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

Abstract

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.

Decreased Contralateral Putamen [¹²³I]FP-CIT SPECT Uptake in Hyperglycemic Hemichorea-Hemiballismus

“…To the best of our knowledge, this is the first report describing reduced presynaptic dopaminergic function predominant in the putamen in a patient with HCHB syndrome. In a recent work, in monozygotic twins with chorea-acanthocytosis, a reduction in DAT SPECT with ␤ -CIT was found [5] . In that paper, the most important DAT reduction was found contralateral to the most affected side by hyperkinetic movements and changes in the same region were also found by diffusion tensor imaging and FDG-PET [5] , confirming that the more pronounced clinical presentation could be the expression of more important putaminal changes [2] .…”

Reversible abnormal functional neuroimaging presentations in polycythemia vera with chorea

“…The first pattern, seen in patients with neuroacanthocytosis and chorea, shows diminution of FDG uptake in the basal ganglia with increased uptake in the frontal cortex contralateral to the choreiform side [12]. The reason for this phenomenon is uncertain, but it may be related to neuronal destruction and decreased chorein levels in the basal ganglia [12]. The increased cortical metabolism in neuroacanthocytosis has not been explained, but is speculated to be associated with the neuropsychiatric features in these patients [12].…”

“…b After treatment: there is increased and more symmetrical uptake of dopamine transporter in the bilateral striatum compared to ''before-treatment'' images Two patterns of FDG PET have been described in patients with chorea. The first pattern, seen in patients with neuroacanthocytosis and chorea, shows diminution of FDG uptake in the basal ganglia with increased uptake in the frontal cortex contralateral to the choreiform side [12]. The reason for this phenomenon is uncertain, but it may be related to neuronal destruction and decreased chorein levels in the basal ganglia [12].…”

“…The reason for this phenomenon is uncertain, but it may be related to neuronal destruction and decreased chorein levels in the basal ganglia [12]. The increased cortical metabolism in neuroacanthocytosis has not been explained, but is speculated to be associated with the neuropsychiatric features in these patients [12]. The second pattern involves increased activation of the bilateral insula and underactivity of the frontal areas in patients with Huntington's disease (HD) [18].…”

Reduction of Glucose Metabolism in Basal Ganglia Diagnosed With FDG-PET Scan

“…4 On the FDG-PET scan of the patient, no FDG uptake was observed in the caudate nucleus and putamen. [5][6][7] Thalamus activity showed normal distribution. Magnetic resonance imaging of the brain was normal and the electroencephalogramshowed normal epileptiform activity.…”