Regional brain glucose metabolism in neuroacanthocytosis

Functional neuroimaging and chorea: a systematic review

Chorea is a hyperkinetic movement disorder consisting of involuntary irregular, flowing movements of the trunk, neck or face. Although Huntington’s disease is the most common cause of chorea in adults, chorea can also result from many other neurodegenerative, metabolic, and autoimmune conditions. While the pathophysiology of these different conditions is quite variable, recent advances in functional imaging have enabled the development of new methods for analysis of brain activity and neuronal dysfunction. In this paper we review the growing body of functional imaging data that has been performed in chorea syndromes and identify particular trends, which can be used to better understand the underlying network changes within the basal ganglia. While it can be challenging to identify whether changes are primary, secondary, or compensatory, identification of these trends can ultimately be useful in diagnostic testing and treatment in many of the conditions that cause chorea.

Chorea-acanthocytosis in monozygotic twins: clinical findings and neuropathological changes as detected by diffusion tensor imaging, FDG-PET and 123I-β-CIT-SPECT

We report on two 33 years old monozygotic twins with chorea-acanthocytosis (ChAc) misdiagnosed as schizophrenia and Tourette syndrome, respectively. Although the patients shared several clinical similarities, there were also some clear differences: twin 1 presented initially with an acute episode of a paranoid schizophrenia, while twin 2 suffered from generalized epileptic seizures. In both twins, MRI demonstrated caudate nucleus atrophy and an increased apparent diffusion coefficient (ADC) in the striatum bilaterally with right sided predominance. (18)F-FDG PET showed bilaterally reduced glucose utilization in the striatum with clearly pronounced reduction on the right side compared to the left and in twin 1 compared to twin 2. Ratios of binding to striatal dopamine transporters (DAT) and serotonin transporters in the hypothalamus midbrain area as determined using (123)I-beta-CIT-SPECT fell within the normal ranges. However, in twin 1 a significant difference in binding to presynaptic DAT with marked reduction on the right hemisphere was observed. Right hemispheric accentuated changes measured by MRI, FDG-PET, and (123)I-beta-CITSPECT correspond to more severe hyperkinetic movements on the left part of the body in both twins. Different neuro-psychiatric features in this monocygotic twin pair suggest that not only genetic but also environmental factors contribute to the clinical symptomatology. Our findings suggest that the main neuropathological process in ChAc is located in the striatum, involving microstructural alterations, and disturbance of metabolism and dopaminergic neurotransmission.

Head of the caudate nucleus is most vulnerable in chorea-acanthocytosis: a voxel-based morphometry study

Chorea-acanthocytosis (ChAc; OMIM 200150) is a rare autosomal recessive disease with dysfunction of the erythrocyte membrane, presenting with acanthocytes and neurological manifestations characterized by progressive hyperkinesias (chorea, dystonia) and neuropsychological impairment. Damage to the basal ganglia was described previously in neuropathological and neuroimaging investigations. We analyzed high-resolution MRI of six ChAc patients with mutations in the VPS13A gene (median age, 37 years; mean time since clinical onset, 13 years) with respect to regional atrophy by use of the observer-independent technique of voxel-based morphometry in comparison to 15 age-matched healthy controls. Additionally, global brain atrophy was determined using the standardized brain parenchymal fraction (BPF) method. A robust regional reduction of gray matter density was observed in the head of the caudate nucleus bilaterally and was nearly symmetrical (P < 0.001, corrected for small volumes). No additional gray matter changes were found. In the BPF analysis, there was no significant global brain atrophy. The predilection of atrophy in the head of the caudate nucleus, as suggested by our results, argues for a particular vulnerability of this part of the striatum in ChAc and is in agreement with pronounced neuropsychological disturbances that are thought to rely on these regions.

Neuropsychologische Störungen bei einem monozygoten Zwillingspaar mit Chorea-Akanthozytose

Zusammenfassung: Chorea-Akanthozytose (ChAc) ist eine seltene, genetisch bedingte Erkrankung, welche durch charakteristische neurologische und psychiatrische Symptome gekennzeichnet ist. In der vorliegenden Fallbeschreibung wird ein männliches monozygotes Zwillingspaar vorgestellt, das aufgrund ähnlicher Kombinationen komplexer Bewegungsstörungen (choreatische und parkinsonähnliche Bewegungen), Dystonien und Vokalisationen sowie Verhaltensauffälligkeiten und kognitive Beeinträchtigungen als Tourette-Syndrom fehldiagnostiziert wurde. Eine ausführliche neuropsychologische Untersuchung deutete auf eine fronto-subkortikale Demenz, wobei einige Befunde zwischen den Brüdern diskrepant waren. Die unterschiedlichen Ergebnisse der neurologischen, neuropsychologischen und psychiatrischen Untersuchung lassen annehmen, dass neben genetischen auch nicht-genetische Faktoren die klinische Symptomatik der ChAc Patienten beeinflussen. Darüber hinaus verdeutlicht der Fallbericht, dass eine detaillierte neuropsychologische Untersuchung einen wesentlichen Beitrag zur Diagnosesicherung der ChAc leisten kann.

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.

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.

Functional imaging techniques in the diagnosis of non-Alzheimer dementias

Functional imaging (positron emission tomography -- PET, single photon emission tomography -- SPECT, magnetic resonance spectroscopy -- MRS) enables regional cerebral function to be assessed in vivo in dementias. There are three basic approaches to examining the patterns of cerebral function associated with specific disorders: First, abnormalities in resting levels of regional cerebral metabolism and blood flow can be examined. Second, patients can be asked to perform cognitive tasks with a view to demonstrating aberrations in their pattern of cerebral activation. Third, resting dysfunction of brain pharmacology can be revealed. The bulk of the research on non-Alzheimer dementias has been performed with PET and SPECT and this review will concentrate on these two modalities.

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.

Striatal glucose consumption in chorea-free subjects at risk of Huntington's disease

Controversial data have been reported with regard to the diagnostic value of the positron emission tomographic (PET) measurement of striatal glucose consumption (rCMRGlc) in chorea-free subjects at risk of Huntington's disease (HD). For further clarification of this issue we measured striatal and cerebellar rCMRGlc in 27 chorea-free subjects at risk of HD, 20 patients with manifest HD and 20 control subjects, using PET and 18F-fluorodeoxyglucose. In 6 of the at-risk subjects cerebellar ratios of striatal rCMRGlc were decreased below the corresponding 99% confidence limit determined in the controls. This indicates that the PET measurement of rCMRGlc may, indeed, be valuable in establishing the diagnosis of incipient HD in presymptomatic at-risk subjects.

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.

Presynaptic and postsynaptic striatal dopaminergic function in neuroacanthocytosis: a positron emission tomographic study

Using [18F]dopa, [11C]raclopride, C15O2, and positron emission tomography, we have assessed striatal dopamine storage capacity, dopamine D2-receptor integrity, and regional cerebral blood flow, respectively, of 6 patients with neuroacanthocytosis. The patients with neurocanthocytosis all had chorea and variable combinations of seizures, dementia, axonal neuropathy, and orolingual self-multiation. [18F]dopa positron emmission tomographic findings were compared with 30 normal controls and 16 patients with sporadic, L-dopa-responsive, Parkinson's disease. Caudate and anterior putamen [18F]dopa uptake were normal in patients with neuroacanthocytosis, but mean posterior putamen [18F]dopa uptake was reduced to 42% of normal, similar to that in patients with Parkinson's disease. In patients with neuroacanthocytosis, mean equilibrium caudate: cerebellum and putamen: cerebellum [11C]raclopride uptake ratios were reduced to 54% and 62% of normal, compatible with a 65% and 53% loss of caudate and putamen D2-receptor-binding sites, respectively. Striatal and frontal blood flow was also depressed. The severe loss of D2-receptor-bearing striatal neuron, with concomitant loss of dopaminergic projections from the nigra to the posterior putamen, is consistent with both chorea and extrapyramidal rigidity being features of patients with neuroacanthocytosis.