Genetic contributions to the etiology of anorexia nervosa: New perspectives in molecular diagnosis and treatment

Revealing the effects of various immune cells in anorexia nervosa: Evidence from Mendelian randomization

The aim of this study was to assess the causal relationship between immune cells and anorexia nervosa (AN) by Mendelian randomization (MR). Data on immune cell phenotypes and AN were obtained from genome-wide association studies. Next, single nucleotide polymorphisms included in the MR analysis were screened according the basic assumptions. Furthermore, inverse variance weighted was used as the main method for MR analysis to evaluate the causal effect of immune cell phenotypes on AN. Finally, MR-Egger intercept, Cochran Q, and leave-one-out sensitivity analyses were used to assess horizontal pleiotropy, heterogeneity, and robustness, respectively. The MR analysis showed that NKT %lymphocyte (OR 1.201, 95% CI = 1.021-1.411, P = .027), NKT %T cell (OR 1.258, 95%CI 1.043-1.519, P = .017), double negative (DN) (CD4-CD8-) NKT %lymphocyte (OR 1.235, 95%CI 1.074-1.420, P = .003), DN (CD4-CD8-) NKT %T cell (OR 1.222, 95%CI 1.060-1.410, P = .006), CD8dim NKT absolute count (OR 1.225, 95%CI 1.045-1.436, P = .012), CD8dim NKT %lymphocyte (OR 1.214, 95%CI 1.043-1.414, P = .012), CD8dim NKT %T cell (OR 1.215, 95%CI 1.035-1.425, P = .017), CD16-CD56 on NKT (OR 1.193, 95%CI 1.014-1.402, P = .033), CD28 + CD45RA + CD8br %T cell (OR 1.020, 95%CI 1.002-1.037, P = .025) were associated with increased genetic susceptibility to AN. MR-Egger showed no horizontal pleiotropy (P ≥ .05). Cochran Q and sensitivity analysis showed that the results were not heterogeneous and were robust. This MR analysis revealed 9 immune cell phenotypes related to increased genetic susceptibility to AN, emphasizing the importance of NKT and CD8 in AN. This finding provides new insights for understanding the pathogenesis of AN and developing immune-targeted drugs.

Contemporary reflections on William Gull's case studies of anorexia nervosa, 150 years on

OBJECTIVE

To analyse and compare the original four published anorexia nervosa (AN) case histories of William Gull with modern-day approaches.

METHOD

Case histories of the patients described by Gull were reviewed and placed in a tabulated format (which included demographics, clinical presentation, treatment, and prognosis) along with his general comments on AN, for easier comparison.

RESULTS

Many of the presenting features of AN are similar to cases seen in more modern times but lack weight or body image disturbances. The cases described by Gull can be categorised as AN under the Diagnostic and Statistical Manual-Fifth Edition (DSM-5) and the Text Revision (DSM-5-TR) however, they were excluded by the Diagnostic and Statistical Manual-Fourth Edition (DSM-IV) and the International Classification of Diseases-10th Revision (ICD-10) criteria. Reference to Gull's work might have avoided the necessary change in diagnostic criteria.

CONCLUSIONS

150 years on, Gull's cases resemble presentations of AN without weight or body image issues and emphasise the heterogeneity of the diagnostic conceptualisation of AN in the modern era. Nutritional rehabilitation remains core to the treatment with other interventions supporting this goal while aetiology remains elusive.

Parent-daughter emotional dyssynchrony correlates with personality and psychopathology in adolescents with anorexia nervosa

PURPOSE

Anorexia nervosa (AN) is a major concern in adolescents. Attachment problems contribute to its pathogenesis and maintenance. This research explores the relationship between parent-daughter emotional dyssynchrony and the psychopathology of AN daughters.

METHODS

One hundred and fourteen female adolescents with AN and their parents participated in this study. The daughters completed the youth self-report (YSR) and other self-report measures of personality, eating, and general psychopathology. The parents completed the Child Behavior Checklist (CBCL). The YSR and CBCL ratings were compared and the difference was considered a measure of emotional dyssynchrony. Dyssynchrony scores were correlated with daughters' personality and psychopathology.

RESULTS

Mothers scored lower on 15/21 (71%), and fathers scored lower on 11/21 (52%). Mothers scored higher than fathers did in thought problems. Mothers' dyssynchrony was positively related to their daughters' harm avoidance and negatively related to their self-directedness. Both parents' dyssynchrony correlated with their daughters' eating habits and general psychopathology. Dyssynchrony in each psychopathological measure of YSR was positively correlated with specific daughters' psychopathological traits.

CONCLUSIONS

Parents' perceptions underestimate the suffering of adolescents with AN. Mothers' perception was worse than that of fathers, possibly because of greater overinvolvement. Parent-daughter dyssynchrony is largely related to daughters' psychopathology. This cross-sectional study could not confirm whether dyssynchrony contributed to the onset of AN or follows it. Interventions that promote emotional synchronization may aid in the treatment of adolescents with AN.

LEVEL OF EVIDENCE

III.

A Systematic Review to Explore a Neuropsychological Profile that Predates Anorexia Nervosa

OBJECTIVE

Research demonstrates reduced cognitive flexibility and weak central coherence during acute illness and following recovery from anorexia nervosa (AN). This systematic review investigated if these impairments are present in first-degree relatives of individuals with AN, representing a possible neuropsychological risk profile.

METHODS

A systematic review of electronic databases was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search ended on July 14, 2023. Established search terms and inclusion criteria identified relevant research. Risk of bias was assessed using the Critical Appraisal Skills Program. The review was registered with Prospero international prospective register of systematic reviews (No. CRD42023401268). Study selection, descriptive data, critical appraisal, and risk of bias are presented in tables and figures.

RESULTS

The search yielded 10 studies. The included studies conducted neuropsychological assessments of discordant AN relatives and lifetime longitudinal study participants. Most studies found cognitive flexibility and central coherence to be significantly reduced in participants with AN and their relatives compared with controls. One study found decision making to be significantly impaired in AN participants and relatives. Effect sizes were moderate to large.

DISCUSSION

Reduced cognitive flexibility and weak central coherence appear to be endophenotypes of AN. Further research is required with relatives concordant for AN to establish whether these biomarkers co-segregate with AN within families. These findings suggest a possibility of developing screeners to identify individuals at risk of AN allowing for early intervention.

Anorexia nervosa in children and adolescents: an early detection of risk factors

The incidence of eating disorders in children, mainly of anorexia nervosa, is dramatically increased in the last years. A timely identification of the disease is associated with higher rates of recovery. Aim of the work is to underline signs and symptoms that can be used to an early detection of anorexia nervosa in the pediatric age. A scoping review has been conducted by The Italian Pediatric Society Adolescent Study Group according to the PRISMA Extension guidelines for Scoping Reviews, using the search term "anorexia nervosa" and the following filters "review", "systematic review", "age 0-18", "last 4 years". The strategy search produced 657 studies, of which 52 were included in this revision. Screening and red flags were discussed in 23 reports, genetics in 12, neurological pathways in 11, environmental factors in 10, and gut microbiota in 7. An accurate physiological and pathological anamnesis, physical and psychological examination, including the body perception, should be taken in account as well as the presence of co-morbidities, including chronic functional abdominal pain and autoimmune/autoinflammatory diseases. Evidence suggests the role of familiar predisposition as well as of neurological morphology and pathway in anorexia nervosa development. Gut microbiota has also been included among possible risk factor for developing anorexia nervosa due to a complex direct and indirect interactions between gut and brain. The Italian Pediatric Society Adolescent Study Group suggests performing an accurate familial and personal anamnesis, including psychological evaluation as well as a physical exam including auxological parameters as a screening tool during pediatric checks to better explore the risk of developing anorexia nervosa.

Effectiveness of Yoga as a Complementary Therapy for Anorexia Nervosa: A Systematic Review

Anorexia nervosa (AN) is a severe psychiatric condition associated with high disability and mortality. The purpose of the present manuscript is to critically summarize evidence about the effectiveness of yoga for this condition. A bibliographic search was conducted in the main database sources (PubMed, Embase, and Scopus). Articles in English about the effectiveness of yoga in AN were included. Two hundred thirty-three articles were initially identified and 5 articles were included in the present review. With the exception of one study, all had several methodological limitations such as the presence of confounding factors (e.g., psychiatric comorbidity) or a too limited sample of patients. However, globally yoga seems to ameliorate AN symptoms, especially those regarding emotional dysregulation. Yoga is a candidate complementary treatment for the management of AN, but more randomized controlled studies with larger samples and limited bias are necessary to draw robust conclusions. It would be also interesting to verify in comparative trials the effectiveness of yoga with respect to other treatments such as psychotherapy or the administration of pharmacological compounds. Finally, the practice should be modified adapting to the specific needs of this type of patient.

Longitudinal Impact of Disordered Eating Attitudes on Depression, Anxiety, and Somatization in Young Women with Anorexia and Bulimia

Background/Objectives: Eating disorders, characterized by severe disturbances in eating behavior, are a public health concern, particularly among young women. This longitudinal study aimed to investigate the relationship between disordered eating attitudes and mental health outcomes, including depression, anxiety, and somatization, among individuals with eating disorders. Methods: A total of 471 young German women hospitalized with anorexia nervosa or bulimia nervosa participated in this study. Assessments were conducted at two points over a two-month interval using the Eating Disorder Inventory-2 (EDI-2) and the Patient Health Questionnaire. Regression analyses were performed to determine predictors of depression, anxiety, and somatization. The study controlled for socio-demographic segmentation using Sinus-Milieus, a social classification system, as a covariate. Results: Regression analyses revealed that interpersonal distrust and impulse regulation were significant predictors of subsequent depression. Impulse regulation strongly predicted subsequent anxiety, while both impulse regulation and social insecurity were strong predictors of subsequent somatization. The Neo-Ecological Milieu emerged as the most prevalent socio-demographic group (34.4% of participants). The Sinus-Milieus segmentation, however, did not significantly impact the health outcomes, suggesting consistent mental health issues across socio-demographic groups. Conclusions: This study's findings underscored the role of disordered eating attitudes in predicting mental health outcomes among young women with eating disorders. Addressing these attitudes in therapeutic settings may help mitigate symptoms of not only the primary condition but also depression, anxiety, and somatization.

Genetic polymorphisms and their association with neurobiological and psychological factors in anorexia nervosa: a systematic review

Background and aims

Anorexia nervosa (AN) is a complex neuropsychiatric disorder. This systematic review synthesizes evidence from diverse studies to assess and investigate the association between gene polymorphisms and psychological and neurobiological factors in patients with AN.

Methods

A systematic search across PubMed, PsycINFO, Scopus, and Web of Science databases, along with manual searching, was conducted. The review protocol was approved by PROSPERO (CRD42023452548). Out of 1,250 articles, 11 met the inclusion criteria. The quality of eligible articles was assessed using the Newcastle-Ottawa Scale (NOS) tool. The systematic review followed the PRISMA guidelines.

Results

The serotoninergic system, particularly the 5-HTTLPR polymorphism, is consistently linked to altered connectivity in the ventral attention network, impaired inhibitory control, and increased susceptibility to AN. The 5-HTTLPR polymorphism affects reward processing, motivation, reasoning, working memory, inhibition, and outcome prediction in patients with AN. The dopaminergic system, involving genes like COMT, DRD2, DRD3, and DAT1, regulates reward, motivation, and decision-making. Genetic variations in these dopaminergic genes are associated with psychological manifestations and clinical severity in patients with AN. Across populations, the Val66Met polymorphism in the BDNF gene influences personality traits, eating behaviors, and emotional responses. Genes like OXTR, TFAP2B, and KCTD15 are linked to social cognition, emotional processing, body image concerns, and personality dimensions in patients with AN.

Conclusion

There was an association linking multiple genes to the susceptibly and/or severity of AN. This genetic factor contributes to the complexity of AN and leads to higher diversity of its clinical presentation. Therefore, conducting more extensive research to elucidate the underlying mechanisms of anorexia nervosa pathology is imperative for advancing our understanding and potentially developing targeted therapeutic interventions for the disorder.Systematic review registration: [https://clinicaltrials.gov/], identifier [CRD42023452548].

Association of serotonin receptor gene polymorphisms with anorexia nervosa: a systematic review and meta-analysis

PURPOSE

Several studies have investigated the association between anorexia nervosa and polymorphisms of genes regulating serotonin neurotransmission, with a focus on the rs6311 polymorphism of 5-HTR2A. However, inconsistent results of these studies and conflicting conclusions of existing meta-analyses complicate the understanding of a possible association. We have updated these results and evaluated the involvement of other serotonin receptor gene polymorphisms in anorexia nervosa.

METHODS

Adhering to PRISMA guidelines, we have searched studies on anorexia nervosa and serotonin-regulating genes published from 1997 to 2022, selected those concerning receptor genes and meta-analyzed the results from twenty candidate gene studies on the 5-HTR2A rs6311 polymorphism and the 5-HTR2C rs6318 polymorphism.

RESULTS

Present analyses reveal an association for the 5-HTR2A rs6311 polymorphism, with G and A alleles, across eighteen studies (2049 patients, 2877 controls; A vs. G allele, Odds Ratio = 1.24; 95% Confidence Interval = 1.06-1.47; p = 0.009). However, after geographic subgrouping, an association emerged only in a Southern European area, involving five studies (722 patients, 773 controls; A vs. G allele, Odds Ratio = 1.82; 95% Confidence Interval = 1.41-2.37; p < 0.00001). No association was observed for the 5-HTR2C rs6318 polymorphism across three studies.

CONCLUSIONS

To date, the involvement in the pathophysiology of anorexia nervosa of the 5-HTR2A rs6311 polymorphism appears limited to a specific genetic and/or environmental context, while that of the 5-HTR2C rs6318 polymorphism seems excluded. Genome-wide association studies and epigenetic studies will likely offer deeper insights of genetic and environmental factors possibly contributing to the disorder.

LEVEL OF EVIDENCE

III Evidence obtained from well-designed cohort or case-control analytic studies. Clinical trial registration PROSPERO registration number: CRD42021246122.

Unexpected identification of obesity-associated mutations in LEP and MC4R genes in patients with anorexia nervosa

Mutations leading to a reduced or loss of function in genes of the leptin-melanocortin system confer a risk for monogenic forms of obesity. Yet, gain of function variants in the melanocortin-4-receptor (MC4R) gene predispose to a lower BMI. In individuals with reduced body weight, we thus expected mutations leading to an enhanced function in the respective genes, like leptin (LEP) and MC4R. Therefore, we have Sanger sequenced the coding regions of LEP and MC4R in 462 female patients with anorexia nervosa (AN), and 445 healthy-lean controls. In total, we have observed four and eight variants in LEP and MC4R, respectively. Previous studies showed different functional in vitro effects for the detected frameshift and non-synonymous variants: (1) LEP: reduced/loss of function (p.Val94Met), (2) MC4R: gain of function (p.Val103Ile, p.Ile251Leu), reduced or loss of function (p.Thr112Met, p.Ser127Leu, p.Leu211fsX) and without functional in vitro data (p.Val50Leut). In LEP, the variant p.Val94Met was detected in one patient with AN. For MC4R variants, one patient with AN carried the frameshift variant p.Leu211fsX. One patient with AN was heterozygous for two variants at the MC4R (p.Val103Ile and p.Ser127Leu). All other functionally relevant variants were detected in similar frequencies in patients with AN and lean individuals.

Neural Response to Expecting a Caloric Sweet Taste Stimulus Predicts Body Mass Index Longitudinally Among Young Adult Women With Anorexia Nervosa

BACKGROUND

Anorexia nervosa (AN) is an often-chronic illness, and we lack biomarkers to predict long-term outcome. Recent neuroimaging studies using caloric taste stimuli suggest that paradigms that have tested conditioned neural responses to expectation or salient stimulus receipt may underpin behaviors. However, whether activation of those neural circuits can predict long-term outcome has not been studied.

METHODS

We followed women treated for AN (n = 35, mean age [SD] = 23 [7] years) and tested whether functional imaging brain response during a taste conditioning paradigm could predict posttreatment body mass index (BMI). We anticipated greater neural activity relative to caloric stimulus expectation and that dopamine-related receipt conditions would predict lower posttreatment BMI, indicating fear-associated arousal.

RESULTS

Follow-up occurred at mean (SD) = 1648 (1216) days after imaging. Stimulus expectation in orbitofrontal and striatal regions and BMI and BMI change at follow-up were negatively correlated, and these correlations remained significant for the right superior orbitofrontal cortex and BMI change after multiple comparison correction (r = -0.484, p = .003). This relationship remained significant after including time between brain scanning and follow-up in the model. Reward prediction error response did not predict long-term BMI.

CONCLUSIONS

The orbitofrontal cortex is involved in learning and conditioning, and these data implicate this region in learned caloric stimulus expectation and long-term prediction of weight outcomes in AN. Thus, conditioned elevated brain response to the anticipation of receiving a caloric stimulus may drive food avoidance, suggesting that breaking such associations is central for long-term recovery from AN.

Potential applications of Schema Therapy in the treatment of adolescents with anorexia nervosa: a theoretical analysis

Purpose

The main purpose of the article is to present basic theoretical assumptions on Schema Therapy and its hypothetical application among adolescents suffering with anorexia nervosa.

Views

Anorexia nervosa is a very deadly mental disease, more frequently suffered by females than males, with the mean age of onset at approximately 14-15. Studies underline the relatively poor effectiveness of currently applied treatment methods and the need for new approaches that could be recommended for adolescent patients suffering with this disease. The results of studies conducted to date lead to the conclusion that Schema Therapy is a promising approach for this group. It is a transdiagnostic method of work that compiles elements known in other therapeutic approaches, aiming at an increase in the individual's awareness of their feelings and emotional needs, applied both in adolescent and adult groups of patients. Since the symptoms of eating disorders observed in adolescents are strongly connected with family systems it seems reasonable to use treatment techniques that rigorously address the unmet needs and rejected emotions of the individual.

Conclusions

Based on the data published so far it might be hypothesized that the techniques characteristic for Schema Therapy (e.g. imagery rescripting, chairwork, limited reparenting) could be eligible for use with adolescent patients with anorexia nervosa.They address unmet needs, rejected emotions, and early maladaptive schemas that are very frequent in patients with AN. Since the analysis presented provides only hypotheses and the discussion of theoretical aspects, empirical research in this area is needed.

Natural compound targeting BDNF V66M variant: insights from in silico docking and molecular analysis

Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin gene family gene that encodes proteins vital for the growth, maintenance, and survival of neurons in the nervous system. The study aimed to screen natural compounds against BDNF variant (V66M), which affects memory, cognition, and mood regulation. BDNF variant (V66M) as a target structure was selected, and Vitamin D, Curcumin, Vitamin C, and Quercetin as ligands structures were taken from PubChem database. Multiple tools like AUTODOCK VINA, BIOVIA discovery studio, PyMOL, CB-dock, IMOD server, Swiss ADEMT, and Swiss predict ligands target were used to analyze binding energy, interaction, stability, toxicity, and visualize BDNF-ligand complexes. Compounds Vitamin D3, Curcumin, Vitamin C, and Quercetin with binding energies values of - 5.5, - 6.1, - 4.5, and - 6.7 kj/mol, respectively, were selected. The ligands bind to the active sites of the BDNF variant (V66M) via hydrophobic bonds, hydrogen bonds, and electrostatic interactions. Furthermore, ADMET analysis of the ligands revealed they exhibited sound pharmacokinetic and toxicity profiles. In addition, an MD simulation study showed that the most active ligand bound favorably and dynamically to the target protein, and protein-ligand complex stability was determined. The finding of this research could provide an excellent platform for discovering and rationalizing novel drugs against stress related to BDNF (V66M). Docking, preclinical drug testing and MD simulation results suggest Quercetin as a more potent BDNF variant (V66M) inhibitor and forming a more structurally stable complex.

Anorexia Nervosa in Adolescence: Parental Narratives Explore Causes and Responsibilities

BACKGROUND

Anorexia nervosa (AN) is a serious mental disorder with a multifactorial etiopathogenesis, adolescent girls being especially vulnerable. Parents can be a resource and occasionally a burden when their children suffer from AN; thus, parents play a key role in recovery. This study focused on parental illness theories of AN and how parents negotiate their responsibilities.

METHODS

To gain insights into this dynamic, 14 parents (11 mothers, 3 fathers) of adolescent girls were interviewed. Qualitative content analysis was used to provide an overview of the parents' assumed causes for their children's AN. We also looked for systematic differences in the assumed causes among different groups of parents (e.g., high versus low self-efficacy). A microgenetic positioning analysis of two mother-father dyads provided further insight into how they viewed the development of AN in their daughters.

RESULTS

The analysis stressed the overall helplessness of parents and their strong need to understand what was going on. Parents differed in stressing internal and external causes, which influenced whether they felt responsible and how much they felt in control and able to help.

CONCLUSIONS

Analysing the variability and dynamics shown can support therapists, especially those working systemically to change the narratives within families for better therapy compliance and outcomes.

Gender and sex in eating disorders: A narrative review of the current state of knowledge, research gaps, and recommendations

INTRODUCTION

Eating disorders (EDs) have long been considered conditions exclusively affecting women, and studies in the ED field regularly exclude men. Research efforts are needed to better understand the role of gender and sex in EDs. This review describes the role of gender and sex in the development of EDs from a biopsychosocial perspective.

METHODS

The primary hypothesis of this narrative review is that gender and sex interact to influence ED risk. The literature review was conducted using the PubMed database.

RESULTS

This review first presents the general characteristics and prevalence of EDs according to gender and sex. Next, neurodevelopmental processes, neurobiology, gender roles, body image, and the minority stress model are addressed. Lastly, research perspectives to better include gender and sex in the field of EDs are discussed (e.g., representation of gender and sex diversities, development of appropriate assessment tools, and increasing awareness).

CONCLUSION

Although substantial knowledge gaps remain, there is a growing recognition of the importance of integrating gender and sex in ED research that holds promise for further development in the field.

Gene variants in eating disorders. Focus on anorexia nervosa, bulimia nervosa, and binge-eating disorder

Eating disorders such as anorexia nervosa, bulimia nervosa and binge-eating disorder, have a deep social impact, concluding with death in cases of severe disease. Eating disorders affect up to 5% of the population in the industrialized countries, but probably the phenomenon is under-detection and under-diagnosis. Eating disorders are multifactorial disorders, resulting from the interaction between environmental triggers, psychological factors, but there is also a strong genetic component. In fact, genetic factors predispose for approximately 33-84% to anorexia nervosa, 28-83% to bulimia nervosa, and 41-57% to binge eating disorder. Twins and family studies have provided an unassailable proof on the heritability of these disorders. Other types of genetic studies, including genome-wide association studies, whole genome sequencing and linkage analysis, allowed to identify the genes and their variants associated with eating disorders and moreover global collaborative efforts have led to delineate the etiology of these disorders. Next Generation Sequencing technologies can be considered as an ideal diagnostic approach to identify not only the common variants, such as single nucleotide polymorphism, but also rare variants. Here we summarize the present knowledge on the molecular etiology and genetic determinants of eating disorders including serotonergic genes, dopaminergic genes, opioid genes, appetite regulation genes, endocannabinoid genes and vitamin D3.

Where Sex Meets Gender: How Sex and Gender Come Together to Cause Sex Differences in Mental Illness

Sex differences are prevalent in multiple mental disorders. Internalizing disorders are more commonly diagnosed in women, whereas externalizing and neurodevelopmental disorders are more often diagnosed in men. Significant sex/gender differences are reported in prevalence, symptom profile, age of onset, comorbidities, functional impairment, prognosis, as well as in responses to various treatments. In this conceptual article, we discuss theories and empirical studies of sex- and gender-related influences in mental health, by focusing on three examples: autism spectrum disorder (ASD), acknowledged as a disorder whose roots are mainly biological; eating disorders, whose origins are considered to be mainly psychosocial, and posttraumatic stress disorder (PTSD), an environmentally caused disorder with both psychosocial and biological underpinnings. We examine the ways in which sex differences emerge, from conception through adulthood. We also examine how gender dichotomies in exposures, expectations, role assumptions, and cultural traditions impact the expression of our three selected mental illnesses. We are especially interested in how sex-based influences and gender-based influences interact with one another to affect mental illness. We suggest that sex and gender are multi-faceted and complex phenomena that result in variations, not only between men and women, but also within each sex and gender through alterations in genes, hormone levels, self-perceptions, trauma experiences, and interpersonal relationships. Finally, we propose a conceptual diatheses-stress model, depicting how sex and gender come together to result in multiple sex/gender differences across mental disorders. In our model, we categorize diatheses into several categories: biological, intrapersonal, interpersonal, and environmental. These diatheses interact with exposure to stressors, ranging from relatively minor to traumatic, which allows for the sometimes bidirectional influences of acute and long-term stress responses. Sex and gender are discussed at every level of the model, thereby providing a framework for understanding and predicting sex/gender differences in expression, prevalence and treatment response of mental disorders. We encourage more research into this important field of study.

Main nutritional deficiencies

Nutrition is the source of energy that is required to carry out all the processes of human body. A balanced diet is a combination of both macro- and micronutrients. "Nutritional inadequacy" involves an intake of nutrients that is lower than the estimated average requirement, whereas "nutritional deficiency" consists of severely reduced levels of one or more nutrients, making the body unable to normally perform its functions and thus leading to an increased risk of several diseases like cancer, diabetes, and heart disease. Malnutrition could be caused by environmental factors, like food scarcity, as well as disease conditions, like anorexia nervosa, fasting, swallowing inability, persistent vomiting, impaired digestion, intestinal malabsorption, or other chronic diseases. Nutritional biomarkers - like serum or plasma levels of nutrients such as folate, vitamin C, B vitamins, vitamin D, selenium, copper, zinc - could be used for the evaluation of nutrient intake and dietary exposure. Macronutrients deficiencies could cause kwashiorkor, marasmus, ketosis, growth retardation, wound healing, and increased infection susceptibility, whereas micronutrient - like iron, folate, zinc, iodine, and vitamin A - deficiencies lead to intellectual impairment, poor growth, perinatal complications, degenerative diseases associated with aging and higher morbidity and mortality. Preventing macro- and micronutrient deficiency is crucial and this could be achieved through supplementation and food-based approaches.

A next generation sequencing gene panel for use in the diagnosis of anorexia nervosa

PURPOSE

The aim of this study was to increase knowledge of genes associated with anorexia nervosa (AN) and their diagnostic offer, using a next generation sequencing (NGS) panel for the identification of genetic variants. The rationale underlying this test is that we first analyze the genes associated with syndromic forms of AN, then genes that were found to carry rare variants in AN patients who had undergone segregation analysis, and finally candidate genes intervening in the same molecular pathways or identified by GWAS or in mouse models.

METHODS

We developed an NGS gene panel and used it to screen 68 Italian AN patients (63 females, 5 males). The panel included 162 genes. Family segregation study was conducted on available relatives of probands who reported significant genetic variants.

RESULTS

In our analysis, we found potentially deleterious variants in 2 genes (PDE11A and SLC25A13) associated with syndromic forms of anorexia and predicted deleterious variants in the following 12 genes: CD36, CACNA1C, DRD4, EPHX2, ESR1, GRIN2A, GRIN3B, LRP2, NPY4R, PTGS2, PTPN22 and SGPP2. Furthermore, by Sanger sequencing of the promoter region of NNAT, we confirmed the involvement of this gene in the pathogenesis of AN. Family segregation studies further strengthened the possible causative role of CACNA1C, DRD4, GRIN2A, PTGS2, SGPP2, SLC25A13 and NNAT genes in AN etiology.

CONCLUSION

The major finding of our study is the confirmation of the involvement of the NNAT gene in the pathogenesis of AN; furthermore, this study suggests that NGS-based testing can play an important role in the diagnostic evaluation of AN, excluding syndromic forms and increasing knowledge of the genetic etiology of AN.

LEVEL OF EVIDENCE

Level I, experimental study.

Molecular Alterations of the Endocannabinoid System in Psychiatric Disorders

The therapeutic benefits of the current medications for patients with psychiatric disorders contrast with a great variety of adverse effects. The endocannabinoid system (ECS) components have gained high interest as potential new targets for treating psychiatry diseases because of their neuromodulator role, which is essential to understanding the regulation of many brain functions. This article reviewed the molecular alterations in ECS occurring in different psychiatric conditions. The methods used to identify alterations in the ECS were also described. We used a translational approach. The animal models reproducing some behavioral and/or neurochemical aspects of psychiatric disorders and the molecular alterations in clinical studies in post-mortem brain tissue or peripheral tissues were analyzed. This article reviewed the most relevant ECS changes in prevalent psychiatric diseases such as mood disorders, schizophrenia, autism, attentional deficit, eating disorders (ED), and addiction. The review concludes that clinical research studies are urgently needed for two different purposes: (1) To identify alterations of the ECS components potentially useful as new biomarkers relating to a specific disease or condition, and (2) to design new therapeutic targets based on the specific alterations found to improve the pharmacological treatment in psychiatry.

Association Between DRD2 and DRD4 Polymorphisms and Eating Disorders in an Italian Population

Anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED) are the three most common eating disorders (EDs). Their etiopathogenesis is multifactorial where both the environmental and genetic factors contribute to the disease outcome and severity. Several polymorphisms in genes involved in the dopaminergic pathways seem to be relevant in the susceptibility to EDs, but their role has not been fully elucidated yet. In this study, we have analyzed the association between selected common polymorphisms in the DRD2 and DRD4 genes in a large cohort of Italian patients affected by AN (n = 332), BN (n = 122), and BED (n = 132) compared to healthy controls (CTRs) (n = 172). Allelic and genotypic frequencies have been also correlated with the main psychopathological and clinical comorbidities often observed in patients. Our results showed significant associations of the DRD2-rs6277 single nucleotide polymorphism (SNP) with AN and BN, of the DRD4-rs936461 SNP with BN and BED and of DRD4 120-bp tandem repeat (TR) polymorphism (SS plus LS genotypes) with BED susceptibility. Moreover, genotyping of DRD4 48-bp variable number TR (VNTR) identified the presence of ≥7R alleles as risk factors to develop each type of EDs. The study also showed that ED subjects with a history of drugs abuse were characterized by a significantly higher frequency of the DRD4 rs1800955 TT genotype and DRD4 120-bp TR short-allele. Our findings suggest that specific combinations of variants in the DRD2 and DRD4 genes are predisposing factors not only for EDs but also for some psychopathological features often coupled specifically to AN, BN, and BED. Further functional research studies are needed to better clarify the complex role of these proteins and to develop novel therapeutic compounds based on dopamine modulation.

Epigenetics of functional hypothalamic amenorrhea

Functional hypothalamic amenorrhea (FHA) is a temporary infertility characterized by the suppression of the hypothalamic-pituitary-gonadal (HPG) axis, induced by the inhibition of the hypothalamic pulsatile secretion of the gonadotropin-releasing hormone (GnRH), in the presence of stressors, including eating disorders, excessive exercise, and psychological distress. Although the stressful factors that may lead to FHA are well-established, little is known about the inter-individual variability in response to stress and the consequent inhibition of the HPG axis. Not all women, indeed, manifest FHA in presence of stressful conditions. Recent studies highlighted a genetic contribution to FHA. Rare or polymorphic variants in genes that control the development and/or function of GnRH neurons may contribute, indeed, to the adaptability of the reproductive axis to stress factors. Also epigenetic changes have been associated with different pathways involved in the HPG axis and therefore, take part in FHA and confer a personal predisposition to anovulation consequent to a stressful event, or represent biological markers of response to stress. This review summarizes recent advances in the identification of the contribution of (epi)genetics to FHA and to long-term complications of functional amenorrhea, and reports insights into the involvement of additional genetic loci in FHA development on the bases of the clinical and molecular overlap with other gynecological and/or psychological conditions. Finally, we describe the promising application of induced pluripotent stem cells (iPSCs) as a new approach to investigate the molecular pathways involved in FHA.

Predictors of Nutritional Status, Depression, Internet Addiction, Facebook Addiction, and Tobacco Smoking Among Women With Eating Disorders in Spain

Eating disorders (EDs) are a complex group of psychiatric conditions that involve dysfunctional eating patterns, nutritional alterations, and other comorbid psychopathologies. Some women with EDs may develop problematic internet use while they attempt to get information on dieting/weight control or get online support from people with similar problems. They may also drift toward tobacco smoking as a method to regulate their weight or to cope with their weight-related dysphoria. The occurrence of these conditions in EDs may prolong disease course and impede recovery. This study used structural equation modeling to investigate nutritional status (noted by body mass index, BMI), depression psychopathology, internet addiction (depicted by the Internet Addiction Test), Facebook addiction (depicted by the Bergen Facebook Addiction Scale), and smoking among 123 Spanish women diagnosed with EDs (mean age = 27.3 ± 10.6 years). History of hospitalization, marital status, age, and the level of education predicted BMI in certain ED groups. BMI did not predict depression, but it predicted internet addiction, Facebook addiction, and smoking in certain ED groups. Depression did not predict BMI, internet/Facebook addition, or smoking in any ED group. Some sociodemographic and clinical variables had indirect effects on depression, internet addiction, and Facebook addiction while age was the only variable expressing a direct effect on all outcome measures. Age, education, and history of prolonged treatment predicted smoking in certain ED patients. The findings signify that a considerable target for interventional strategies addressing nutritional and addictive problems in EDs would be women with high BMI, history of hospitalization, history of prolonged treatment, who are particularly young, single, and less educated. Replication studies in larger samples, which comprise various subtypes of EDs from both genders, are warranted to define the exact interaction among the addressed variables.

Vitamin D3 as possible diagnostic marker of Eating Disorders

Purpose

Eating Disorders (EDs) refer to a group of psychiatric conditions in which disorderly food intake results in impaired psychological functioning or physical health. Nowadays, these disorders represent an increasing problem in modern society. There are no universally validated clinical parameters to confirm, disprove or simply help to identify EDs except for diagnostic criteria on psychiatric basis. The aim of this study was the assessment of Vitamin D3 level in patients with EDs to understand if it might be a valid clinical biochemistry parameter useful as prognostic marker.

Methods

The sample consists of 28 female patients, who suffer from EDs. Blood samples were examined in terms of blood count, glucose, cholesterol and Vitamin D3 levels. The other clinical biochemistry parameters were analysed to understand if the Vitamin D3 was the only altered parameter.

Results

The parameters that appear altered are glycemia, cholesterol and, in particular, Vitamin D3. Significant results were obtained comparing controls with restrictive-type anorexia nervosa (p value= 0,003) and with purging-type anorexia nervosa (p value= 0,007).

Conclusion

There are currently no universally validated and diagnostic reliable clinical biochemistry parameters for EDs but, in the light of the findings, but our research indicates the potential use of Vitamin D3 as a biomarker for anorexia nervosa.

Level of evidence

Level III: Evidence obtained from a single-center cohort study.

Genetic contributions to the etiology of anorexia nervosa: New perspectives in molecular diagnosis and treatment

BACKGROUND

Anorexia nervosa is a multifactorial eating disorder that manifests with self-starvation, extreme anxiety, hyperactivity, and amenorrhea. Long-term effects include organ failure, disability, and in extreme cases, even death.

METHODS

Through a literature search, here we summarize what is known about the molecular etiology of anorexia nervosa and propose genetic testing for this condition.

RESULTS

Anorexia nervosa often has a familial background and shows strong heritability. Various genetic studies along with genome-wide association studies have identified several genetic loci involved in molecular pathways that might lead to anorexia.

CONCLUSION

Anorexia nervosa is an eating disorder with a strong genetic component that contributes to its etiology. Various genetic approaches might help in the molecular diagnosis of this disease and in devising novel therapeutic options.