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Rochedy A, Valette M, Tauber M, Poulain JP. Food socialization of children with Prader-Willi syndrome: an interdisciplinary problematization. Front Nutr 2023; 10:1177348. [PMID: 37346908 PMCID: PMC10280295 DOI: 10.3389/fnut.2023.1177348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/10/2023] [Indexed: 06/23/2023] Open
Abstract
Eating "disorders" of people with Prader-Willi syndrome are frequently reported in the biomedical literature. The eating behaviors are presented as a syndrome-specific trajectory over the course of a lifetime. Infants initially show anorexic behavior, which then develops into hyperphagia that lasts from childhood to adulthood and is characterized by strong cravings for food and relentless thinking about it. However, the sociocultural determinants of these food practices are not fully understood. In the first section of this article, we carry out a literature review of medical articles published on disordered eating in children with PWS. The second section draws on a social science perspective and offers an interdisciplinary problematization using the concept of food socialization. To conclude, the third section explores the challenges facing research and new questions that emerge from the alternative problematization that is the PWS Food Social Norms Internalization (FSNI) theory.
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Affiliation(s)
- Amandine Rochedy
- Université Toulouse—Jean Jaurès, Toulouse, France
- UMR5044 Centre d'Etude et de Recherche Travail, Organisation, Pouvoir (CERTOP), Toulouse, Midi-Pyrénées, France
| | - Marion Valette
- Reference Center of Prader-Willi Syndrome and Other Syndromes with Eating Disorders PRADORT, Children’s Hospital, Toulouse, France
- UMR1295, Centre for Epidemiology and Research in Population Health (CERPOP), Toulouse, France
| | - Maithé Tauber
- Reference Center of Prader-Willi Syndrome and Other Syndromes with Eating Disorders PRADORT, Children’s Hospital, Toulouse, France
- INSERM UMR1291 Institut Toulousain des Maladies Infectieuses et Inflammatoires, Toulouse, France
| | - Jean Pierre Poulain
- Université Toulouse—Jean Jaurès, Toulouse, France
- UMR5044 Centre d'Etude et de Recherche Travail, Organisation, Pouvoir (CERTOP), Toulouse, Midi-Pyrénées, France
- Chair of “Food Studies: Food, Cultures and Health”, Taylor’s Toulouse University Center, Taylor’s University, Kuala Lumpur, Malaysia
- Faculty of Social Sciences and Leisure Management and Centre for Asian Modernisation Studies, Taylor’s University, Kuala Lumpur, Malaysia
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2
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Strelnikov K, Debladis J, Salles J, Valette M, Cortadellas J, Tauber M, Barone P. Amygdala hyperactivation relates to eating behaviour: a potential indicator of food addiction in Prader-Willi syndrome. Brain Commun 2023; 5:fcad138. [PMID: 37168732 PMCID: PMC10165245 DOI: 10.1093/braincomms/fcad138] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/26/2023] [Accepted: 04/26/2023] [Indexed: 05/13/2023] Open
Abstract
Prader-Willi syndrome is a rare neurodevelopmental genetic disorder characterized by various endocrine, cognitive and behavioural problems. The symptoms include an obsession for food and reduced satiety, which leads to hyperphagia and morbid obesity. Neuropsychological studies have reported that Prader-Willi patients display altered social interactions with a specific weakness in interpreting social information and responding to them, a symptom close to that observed in autism spectrum disorders. In the present case-control study, we hypothesized that brain regions associated with compulsive eating behaviour would be abnormally activated by food-related odours in Prader-Willi syndrome, as these can stimulate the appetite and induce hunger-related behaviour. We conducted a brain imaging study using the olfactory modality because odours have a high-hedonic valence and can cause stronger emotional reactions than other modalities. Further, the olfactory system is also intimately associated with the endocrine regulation of energy balance and is the most appropriate modality for studies of Prader-Willi syndrome. A total of 16 Prader-Willi participants were recruited for this study, which is a significant achievement given the low incidence rate of this rare disease. The second group of 11 control age-matched subjects also participated in the brain imaging study. In the MRI scanner, using an MRI-compatible olfactometer during 56 block sessions, we randomly presented two odours (tulip and caramel), which have different hedonic valence and a different capacity to arouse hunger-related behaviour. Our results demonstrate that Prader-Willi participants have abnormal activity in the brain reward system that regulates eating behaviour. Indeed, we found that these patients had right amygdala activity up to five times higher in response to a food odour (caramel) compared with the tulip odour. In contrast, age-matched control participants had similar activity levels in response to both odours. The amygdala activity levels were found to be associated with the severity of the hyperphagia in Prader-Willi patients. Our results provide evidence for functional alteration of the right amygdala in Prader-Willi syndrome, which is part of the brain network involved in food addiction modulated by the ghrelin and oxytocin systems, which may drive the hyperphagia. Our study provides important new insights into the functioning of emotion-related brain circuits and pathology, and it is one of the few to explore the dysfunction of the neural circuits involved in emotion and addiction in Prader-Willi syndrome. It suggests new directions for the exploration and remediation of addictive behaviours.
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Affiliation(s)
- Kuzma Strelnikov
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse 31052, France
- Brain & Cognition Research Center (CerCo), CNRS, Toulouse 31052, France
- ENT Department, Purpan Hospital, Toulouse 31059, France
| | - Jimmy Debladis
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse 31052, France
- Brain & Cognition Research Center (CerCo), CNRS, Toulouse 31052, France
| | - Juliette Salles
- Department of Psychiatry, University Hospital of Toulouse, CHU, Toulouse 31059, France
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity) INSERM UMR1291 - CNRS UMR5051, Université Toulouse III, Toulouse 31024, France
| | - Marion Valette
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse 31059, France
| | - Julie Cortadellas
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse 31059, France
| | - Maithé Tauber
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity) INSERM UMR1291 - CNRS UMR5051, Université Toulouse III, Toulouse 31024, France
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse 31059, France
| | - Pascal Barone
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse 31052, France
- Brain & Cognition Research Center (CerCo), CNRS, Toulouse 31052, France
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3
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Downs J, Blackmore AM, Chen W, Nixon GM, Choong CS. Strengths and challenging behaviors in children and adolescents with Prader-Willi syndrome: Two sides to the coin. Am J Med Genet A 2022; 188:1488-1496. [PMID: 35092339 DOI: 10.1002/ajmg.a.62671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/22/2021] [Accepted: 12/30/2021] [Indexed: 11/09/2022]
Abstract
Prader-Willi Syndrome (PWS) is a rare genetic disorder associated with emotional/behavioral disturbances. These difficulties are well documented in the literature, but the positive attributes of these individuals are not described. Taking a strengths-based approach, the aim of this study was to describe the emotional/behavioral strengths and difficulties in children and young people with PWS from their parent caregivers' perspectives. Parent caregivers of 52 individuals with PWS aged 4-24 years (median = 12.1 years; including 22 males) completed the parent form of the Developmental Behavior Checklist (DBC-P), including its original two open-ended questions regarding positive traits. Prevalences of emotional/behavioral disturbances were comparable to those reported in previous literature: common behaviors of concern across studies being skin-picking (75%), impulsivity (69%), poor sense of danger (67%), lying (67%), and tantrums (54%). Total DBC-P scores showed that just over half (n = 28, 54%) had scores indicative of clinically significant behavior problems. However, thematic analysis of caregivers' written comments regarding their children's strengths resolved into three themes: warmth (94%), persistence (41%), and skills (41%). Warmth encompassed friendliness, happiness, and empathy. A strength-based approach to behavioral difficulties in PWS provides a more balanced view of the children and a more holistic foundation for interventions.
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Affiliation(s)
- Jenny Downs
- Child Disability, Telethon Kids Institute, Nedlands, Western Australia, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Bentley, Western Australia, Australia
| | - A Marie Blackmore
- Child Disability, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Wai Chen
- Youth Mental Health, Fiona Stanley Hospital, Murdoch, Western Australia, Australia.,Graduate School of Education, The University of Western Australia, Nedlands, Australia
| | - Gillian M Nixon
- Department of Pediatric Pulmonology, Erasmus University Medical Centre, Sophia Children's Hospital, Rotterdam, The Netherlands.,Melbourne Children's Sleep Centre, Monash Children's Hospital, Clayton, Victoria, Australia
| | - Catherine S Choong
- Department of Endocrinology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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Mortillo M, Mulle JG. A cross-comparison of cognitive ability across 8 genomic disorders. Curr Opin Genet Dev 2021; 68:106-116. [PMID: 34082144 DOI: 10.1016/j.gde.2021.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/01/2021] [Accepted: 04/08/2021] [Indexed: 12/23/2022]
Abstract
Genomic disorders result from rearrangement of the human genome. Most genomic disorders are caused by copy number variants (CNV), deletions or duplications of several hundred kilobases. Many CNV loci are associated with autism, schizophrenia, and most commonly, intellectual disability (ID). However, there is little comparison of cognitive ability measures across these CNV disorders. This study aims to understand whether existing data can be leveraged for a cross-comparison of cognitive ability among multiple CNV. We found there is a lack of harmonization among assessment instruments and little standardization for reporting summary data across studies. Despite these limitations, we identified a differential impact of CNV loci on cognitive ability. Our data suggest that future cross-comparisons of CNV disorders will reveal meaningful differences across the phenotypic spectrum, especially if standardized phenotypic assessment is achieved.
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Affiliation(s)
- Michael Mortillo
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Jennifer G Mulle
- Department of Human Genetics, Emory University, Atlanta, GA, United States.
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Strelnikov K, Hervault M, Laurent L, Barone P. When two is worse than one: The deleterious impact of multisensory stimulation on response inhibition. PLoS One 2021; 16:e0251739. [PMID: 34014959 PMCID: PMC8136741 DOI: 10.1371/journal.pone.0251739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 05/01/2021] [Indexed: 11/18/2022] Open
Abstract
Multisensory facilitation is known to improve the perceptual performances and reaction times of participants in a wide range of tasks, from detection and discrimination to memorization. We asked whether a multimodal signal can similarly improve action inhibition using the stop-signal paradigm. Indeed, consistent with a crossmodal redundant signal effect that relies on multisensory neuronal integration, the threshold for initiating behavioral responses is known for being reached faster with multisensory stimuli. To evaluate whether this phenomenon also occurs for inhibition, we compared stop signals in unimodal (human faces or voices) versus audiovisual modalities in natural or degraded conditions. In contrast to the expected multisensory facilitation, we observed poorer inhibition efficiency in the audiovisual modality compared with the visual and auditory modalities. This result was corroborated by both response probabilities and stop-signal reaction times. The visual modality (faces) was the most effective. This is the first demonstration of an audiovisual impairment in the domain of perception and action. It suggests that when individuals are engaged in a high-level decisional conflict, bimodal stimulation is not processed as a simple multisensory object improving the performance but is perceived as concurrent visual and auditory information. This absence of unity increases task demand and thus impairs the ability to revise the response.
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Affiliation(s)
- Kuzma Strelnikov
- Brain & Cognition Research Center (CerCo), University of Toulouse 3 –CNRS, Toulouse, France
- Purpan University Hospital, Toulouse, France
- * E-mail:
| | - Mario Hervault
- Brain & Cognition Research Center (CerCo), University of Toulouse 3 –CNRS, Toulouse, France
| | - Lidwine Laurent
- Brain & Cognition Research Center (CerCo), University of Toulouse 3 –CNRS, Toulouse, France
| | - Pascal Barone
- Brain & Cognition Research Center (CerCo), University of Toulouse 3 –CNRS, Toulouse, France
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The RDoC approach for translational psychiatry: Could a genetic disorder with psychiatric symptoms help fill the matrix? the example of Prader-Willi syndrome. Transl Psychiatry 2020; 10:274. [PMID: 32772048 PMCID: PMC7415132 DOI: 10.1038/s41398-020-00964-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022] Open
Abstract
The Research Domain Criteria project (RDoc) proposes a new classification system based on information from several fields in order to encourage translational perspectives. Nevertheless, integrating genetic markers into this classification has remained difficult because of the lack of powerful associations between targeted genes and RDoC domains. We hypothesized that genetic diseases with psychiatric manifestations would be good models for RDoC gene investigations and would thereby extend the translational approach to involve targeted gene pathways. To explore this possibility, we reviewed the current knowledge on Prader-Willi syndrome, a genetic disorder caused by the absence of expression of some of the genes of the chromosome 15q11-13 region inherited from the father. Indeed, we found that the associations between genes of the PW locus and the modification identified in the relevant behavioral, physiological, and brain imaging studies followed the structure of the RDoC matrix and its six domains (positive valence, negative valence, social processing, cognitive systems, arousal/regulatory systems, and sensorimotor systems).
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Strenilkov K, Debladis J, Salles J, Valette M, Mantoulan C, Thuilleaux D, Laurier V, Molinas C, Barone P, Tauber M. A study of voice and non-voice processing in Prader-Willi syndrome. Orphanet J Rare Dis 2020; 15:22. [PMID: 31959191 PMCID: PMC6972021 DOI: 10.1186/s13023-020-1298-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/08/2020] [Indexed: 11/23/2022] Open
Abstract
Background Prader-Willi syndrome (PWS) is a rare and complex neurodevelopmental disorder of genetic origin. It manifests itself in endocrine and cognitive problems, including highly pronounced hyperphagia and severe obesity. In many cases, impaired acquisition of social and communication skills leads to autism spectrum features, and individuals with this syndrome are occasionally diagnosed with autism spectrum disorder (ASD) using specific scales. Given that communicational skills are largely based on vocal communication, it is important to study human voice processing in PWS. We were able to examine a large number of participants with PWS (N = 61) recruited from France’s national reference center for PWS and other hospitals. We tested their voice and nonvoice recognition abilities, as well as their ability to distinguish between voices and nonvoices in a free choice task. We applied the hierarchical drift diffusion model (HDDM) with Bayesian estimation to compare decision-making in participants with PWS and controls. Results We found that PWS participants were impaired on both voice and nonvoice processing, but displayed a compensatory ability to perceive voices. Participants with uniparental disomy had poorer voice and nonvoice perception than participants with a deletion on chromosome 15. The HDDM allowed us to demonstrate that participants with PWS need to accumulate more information in order to make a decision, are slower at decision-making, and are predisposed to voice perception, albeit to a lesser extent than controls. Conclusions The categorization of voices and nonvoices is generally preserved in participants with PWS, though this may not be the case for the lowest IQ.
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Affiliation(s)
- Kuzma Strenilkov
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France. .,Brain & Cognition Research Center (CerCo), CNRS, Toulouse, France. .,ENT Department, Purpan Hospital, Toulouse, France.
| | - Jimmy Debladis
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France.,Brain & Cognition Research Center (CerCo), CNRS, Toulouse, France
| | - Juliette Salles
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France.,Brain & Cognition Research Center (CerCo), CNRS, Toulouse, France.,Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | - Marion Valette
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | - Carine Mantoulan
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | | | | | - Catherine Molinas
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | - Pascal Barone
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France.,Brain & Cognition Research Center (CerCo), CNRS, Toulouse, France
| | - Maïthé Tauber
- Prader-Willi Syndrome Reference Center, Children's Hospital-INSERM-University of Toulouse Paul Sabatier, Toulouse, France.,Toulouse Purpan Physiopathology Center, INSERM-University of Toulouse Paul Sabatier, Toulouse, France
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Holland AJ, Aman LC, Whittington JE. Defining Mental and Behavioural Disorders in Genetically Determined Neurodevelopmental Syndromes with Particular Reference to Prader-Willi Syndrome. Genes (Basel) 2019; 10:genes10121025. [PMID: 31835392 PMCID: PMC6947448 DOI: 10.3390/genes10121025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/29/2019] [Accepted: 12/03/2019] [Indexed: 11/29/2022] Open
Abstract
Genetically determined neurodevelopmental syndromes are frequently associated with a particular developmental trajectory, and with a cognitive profile and increased propensity to specific mental and behavioural disorders that are particular to, but not necessarily unique to the syndrome. How should these mental and behavioural disorders best be conceptualised given that similar symptoms are included in the definition of different mental disorders as listed in DSM-5 and ICD-10? In addition, a different conceptual framework, that of applied behavioural analysis, has been used to inform interventions for what are termed ‘challenging behaviours’ in contrast to types of interventions for those conditions meeting diagnostic criteria for a ‘mental disorder’. These syndrome-specific developmental profiles and associated co-morbidities must be a direct or indirect consequence of the genetic abnormality associated with that syndrome, but the genetic loci associated with the syndrome may not be involved in the aetiology of similar symptoms in the general population. This being so, should we expect underlying brain mechanisms and treatments for specific psychopathology in one group to be effective in the other? Using Prader-Willi syndrome as an example, we propose that the conceptual thinking that informed the development of the Research Domain Criteria provides a model for taxonomy of psychiatric and behavioural disorders in genetically determined neurodevelopmental syndromes. This model brings together diagnostic, psychological and developmental approaches with the aim of matching specific behaviours to identifiable neural mechanisms.
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Debladis J, Valette M, Strenilkov K, Mantoulan C, Thuilleaux D, Laurier V, Molinas C, Barone P, Tauber M. Face processing and exploration of social signals in Prader-Willi syndrome: a genetic signature. Orphanet J Rare Dis 2019; 14:262. [PMID: 31730500 PMCID: PMC6858697 DOI: 10.1186/s13023-019-1221-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/09/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Faces are critical social cues that must be perfectly processed in order to engage appropriately in everyday social interactions. In Prader-Willi Syndrome (PWS), a rare genetic disorder characterized by cognitive and behavioural difficulties including autism spectrum disorder, the literature referring to face processing is sparse. Given reports of poor social interactions in individuals with PWS, we sought to assess their face and emotion recognition skills during eyetracking recordings. RESULTS Compared with controls, patients with PWS performed more poorly on face/emotion recognition. We observed atypical facial exploration by patients with maternal disomy. These patients looked preferentially at the mouth region, whereas patients with a deletion and controls were more attracted to the eye region. During social scenes, the exploration became more atypical as the social content increased. CONCLUSIONS Our comprehensive study brings new insights into the face processing of patients with PWS. Atypical facial exploration was only displayed by patients with the maternal disomy subtype, corresponding to their higher rate of autism spectrum disorder. This finding strongly argues in favor of early identification of this genetic subgroup in order to optimize care by implementing tailored interventions for each patient as soon as possible.
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Affiliation(s)
- Jimmy Debladis
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France. .,Brain & Cognition Research Center (CerCo), CNRS, Purpan Faculty of Medicine, Toulouse, France. .,Cerveau & Cognition, CNRS UMR 5549, Pavillon Baudot, CHU Purpan, BP 25202, 31052, Toulouse Cedex, France.
| | - Marion Valette
- Prader-Willi Syndrome Reference Center, Children's Hospital, Toulouse, France
| | | | - Carine Mantoulan
- Prader-Willi Syndrome Reference Center, Children's Hospital, Toulouse, France
| | | | | | - Catherine Molinas
- Prader-Willi Syndrome Reference Center, Children's Hospital, Toulouse, France
| | - Pascal Barone
- Brain & Cognition Research Center (CerCo), University of Toulouse Paul Sabatier, Toulouse, France.,Brain & Cognition Research Center (CerCo), CNRS, Purpan Faculty of Medicine, Toulouse, France
| | - Maïthé Tauber
- Prader-Willi Syndrome Reference Center, Children's Hospital, Toulouse, France.,Toulouse-Purpan Physiopathology Center, INSERM, Toulouse, France
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Mechanistic insights into the genetics of affective psychosis from Prader-Willi syndrome. Lancet Psychiatry 2018; 5:370-378. [PMID: 29352661 DOI: 10.1016/s2215-0366(18)30009-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 10/19/2017] [Accepted: 10/26/2017] [Indexed: 12/14/2022]
Abstract
Schizophrenia and bipolar disorder are common, severe, and disabling psychotic disorders, which are difficult to research. We argue that the genetically determined neurodevelopmental disorder Prader-Willi syndrome (PWS), which is associated with a high risk of affective psychotic illness, can provide a window into genetic mechanisms and associated neural pathways. People with PWS can all show non-psychotic psychopathology and problem behaviours, but the prevalence of psychotic illness differs markedly by genetic subtype; people with PWS due to chromosome 15 maternal uniparental disomy have higher prevalence of psychotic illness compared with patients with PWS due to 15q11-13 deletions of paternal origin. On the basis of this observation and the neural differences between genetic subtypes, we hypothesise that the combined effects of the absent expression of specific maternally imprinted genes at 15q11-13, and excess maternally imprinted or paternally expressed genes on chromosome 15, affect the γ-aminobutyric acid-glutamatergic pathways and associated neural networks that underpin mood regulation and sensory processing, resulting in psychotic illness. We propose a model of potential mechanisms of psychosis in PWS, which might be relevant in the general population, and should inform future research.
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