Browsing by Author "Fritsch, Rosemarie"

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    Functional Dysconnectivity in Ventral Striatocortical Systems in 22q11.2 Deletion Syndrome
    (OXFORD UNIV PRESS, 2021) Tepper, Angeles; Cuiza Vasquez Analia; Alliende, Luz María; Mena, Carlos; Ramirez Mahaluf, Juan Pablo; Iruretagoyena, Barbara; Ornstein, Claudia; Fritsch, Rosemarie; Nachar, Ruben; Gonzalez Valderrama, Alfonso; Undurraga, Juan; Pablo Cruz, Juan; Tejos, Cristian; Fornito, Alex; Repetto, Gabriela; Crossley, Nicolas
    22q11.2 deletion syndrome (22q11.2DS) is a genetic neurodevelopmental disorder that represents one of the greatest known risk factors for psychosis. Previous studies in psychotic subjects without the deletion have identified a dopaminergic dysfunction in striatal regions, and dysconnectivity of striatocortical systems, as an important mechanism in the emergence of psychosis. Here, we used resting-state functional MRI to examine striatocortical functional connectivity in 22q11.2DS patients. We used a 2 x 2 factorial design including 125 subjects (55 healthy controls, 28 22q11.2DS patients without a history of psychosis, 10 22q11.2DS patients with a history of psychosis, and 32 subjects with a history of psychosis without the deletion), allowing us to identify network effects related to the deletion and to the presence of psychosis. In line with previous results from psychotic patients without 22q11.2DS, we found that there was a dorsal to ventral gradient of hypo- to hyperstriatocortical connectivity related to psychosis across both patient groups. The 22q11.2DS was additionally associated with abnormal functional connectivity in ventral striatocortical networks, with no significant differences identified in the dorsal system. Abnormalities in the ventral striatocortical system observed in these individuals with high genetic risk to psychosis may thus reflect a marker of illness risk.
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    Prodromal manifestations of Parkinson’s disease in adults with 22q11.2 microdeletion syndrome
    (2022) Juri, Carlos; Chaná-Cuevas, Pedro; Kramer, Vasko; Fritsch, Rosemarie; Ornstein, Claudia; Cuiza, Analía; Hernández, Carlos; Villanueva, Katiuska; Cordova, Teresa; Mauro, Jorge; Ocampo, Adrián; Rebolledo-Jaramillo, Boris; Repetto, Gabriela M.
    22q11.2 microdeletion syndrome (22qDS) was recently identified as a risk factor for development of early-onset Parkinson´s disease (PD). The classical motor manifestations of this disease are preceded by early signs and symptoms of neurodegeneration. The progression of 22qDS-associated PD is unknown. We aimed to evaluate the presence of prodromal PD in a group of adults with 22qDS using the Movement Disorders Society (MDS) Criteria for Prodromal PD. Thirty-eight persons with 22qDS and 13 age-matched controls participated in the study, and their results were compared using the MannWhitney U test. Persons with 22qDS had lower scores on olfaction testing (p=7.42Ex10-5), higher scores on the COMPASS 31 scale for dysautonomia (p=2.28x10-3) and on the motor evaluation using Movement Disorder Society (MDS)-sponsored revision of Unified Parkinson’s Disease Rating Scale motor subscore (UPDRS-III) (p=1.84x10-4), compared with healthy controls. Home polysomnogram did not find participants with REM-sleep behavior disorder. Integrity of nigrostriatal dopaminergic system was evaluated by PET-CT imaging of presynaptic dopamine with 18F-PR04.MZ. Patients showed significantly higher specific binding ratios in the striatum, compared to controls (p=9.57x10-3 at the caudate nuclei). Two patients with 22qDS (5.2%) had decreased uptake in the posterior putamen (less than 60% of controls) and one fulfilled MDS criteria for prodromal PD. These results show that patients with 22qDS manifest some signs and symptoms of prodromal PD such as hyposmia, dysautonomia and mild movement alterations. In the majority, this was associated with elevated dopaminergic signaling, suggesting that loss of dopaminergic neurons may not be the cause. A smaller subgroup did show evidence of a decrease in nigrostriatal dopaminergic signaling, as seen in classical prodromal PD. Longitudinal studies are necessary to understand the progression to and risk of PD in persons with 22qDS.