulation of dopamine release or to postsynaptic mechanisms, rather than to an altered density of nigrostriatal innervation.

Cerebral hypoperfusion and hypometabolism with altered striatal signal intensity in chorea-acanthocytosis: a combined PET and MRI study

We studied cerebral perfusion and oxygen metabolism in three patients with chorea-acanthocytosis using positron-emission tomography and oxygen-15 labeled O2 and CO2. High-field magnetic resonance imaging also was performed. Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) were significantly reduced in the caudate and putamen when compared with seven control subjects. Mild but significant reductions of rCBF (lower than the normal control values -2 SD) were found in the bilateral frontal, left temporal and parietal, and bilateral thalamic areas; rCMRO2 was reduced in the bilateral frontal and left temporal areas. Magnetic resonance imaging showed increased signal intensity accompanied by scattered bright spots in the caudate head and putamen on T2-weighted images; decreased signal intensity was shown at these sites on T1-weighted images. These findings were not observed in 10 neurologically normal volunteers and are rare in the common hyperkinetic form of Huntington's disease. Reduced cerebral perfusion and oxygen metabolism seem to be related to the intellectual and personality changes that occur in chorea-acanthocytosis. Combined positron-emission tomography and magnetic resonance imaging studies may improve diagnostic accuracy in patients with chorea-acanthocytosis and related disorders.

Reversible chorea in primary antiphospholipid syndrome

A 20-year-old woman with acute chorea induced by primary antiphospholipid syndrome was studied by using fluorodeoxyglucose and positron emission tomography (PET). PET sessions were conducted during an episode of severe chorea and after recovery. The symptoms predominantly affected the right side of her face and body, and PET demonstrated a corresponding increase in lentiform and caudate nucleus metabolism prevailing on the left side. After recovery, PET showed normal values in the regions previously studied. This study adds further evidence to support the theory that acute choreas are somehow the result of striatal hypermetabolism.

Increased membrane protein phosphorylation and anion transport activity in chorea-acanthocytosis

BACKGROUND AND OBJECTIVE

Chorea-acanthocytosis is a disorder characterized by neuronal degeneration and the presence of acanthocytic erythrocytes on blood smear. The abnormal function and structure of the membrane protein band 3 are considered to be of pathogenetic relevance in determining the erythrocyte defect.

METHODS

In a clinically evident case of chorea-acanthocytosis, the following parameters were investigated: membrane cholesterol and fatty acid composition, sulphate influx (as a measure of the anion transport activity), membrane protein phosphorylation, membrane casein and tyrosin-kinase activities; moreover, the promoter and all exons of the EPB3 gene were screened for possible mutations by single strand conformational polymorphism (SSCP) study.

RESULTS

The sulphate influx, the Ser/Thr phosphorylation level, and the membrane casein-kinase activity were increased in chorea-acanthocytosis compared with normal controls. In the intact vanadate-treated 32P-labelled erythrocytes, Tyr-phosphorylation of the cytoplasmic domain of band 3, as well as the poly(Glu, Tyr) kinase activity in the membranes, were enhanced in the patient's sample. Apparent molecular weight and concentration of band 3 on SDS/PAGE analysis, membrane fatty acid composition and cholesterol/phospholipid molar ratio were normal and the SSCP study of EPB3 exons did not show any abnormal polymorphisms.

INTERPRETATIONS AND CONCLUSIONS

An abnormal degree of phosphorylation of membrane proteins, in particular of band 2 (beta-subunit) and band 3, may contribute in determining both change of cell shape and increased anion transport in chorea-acanthocytosis.

Non-ketotic hyperglycaemic chorea: a SPECT study

OBJECTIVE

To study regional blood flow of the striatum in non-ketotic hyperglycaemic choreic patients.

METHODS

Brain SPECT was performed with intravenous injection of 20 mCi 99mTc hexamethylpropylene amineoxime in six non-ketotic hyperglycaemic choreic patients and 10 age matched patients with a similar level of hyperglycaemia without chorea as a control. The focal perfusion defects were analysed by visual interpretation and semiquantitative determination with reference to homolateral occipital blood flow.

RESULTS

The measured blood flow of striatum on the contralateral side of chorea was significantly decreased.

CONCLUSIONS

Hypometabolism of the striatum is seen not only in Huntington's disease, but also in non-ketotic hyperglycaemic chorea. Hypofunction of the striatum is a possible common pathogenesis in the development of contralateral chorea in different diseases. Furthermore, the sensitivity and reliability of SPECT is as good as PET in assessing choreic patients.

Striatal D1 and D2 receptor binding in patients with Huntington's disease and other choreas. A PET study

We have used PET to study striatal D1 and D2 receptor binding in 10 patients with either the choreic or akinetic-rigid variants of Huntington's disease and in three patients with other causes of chorea. Background rigidity and bradykinesia in choreic patients were scored with a four-point scale. PET studies showed a severe and parallel reduction of both striatal D1 and D2 receptor binding in Huntington's disease patients irrespective of their predominant phenotype (mean reduction 60%). Huntington's disease patients with rigidity showed more pronounced reduction of striatal D1 and D2 binding compared with those without rigidity. A case of chorea associated with systemic lupus erythematosus had normal D2 binding. These results suggest that the presence of chorea per se may not be determined by alterations in striatal dopamine receptor binding, but that rigidity in Huntington's disease is associated with severe striatal D1 and D2 receptor loss.

SPECT imaging of dopamine receptors with [123I]epidepride: characterization of uptake in the human brain

[123I]Epidepride is a new ligand for single photon emission computerized tomography (SPECT) that specifically labels D2-like dopamine receptors with very high affinity. Here, we report on the regional kinetic uptake of [123I]epidepride in the brain of 4 normal volunteers and 3 patients with choreatic movement disorders. In healthy subjects striatal activity peaked at 2.5 hours after injection of the tracer and decreased slowly thereafter. There were no significant differences between left and right brain hemispheres. Activity above background was also measurable in areas corresponding to the thalamus, temporal cortex and frontal cortex. The striatal to cerebellar ratio was about 14 after 2.5 hours and this ratio steadily increased with time. The striatal to cerebellar ratio was clearly reduced in all 3 patients with choreatic movement disorders (from about 14 in control subjects after 2.5 hours to about 7 in choreatic patients). [123I]Epidepride may be a useful SPECT ligand for studying D2 receptors in the living human brain because of its high target to background ratio, its high affinity and the possibility to investigate extrastriatal D2 receptors.

Alternating hemichorea in primary antiphospholipid syndrome: evidence for contralateral striatal hypermetabolism

We used 18F-fluorodeoxyglucose and PET to study a 23-year-old woman with alternating hemichorea and primary antiphospholipid syndrome. There were three PET studies: (1) during an episode of right hemichorea, (2) during an asymptomatic period 6 months later, and (3) during an episode of left hemichorea occurring 2 months after that. In each study, we calculated normalized regional glucose metabolism for the caudate and lentiform nuclei and compared these values with those calculated in 12 normal volunteer subjects (mean age, 35.3 +/- 9.0). The following results were obtained: (1) during right hemichorea, left lentiform metabolism was increased by 19% (> 3 SD); (2) during the asymptomatic period, right caudate metabolism was increased by 20% (> 3 SD), and right lentiform and left striatal metabolism were normal; and (3) during left hemichorea, right caudate and lentiform metabolism were both elevated by 33% (> 3 SD). During this episode, left caudate metabolism was elevated by 20% (> 2 SD); left lentiform metabolism was normal. These results suggest that hemichorea in primary antiphospholipid syndrome may be associated with contralateral striatal hypermetabolism that may also be present during asymptomatic periods.

Erythrocyte anion transporter and antibrain immunoreactivity in chorea-acanthocytosis. A contribution to etiology, genetics, and diagnosis

Novel structural and functional alterations in the erythrocyte anion transporter band 3 are described in one patient with definite, and in two patients with symptoms compatible with chorea-acanthocytosis, but without acanthocytes. Immunoblotting analysis shows increased fragmentation of band 3, and sulfate flux measurements indicate that anion transport activity is reduced in the erythrocytes of these patients. These changes are similar, but not identical to those observed during normal erythrocyte aging. In addition, distinct antibrain immunoreactivity was present in the plasma of these patients. A family study indicates that abnormal erythrocyte band 3 structure and function and antibrain immunoreactivity may be phenotypes of two independent, genetically determined factors, that are part of the heterogenic defect of chorea-acanthocytosis. The findings in the patients without acanthocytes indicate that the biochemical abnormalities may be related to a chorea-acanthocytosis-like, amyotrophic extrapyramidal movement disorder with axonal neuropathy. Measurement of erythrocyte sulfate transport and plasma antibrain immunoreactivity could be of use in establishing the diagnosis and further unravelling the genetic background of chorea-acanthocytosis and related syndromes.

Increased striatal glucose consumption in Sydenham's chorea

Positron emission tomography and 18F-fluorodeoxyglucose were used to measure the regional cerebral glucose consumption in a 15-year-old choreatic girl with classical Sydenham's chorea shortly after the onset of hyperkinetic movements and 5 months later after chorea had resolved and in a 74-year-old hemichoreatic woman with long-standing hyperkinesia as a residuum of Sydenham's chorea in adolescence. Whereas cerebellar, thalamic, and cortical glucose consumption was within normal limits in both patients, lentiform and caudate glucose consumption was significantly increased in both hemispheres of the 15-year-old patient and in the hemisphere contralateral to the chorea in the 74-year-old patient. In the younger patient, striatal glucose consumption returned to normal after her hyperkinesia had disappeared with antibiotic therapy. The observation of an increase in striatal glucose consumption in Sydenham's chorea, in contrast to the decrease of this variable encountered in the vast majority of other choreatic disorders, leads to questioning the pathophysiology of chorea in humans and suggests the use of emission tomographic measurement of variables related to cerebral energy metabolism for differential diagnosis in choreatic disorders.

Reversible striatal hypermetabolism in a case of Sydenham's chorea

We studied a 10-year-old girl with Sydenham's chorea (SC) using positron emission tomography (PET) with fluorodeoxyglucose (FDG). Choreic movements involved the head and the left side of her body. PET showed increased glucose metabolism in the right caudate nucleus and putamen. Three months after complete recovery, striatal glucose metabolism had returned to normal in the caudate nucleus. In the right putamen, glucose metabolism had decreased compared to that in the first study but remained elevated compared to that of normal young adults. We propose that the transient striatal hypermetabolism may have been due to increased afferent inputs to the striatum as a consequence of striatal or subthalamic nucleus dysfunction.

Cerebral glucose metabolism and striatal 18F-dopa uptake by PET in cases of chorea with or without dementia

Cerebral glucose metabolism was studied by positron emission tomography with [18F]fluorodeoxyglucose in 12 patients with chorea due to different underlying diseases. The striatal 18F-dopa uptake was also studied with 6-L-[18F]fluorodopa in 6 of them. Five of them were diagnosed as Huntington's disease two were as 'sporadic progressive chorea and dementia' with characteristic symptoms and signs of Huntington's disease but no family histories, two were as choreoacanthocytosis, and two had hemichorea caused by suspected vascular lesions in the contralateral striatum revealed by MRI. Caudate and putaminal glucose metabolism decreased in chorea compared to the controls. Hemichorea showed decreased glucose metabolism only in the contralateral striatum. Moreover the glucose metabolism decreased in demented each 7 patients in the frontal, temporal and parietal cortices as well as in the striatum. The caudate and putaminal 18F-dopa uptake in patients with chorea showed no difference with that in the controls. The pathogenetic mechanism of chorea may involve decreased glucose metabolism and normal presynaptic dopaminergic activity in the striatum, and that of the demented state in chorea may also involve an additional decrease of the glucose metabolism in the frontal, temporal and parietal cortices.

Regional cerebral glucose metabolism in clinical subtypes of cerebral palsy

Twenty-three children with 4 clinical subtypes of cerebral palsy were studied using 2-deoxy-2(18F)fluoro-D-glucose (FDG) and positron emission tomography (PET). Subtypes included spastic quadriparesis (N = 6), spastic diplegia (N = 4), infantile hemiplegia (N = 8), and choreoathetosis (N = 5). FDG-PET images were correlated with magnetic resonance imaging or computed tomography. Although the location of glucose metabolic abnormalities corresponded, in general, to abnormalities of brain structure demonstrated by structural imaging studies, the distribution of metabolic impairment almost invariably extended beyond the region of anatomic involvement. The following observations in specific subtypes of cerebral palsy were determined with FDG-PET: (1) In spastic diplegic patients, PET revealed focal areas of cortical hypometabolism in the absence of apparent structural abnormality; (2) A relatively normal pattern of cortical metabolism was observed in most patients with choreoathetoid cerebral palsy, despite marked hypometabolism in the thalamus and lenticular nuclei; and (3) In patients with infantile hemiplegia, FDG-PET disclosed symmetric cerebellar glucose metabolism with absence of crossed cerebellar hypometabolism (diaschisis). This finding is contrary to the typical persistence of crossed cerebellar diaschisis in adult patients with acquired cerebral lesions and suggests metabolic recovery due to developmental plasticity. The possibility that FDG-PET may be clinically useful in identifying the cerebral palsy patient with potential learning handicap and in the study of functional recovery or sparing following brain injury should be explored further.