Obsessions and compulsions in Prader-Willi syndrome

Prader-Willi Syndrome: Obesity due to Genomic Imprinting

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder due to errors in genomic imprinting with loss of imprinted genes that are paternally expressed from the chromosome 15q11-q13 region. Approximately 70% of individuals with PWS have a de novo deletion of the paternally derived 15q11-q13 region in which there are two subtypes (i.e., larger Type I or smaller Type II), maternal disomy 15 (both 15s from the mother) in about 25% of cases, and the remaining subjects have either defects in the imprinting center controlling the activity of imprinted genes or due to other chromosome 15 rearrangements. PWS is characterized by a particular facial appearance, infantile hypotonia, a poor suck and feeding difficulties, hypogonadism and hypogenitalism in both sexes, short stature and small hands and feet due to growth hormone deficiency, mild learning and behavioral problems (e.g., skin picking, temper tantrums) and hyperphagia leading to early childhood obesity. Obesity is a significant health problem, if uncontrolled. PWS is considered the most common known genetic cause of morbid obesity in children. The chromosome 15q11-q13 region contains approximately 100 genes and transcripts in which about 10 are imprinted and paternally expressed. This region can be divided into four groups: 1) a proximal non-imprinted region; 2) a PWS paternal-only expressed region containing protein-coding and non-coding genes; 3) an Angelman syndrome region containing maternally expressed genes and 4) a distal non-imprinted region. This review summarizes the current understanding of the genetic causes, the natural history and clinical presentation of individuals with PWS.

Development and preliminary psychometric evaluation of the Children's Saving Inventory

This study reports on the development and initial psychometric properties of the Children's Saving Inventory (CSI), a parent-rated measure designed to assess child hoarding behaviors. Subjects included 123 children and adolescents diagnosed with primary Obsessive-Compulsive Disorder (OCD) and their parents. Trained clinicians administered the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), items assessing Family Accommodation and the Clinical Global Impressions--Severity index. Parents completed the CSI, Child Obsessive-Compulsive Impact Scale (COIS)--Parent Version and Child Behavior Checklist. Youth completed the COIS--Child Version, Obsessive-Compulsive Inventory Child Version (OCI-CV), Multidimensional Anxiety Scale for Children, and Children's Depression Inventory--Short Form. A four factor solution was identified; factors were named Discarding, Clutter, Acquisition, and Distress/Impairment. Internal consistency for the CSI Total and factor scores were good. One-week test-retest reliability (n = 31) from a random subsample was excellent. Known groups validity was supported vis-à-vis higher CSI scores for those endorsing hoarding on the CY-BOCS Symptom Checklist. Convergent and discriminant validity was evidenced by weak relationships with OCI-CV Checking and Contamination factors but strong relationships with the OCI-CV Hoarding factor and with hoarding obsession/compulsions on the CY-BOCS. These findings provide initial support for the reliability and validity of the CSI for the assessment of hoarding behaviors among youth with OCD. Future studies are needed to extend these findings to non-OCD samples of youth.

Compulsive hoarding in children

This article discusses the nature and treatment of compulsive hoarding among children. We summarize the phenomenology of compulsive hoarding, including its clinical presentation, comorbidity with varied mental disorders, and associated impairment. The limited data on treatment outcome are presented along with a behavioral framework that we utilized to treat youth who hoard. Our approach is highlighted in the context of a case illustration of an 11-year-old girl suffering from compulsive hoarding and several comorbid mental health disorders. We conclude with recommendations for clinical work with this challenging and neglected population.

Behavioral phenotype in adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterized by temper tantrums, impulsivity, mood fluctuations, difficulty with change in routine, skinpicking, stubbornness and aggression. Many studies on behavior in PWS are limited by sample size, age range, a lack of genetically confirmed diagnosis of PWS and inconsistent assessment of behavior. The aim of this study was to explore systematically the relation between behavioral problems and age groups, genetic subtypes and BMI categories in an adult PWS population. Participants were contacted via the Dutch Prader-Willi Parent Association and through physicians specialized in persons with ID. Behaviors were studied using the Developmental Behavior Checklist for Adults (DBC-A). The forms were completed by the main caregivers of 98 adults with a genetically confirmed diagnosis of PWS. Differences between age groups were statistically significant (ANOVA, p=0.03). DBC-A total scores were higher in the consecutive age groups, with the most behavioral problems in the oldest age groups. Differences between genetic subtypes were also statistically significant (ANOVA, p<0.01). Persons with mUPD had higher total scores on the DBC-A than persons with a deletion. Those with a Type I deletion showed higher total DBC-A scores than persons with a Type II deletion. There were no statistically significant differences in DBC-A total scores between the different BMI categories. Individuals with a BMI<25 had higher scores on the self-absorbed subscale compared to persons with a BMI between 25 and 30. Unlike previous descriptions of the behavioral phenotype in adults with PWS, we did not find a reduction in behavioral problems in older adults. Therefore, special attention should be paid to behavioral problems as part of general management of adults with PWS. Longitudinal studies are warranted to gain more insight into the natural history and course of behavioral problems in adults and older people with PWS over the long term and possible risk and preventive factors.

Neurobehavioral phenotype in Prader-Willi syndrome

The focus of this article is on the lifetime development of people with Prader-Willi syndrome (PWS) and specifically on the neurobehavioral phenotype. We consider studies of this aspect of the phenotype (the "behavioral phenotype" of the syndrome) that have confirmed that there are specific behaviors and psychiatric disorders, the propensities to which are increased in those with PWS, and cannot be accounted for by other variables such as IQ or adaptive behavior. Beginning with a description of what is observed in people with PWS, we review the evolving PWS phenotype and consider how some aspects of the phenotype might be best explained, and how this complex phenotype may relate to the equally complex genotype. We then consider in more detail some of the neurobehavioral aspects of the phenotype listed above that raise the greatest management problems for parents and carers.

A preliminary analysis of the phenomenology of skin-picking in Prader-Willi syndrome

To examine the nature and psychosocial correlates of skin-picking behavior in youth with Prader-Willi Syndrome (PWS). Parents of 67 youth (aged 5-19 years) with PWS were recruited to complete an internet-based survey that included measures of: skin-picking behaviors, the automatic and/or focused nature of skin-picking, severity of skin-picking symptoms, anxiety symptoms, developmental functioning, symptoms of inattention, impulsivity, and oppositionality, and quality of life. Results indicated that skin-picking was endorsed in 95.5% of youth. Direct associations of moderate strength were found between skin-picking severity and symptoms of anxiety, inattention, oppositionality, developmental functioning, and quality of life. Other descriptive data, such as areas picked, cutaneous factors, antecedents, and consequences related to skin-picking are reported. The prevalence and consequences associated with skin-picking in PWS indicate a greater need for clinician awareness of the behavior and interventions tailored to meet the needs of this population.

Search for copy number variants in chromosomes 15q11-q13 and 22q11.2 in obsessive compulsive disorder

Background

Obsessive-compulsive disorder (OCD) is a clinically and etiologically heterogeneous syndrome. The high frequency of obsessive-compulsive symptoms reported in subjects with the 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) or Prader-Willi syndrome (15q11-13 deletion of the paternally derived chromosome), suggests that gene dosage effects in these chromosomal regions could increase risk for OCD. Therefore, the aim of this study was to search for microrearrangements in these two regions in OCD patients.

Methods

We screened the 15q11-13 and 22q11.2 chromosomal regions for genomic imbalances in 236 patients with OCD using multiplex ligation-dependent probe amplification (MLPA).

Results

No deletions or duplications involving 15q11-13 or 22q11.2 were identified in our patients.

Conclusions

Our results suggest that deletions/duplications of chromosomes 15q11-13 and 22q11.2 are rare in OCD. Despite the negative findings in these two regions, the search for copy number variants in OCD using genome-wide array-based methods is a highly promising approach to identify genes of etiologic importance in the development of OCD.

Clinical management of behavioral characteristics of Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder caused by an abnormality on the long arm of chromosome 15 (q11-q13) that results in a host of phenotypic characteristics, dominated primarily by hyperphagia and insatiable appetite. Characteristic behavioral disturbances in PWS include excessive interest in food, skin picking, difficulty with a change in routine, temper tantrums, obsessive and compulsive behaviors, and mood fluctuations. Individuals with PWS typically have intellectual disabilities (borderline to mild/moderate mental retardation) and exhibit a higher overall behavior disturbance compared to individuals with similar intellectual disability. Due to its multisystem disorder, family members, caregivers, physicians, dieticians, and speech-language pathologists all play an important role in the management and treatment of symptoms in an individual with PWS. This article reviews current research on behavior and cognition in PWS and discusses management guidelines for this disorder.

Psychiatric features in children with genetic syndromes: toward functional phenotypes

Neurodevelopmental disorders with identified genetic etiologies present a unique opportunity to study gene-brain-behavior connections in child psychiatry. Parsing complex human behavior into dissociable components is facilitated by examining a relatively homogenous genetic population. As children with developmental delay carry a greater burden of mental illness than the general population, familiarity with the most common genetic disorders will serve practitioners seeing a general child population. In this article basic genetic testing and 11 of the most common genetic disorders are reviewed, including the evidence base for treatment. Based on their training in child development, family systems, and multimodal treatment, child psychiatrists are well positioned to integrate cognitive, behavioral, social, psychiatric, and physical phenotypes, with a focus on functional impairment.

Is anorexia nervosa a neuropsychiatric developmental disorder? An illustrative case report

We propose the concept that anorexia nervosa is a neuropsychiatric developmental disorder. In support of the concept we present a case report of a 12-year-old girl with high functioning autistic disorder who developed Tourette syndrome and obsessive-compulsive disorder. She subsequently experienced a distinct onset of partial anorexia nervosa characterized by fear of gaining weight, body image distortions, food preference idiosyncrasies including avoidance of fat, dietary restriction, a pursuit of thinness, episodic self-induced vomiting, the missing of her menstrual cycles, and a 10% decrement in expected weight for height. She fell short of the required 15% decrement in expected weight for height to qualify for the full syndrome. Our case presentation emphasizes the longitudinal commonalities and symptomatic overlap of her multiple comorbidities. We discuss treatment approaches typically used with individuals with neuropsychiatric developmental disorders which might benefit higher functioning individuals with eating disorders. We conclude with examples of a neuropsychiatric developmental approach to generate a research agenda for anorexia nervosa.

Cognitive profile in a large French cohort of adults with Prader-Willi syndrome: differences between genotypes

BACKGROUND

Prader-Willi syndrome (PWS) is a rare genetic disorder characterised by developmental abnormalities leading to somatic and psychological symptoms. These include dysmorphic features, impaired growth and sexual maturation, hyperphagia, intellectual delay, learning disabilities and maladaptive behaviours. PWS is caused by a lack of expression of maternally imprinted genes situated in the 15q11-13 chromosome region. The origin is a 'de novo' deletion in the paternal chromosome in 70% of the cases and a maternal uniparental disomy in 25%. The two main genotypes show differences, notably regarding cognitive and behavioural features, but the mechanisms are not clear. This study assessed cognitive impairment in a cohort of adults with genetically confirmed PWS, analysed their profiles of cognitive strengths and weaknesses, and compared the profiles in terms of genotype.

METHODS

Ninety-nine male and female adults participated, all inpatients on a specialised unit for the multidisciplinary care of PWS. The Wechsler Adult Intelligence Scale (WAIS-III) was administered to all patients in identical conditions by the same psychologist. Eighty-five patients were able to cope with the test situation. Their scores were analysed with non-parametric statistical tools. The correlations with sex, age and body mass index were explored. Two genotype groups were compared: deletion (n = 57) and non-deletion (n = 27).

RESULTS

The distribution of intelligence quotients in the total cohort was non-normal, with the following values (medians): Full Scale Intelligence Quotient (FSIQ): 52.0 (Q1:46.0; Q3:60.0), Verbal Intellectual Quotient (VIQ): 53.0 (Q1:48; Q3:62) and Performance Intellectual Quotient (PIQ): 52.5 (Q1:48; Q3:61). No correlation was found with sex, age or body mass index. Comparison between groups showed no significant difference in FSIQ or VIQ. PIQ scores were significantly better in the deletion group. The total cohort and the deletion group showed the VIQ = PIQ profile, whereas VIQ > PIQ was observed in the non-deletion group. The subtest scores in the two groups showed significant differences, with the deletion group scoring better in three subtests: object assembly, picture arrangement and digit symbol coding. Some relative strengths and weaknesses concerned the total cohort, but others concerned only one genotype.

DISCUSSION

We documented a global impairment in the intellectual abilities of a large sample of French PWS patients. The scores were slightly lower than those reported in most other studies. Our data confirmed the previously published differences in the cognitive profiles of the two main PWS genotypes and offer new evidence to support this hypothesis. These results could guide future neuropsychological studies to determine the cognitive processing in PWS. This knowledge is essential to improve our understanding of gene-brain-behaviour relationships and to open new perspectives on therapeutic and educational programmes.

Clinical and genetic analysis for four Chinese families with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex, genetic, multisystem disorder. Its major clinical features include neonatal hypotonia and failure to thrive, mental retardation, hypogonadism, short hands and feet, hyperphagia-caused obesity, and characteristic appearance. The genetic basis of PWS is also complex. It is caused by the absence of expression of the active paternal genes such as the SNRPN, NDN, and possibly others in the PWS critical region on 15q11-13. PWS is in effect a contiguous gene syndrome resulting from deletion of the paternal copies of the imprinted. Consensus in clinical diagnostic criteria was established in 1993. However, identifying relevant patients for tests remains a challenge for most practitioners, as many features of the disorder are nonspecific, and others can be subtle or evolved over time. Consequently, molecular genetic tests can be used to diagnose PWS accurately, allowing early diagnosis of the syndrome. High resolution G-banding, high resolution cytogenetic methylation-specific PCR (MS-PCR), and fluorescence in situ hybridization (FISH) are routinely used to diagnose PWS. In this study, four Chinese patients, with typical PWS features, were detected by MS-PCR and FISH. Three were cytogenetically normal, but lacked paternal expression of proximal chromosome 15q because of maternal uniparental disomy (UPD). The other one, however, demonstrated an unbalanced de novo translocation 46, XX, t (7; 15).

The pathophysiology of restricted repetitive behavior

Restricted, repetitive behaviors (RRBs) are heterogeneous ranging from stereotypic body movements to rituals to restricted interests. RRBs are most strongly associated with autism but occur in a number of other clinical disorders as well as in typical development. There does not seem to be a category of RRB that is unique or specific to autism and RRB does not seem to be robustly correlated with specific cognitive, sensory or motor abnormalities in autism. Despite its clinical significance, little is known about the pathophysiology of RRB. Both clinical and animal models studies link repetitive behaviors to genetic mutations and a number of specific genetic syndromes have RRBs as part of the clinical phenotype. Genetic risk factors may interact with experiential factors resulting in the extremes in repetitive behavior phenotypic expression that characterize autism. Few studies of individuals with autism have correlated MRI findings and RRBs and no attempt has been made to associate RRB and post-mortem tissue findings. Available clinical and animal models data indicate functional and structural alterations in cortical-basal ganglia circuitry in the expression of RRB, however. Our own studies point to reduced activity of the indirect basal ganglia pathway being associated with high levels of repetitive behavior in an animal model. These findings, if generalizable, suggest specific therapeutic targets. These, and perhaps other, perturbations to cortical basal ganglia circuitry are mediated by specific molecular mechanisms (e.g., altered gene expression) that result in long-term, experience-dependent neuroadaptations that initiate and maintain repetitive behavior. A great deal more research is needed to uncover such mechanisms. Work in areas such as substance abuse, OCD, Tourette syndrome, Parkinson's disease, and dementias promise to provide findings critical for identifying neurobiological mechanisms relevant to RRB in autism. Moreover, basic research in areas such as birdsong, habit formation, and procedural learning may provide additional, much needed clues. Understanding the pathophysioloy of repetitive behavior will be critical to identifying novel therapeutic targets and strategies for individuals with autism.

The prevalence and phenomenology of repetitive behavior in genetic syndromes

We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat (N = 58), Fragile X (N = 191), Prader-Willi (N = 189), Lowe (N = 56) and Smith-Magenis (N = 42) syndromes and individuals with intellectual disability of heterogeneous aetiology (N = 56). Repetitive behavior was variable across syndromes. Fragile X syndrome scored highly on all subscales. Angelman syndrome demonstrated a significantly lowered probability for most behaviors. Prader-Willi, Cri-du-Chat and Smith-Magenis syndrome evidenced unique profiles of repetitive behavior. There is extreme heterogeneity of repetitive behavior across genetic syndromes, highlighting syndrome specific profiles.

Strategies and Correlates of Jigsaw Puzzle and Visuospatial Performance by Persons With Prader-Willi Syndrome

Some individuals with Prader-Willi syndrome exhibit strengths in solving jigsaw puzzles. We compared visuospatial ability and jigsaw puzzle performance and strategies of 26 persons with Prader-Willi syndrome and 26 MA-matched typically developing controls. Individuals with Prader-Willi syndrome relied on piece shape. Those in the control group used a different, picture-focused strategy. Individuals with Prader-Willi syndrome performed better than did the control group on an achromatic interlocking puzzle, whereas scores on puzzles with pictures (interlocking or noninterlocking) did not differ. Visuospatial scores related to performance on all puzzles in the control group and on the noninterlocking puzzle in the Prader-Willi syndrome group. The most proficient jigsaw puzzlers with Prader-Willi syndrome tended to be older and have shape-based strategies.

Frontal behavioral syndromes in Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a genetically determined neurodevelopmental disorder presenting with behavioral problems including hyperphagia, emotional aberration, and compulsion-like behaviors. This combination of behavioral problems is likely to be caused by damage to the orbitofrontal cortices and anterior temporal lobes or to circuits involving them.

OBJECTIVES

To investigate the prevalence of eating and non-eating behavioral disturbances in PWS by using assessment tools developed originally for patients with frontotemporal dementia and with frontal lobe injury.

METHOD

The questionnaire consisted of 35 questions related to three categories of behavior: eating behaviors (including four domains: appetite, food preference, eating habits, and other oral behaviors), stereotypy (including four domains: roaming, speaking, movements, and daily rhythm), and collecting behaviors. It was administered in Japan to the parents of 250 individuals aged 1-42 years with a clinical diagnosis of PWS.

RESULTS

The prevalence rates of symptoms in all categories were high. Each domain involved in eating behaviors was significantly correlated with stereotypy and collecting behaviors. The prevalence rates and severity scores of some eating and non-eating behaviors were higher in the older groups.

CONCLUSION

Abnormal eating behaviors, stereotyped behaviors, and collecting behaviors were common in the PWS subjects. There was also a potential link between abnormal eating and non-eating behaviors related to frontal behavioral syndromes. It is likely that these behavioral abnormalities reflect dysfunction of the orbitofrontal cortices and anterior temporal lobes.

Behavioral and psychiatric disorders in Prader-Willi syndrome: a population study in Japan

Prader-Willi syndrome (PWS) is a genetically determined neurodevelopmental disorder characterized by mental retardation and distinct physical, behavioral, and psychiatric features. Based on parents' questionnaires, we examined the prevalence of behavioral and psychiatric disorders of 165 persons with PWS aged 2-31 years in Japan. The data were analyzed comparing four different age groups with PWS: group 1, 2-5 years (n=34); group 2, 6-11 years (n=57); group 3, 12-17 years (n=45); and group 4, 18-31 years (n=29). Further, we compared the results of our PWS group 4 with those of 42 age-, gender-, and intelligence level-matched intellectual disability (ID) individuals without PWS. Our results showed that repetitive speech and stubbornness were prominent from early childhood and other behavioral problems such as hyperphagia, stealing food, temper tantrums, lying, and emotional lability tended to be more frequent with age among persons with PWS. Moreover, young adults with PWS have significantly higher rates of behavioral and psychiatric disorders than IDs without PWS, such as stubbornness, hyperphagia, temper tantrums, self-injurious behavior (skin picking), hypersomnia, inactivity, and delusion. Degree of obesity was not necessarily related to behavioral and psychiatric features associated with PWS. Our findings revealed that persons with PWS are more vulnerable to behavioral and psychiatric disorders particularly in young adulthood compared to those with ID from other etiologies in Japan.

Prader-Willi syndrome: an update and review for the primary pediatrician

Prader-Willi syndrome, the first known human genomic imprinting disorder, is one of the most common micro-deletion syndromes. Prader-Willi syndrome is caused by the absence of certain paternally inherited genes on the long arm of chromosome 15, resulting in a complete absence of the active copy of the genetic information in this region. It is most commonly known for its food-related characteristics of hyperphagia, food-seeking behavior, and consequent obesity. Primary care physicians play an important role in the care of children with Prader-Willi syndrome, from recognizing the presenting signs and symptoms at its various stages to understanding their unique medical, developmental, behavioral, and dietary issues. They can also serve as a valuable source of support and advocacy for the family. This article reviews the current state of knowledge about Prader-Willi syndrome and discusses up-to-date understanding of the management of this condition.

Clinical features of children and adolescents with obsessive-compulsive disorder and hoarding symptoms

OBJECTIVE

This study was conducted to examine whether pediatric patients with obsessive-compulsive disorder (OCD) and hoarding symptoms differed in terms of clinical characteristics from pediatric OCD patients without hoarding symptoms.

METHOD

Eighty children and adolescents with OCD (range, 7-17 years) completed clinician-administered and parent- and child-report measures of OCD symptom severity, impairment, and emotional and behavioral symptoms.

RESULTS

Twenty-one youth endorsed significant hoarding symptoms. Relative to nonhoarders, youth with hoarding symptoms had worse insight, more magical thinking obsessions, and ordering/arranging compulsions than nonhoarders, higher levels of anxiety, aggression, somatic complaints, and overall externalizing and internalizing symptoms. Higher rates of panic disorder were found in youth with hoarding symptoms although other comorbidity rates did not differ.

CONCLUSIONS

These findings in children are partially consistent with studies in adults, and suggest that pediatric patients with hoarding symptoms may exhibit a unique clinical presentation.

Velocardiofacial syndrome

Velocardiofacial syndrome (VCFS) is the most common known microdeletion in humans. It is also the most common known genetic risk factor for schizophrenia. The aim of this article is to describe the clinical characteristics of the syndrome, with emphasis on the myriad psychiatric disorders and abnormal behaviors from a developmental perspective. In addition, the possible pathways that lead to the psychotic symptoms and cognitive deficits are discussed. Guidelines are suggested to alert clinicians to the possibility of the presence of VCFS, and the cumulative clinical experience and limited research on psychiatric treatments for VCFS are presented. There is an urgent need to conduct treatment trials in this high-risk population.

Social phenotypes in neurogenetic syndromes

Many of the known genetically based neurodevelopmental disorders are associated with a distinctive behavioral phenotype. As these behavioral phenotypes have been elucidated by clinical research, distinctive profiles of social traits have emerged as prominent syndromic features. This article reviews social phenotypic findings for fragile X syndrome, Down syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, Turner syndrome, Williams syndrome, and velocardiofacial syndrome. An analysis of these social profiles raises several questions regarding the relationship between identified social impairments and autism and the relationship between social impairments in neurodevelopmental disorders and those found in normative child populations. The unique profile of certain of the known behavioral phenotypes also serves to distinguish several dimensions of sociability that are not readily observed in typical populations.

Prader-Willi syndrome: medical prevention and behavioral challenges

In this article the authors discuss the genetic, medical, and endocrinologic issues of Prader-Willi syndrome and their treatment. The authors also present the typical cognitive profile characterized by specific strengths and areas of disability. The behavioral phenotype of Prader-Willi syndrome affects four domains: food-seeking related behaviors; traits that indicate lack of flexibility; oppositional behaviors, and interpersonal problems. The management of the maladaptive behaviors is challenging and requires lifelong restrictive supervision (to prevent morbid obesity), addressing psychiatric comorbidity, psychopharmacologic management exacerbated by metabolic abnormalities, ongoing medical care, and, in many cases, institutional treatment. The multiple facets of the clinical problems demand a multidisciplinary approach with anticipatory medical and psychiatric care, oriented to enhancing the quality of life of individuals who have Prader-Willi syndrome.

Assessment of hyperphagia in Prader-Willi syndrome

OBJECTIVE

Prader-Willi syndrome (PWS), the leading known genetic cause of obesity, is characterized by intellectual disabilities, maladaptive and compulsive behaviors, and hyperphagia. Although complications of obesity resulting from hyperphagia are the leading cause of death in PWS, quantifying this drive for food has long been an unmet research need. This study provides factor-analytic and within-syndrome analyses of a new measure of hyperphagia in PWS.

RESEARCH METHODS AND PROCEDURE

A 13-item informant measure, the Hyperphagia Questionnaire, was developed and administered to the parents of 153 persons with PWS, 4 to 51 years of age. The intelligence quotients, genetic subtypes of PWS, and BMIs of offspring were obtained, as were measures of their non-food problem behaviors.

RESULTS

Factor analyses with varimax rotation produced three statistically and conceptually robust factors that accounted for 59% of the variance: Hyperphagic Behaviors, Drive, and Severity. Hyperphagic Behavior increased with age, whereas Drive remained stable, and Severity dipped in older adults. Hyperphagic Drive and Severity were positively correlated with non-food behavior problems, and Hyperphagic Drive differentiated the 36% of participants with extreme obesity from those who had overweight/obese (48%) or healthy (16%) BMI classifications.

DISCUSSION

The Hyperphagia Questionnaire is a robust tool for relating breakthroughs in the neurobiology of hyperphagia to in vivo food-seeking behavior and for examining the psychological and developmental correlates of hyperphagia in PWS. The Hyperphagia Questionnaire also offers a nuanced, real-life outcome measure for future clinical trials aimed at curbing the life-threatening drive for food in PWS.

Molecular Basis of Genetic Neuropsychiatric Disorders

The past decade has seen tremendous advances in our understanding of the molecular and genetic basis of many neuropsychiatric disorders. Although the genetic aberrations that lead to these syndromes have been identified in many cases, not much is known about specific gene products and their function. This article reviews the molecular basis of well-known neurogenetic disorders. The syndromes discussed here follow a Mendelian pattern of inheritance and are predominantly single-gene disorders; however, most childhood and adolescent psychiatric disorders are polygenic in nature. This genetic complexity and heterogeneity has made it difficult to identify the genes involved in their etiology. Identification of genetic and environmental risk factors involved in the etiology of complex disorders, such as autism, will help in the discovery of medications that can ameliorate the symptoms.

The relationship between compulsive behaviour and academic achievement across the three genetic subtypes of Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a genetic syndrome associated with several physical, cognitive and behavioural characteristics. For many individuals with this syndrome, compulsive behaviour is often noted in both food and non-food situations. The focus of this paper is on the non-food-related compulsions in individuals with PWS and comparing differences across the three genetic subtypes of the syndrome.

METHODS

Compulsive behaviours in 73 people with PWS were assessed using the Yale-Brown Obsessive Compulsive Scale and the Compulsive Behavior Checklist. Compulsive behaviour and its relation to IQ and academic achievement also were evaluated. Phenotypic differences were characterized for the three most common genetic subtypes of the disorder: 16 individuals with the long Type I (TI) 15q deletion, 26 individuals with the short Type II (TII) 15q deletion and 31 individuals with maternal disomy 15.

RESULTS

There appeared to be important differences between the two deletion subtypes. Specifically, individuals with the TI deletion had more compulsions regarding personal cleanliness (i.e. excessive bathing/grooming), and their compulsions were more difficult to interrupt and interfered with social activities more than the other subtypes. Individuals with the TII deletion were more likely to have compulsions related to specific academic areas (i.e. rereading, erasing answers and counting objects or numbers).

CONCLUSIONS

These findings may help clinicians and researchers identify possible intervention strategies and supports based on the behavioural phenotype associated with genetic subtype in individuals with PWS.

Autistic-like symptomatology in Prader-Willi syndrome: a review of recent findings

Prader-Willi syndrome (PWS) is caused by either the structural loss of material or the absence of gene expression from the paternally inherited copy of chromosome 15 in the q11-q13 region. In addition to a well-described behavioral phenotype that includes hyperphagia, obsessive-compulsive symptoms, disruptive behavior, and an increased risk for mood disorders, recent evidence also suggests that some individuals with PWS have repetitive behavior and social deficits reminiscent of autism spectrum disorders. In particular, it appears as if those with maternal uniparental disomy (UPD) as the cause of PWS are at greater risk for autistic symptomatology than those with paternal deletions of 15q11-q13. These findings are particularly intriguing in light of data implicating maternal duplications and triplications of the same chromosomal interval in idiopathic autism, as well as evidence that functional alterations of genes in this region are associated with social deficits found in a variety of neurodevelopmental disorders. This paper will review the recent evidence for phenotypic similarities between autism and PWS and the risk of symptomatology for the UPD subtype.

Language development in a 3-year-old boy with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a genetic disorder which has widespread developmental consequences including motor, cognitive and language delay. Previous research on PWS children has focused primarily on phonological development and dysfluency. In the present study, the lexical development of a boy with PWS was investigated in a series of 18 play sessions recorded over a 4 month period from the ages 3;7 to 3;11. In comparison to the language development of children with Down syndrome this child with PWS appears to display a distinct developmental pattern. The possibility of detailing a behavioural phenotype of genetic disorders affecting language development is discussed.

Clinical Effects of Treatment for Hypogonadism in Male Adolescents with Prader-Labhart-Willi Syndrome

BACKGROUND

In boys with Prader-Labhart-Willi syndrome (PWS), hypogonadism causes pubertal arrest and reduces pubertal muscle growth. Formerly, it was assumed that therapy with gonadal hormones accentuates behaviour abnormalities in PWS. Our aim was to assess the clinical effects of human chorionic gonadotropin (hCG) therapy on pubertal development, muscle mass and behaviour in adolescents with PWS.

METHODS

6 peripubertal boys with PWS undergoing long-term treatment with growth hormone were examined 6-monthly for at least 2 years before and after pubertal arrest (13.5 +/- 0.3 years, mean +/- SEM) and the beginning of hCG therapy (500-1,500 IU twice weekly, intramuscularly). Height, weight, pubertal stage, bone age, body composition (by dual-energy X-ray absorptiometry), testosterone levels and behaviour abnormalities (obtained from parents) were assessed.

RESULTS

Testicular volume and lean mass were reduced in pubertal boys with PWS. During hCG therapy, testosterone levels and lean mass significantly increased (at the beginning and after 2 years of hCG therapy: 2.3 +/- 0.9 and 10.7 +/- 1.3 nmol/l, -3.1 +/- 0.3 and -1.4 +/- 0.6 SD, respectively), and fat mass stabilized at 38%. The characteristically observed PWS-associated problems, mood instability, aggressiveness and difficulties in social interaction, did not deteriorate during therapy.

CONCLUSION

In the present study, timely application of hCG to treat hypogonadism in boys with PWS promoted virilization and normalized muscle mass without detrimental effects on behaviour. Larger studies comparing hCG therapy with testosterone replacement would be useful.

Epidemiology and Etiology of Mental Retardation

Mental retardation (MR) is a manifestation of a heterogeneous set of impairments and conditions that result in cognitive limitation. It is a condition of medical, educational, and social importance. Physicians identify profound, severe, and moderate MR but rarely diagnose mild MR unless it is associated with a genetic or medical syndrome. From a medical perspective, the quest for etiology and the possibility of medical or surgical intervention to minimize deterioration are paramount. Educators, on the other hand are less concerned with causation than with academic achievement and school success. The majority of cases of mild MR is identified in school settings. Finally, the public uses the label to describe poor adaptive skills. Adults with MR who hold jobs, live independently, and participate in society are not always described as having MR. Thus some individuals characterized in childhood or adolescence as having mild MR become indistinguishable from the general population in adulthood.

Psychische Störungen bei behinderten Kindern und Jugendlichen - Übersicht und Schlussfolgerungen für die Psychodiagnostik

Zusammenfassung: Es wird eine Übersicht über die Studien zur Prävalenz psychischer Störungen bei Hörschädigung, Blindheit, körperlicher oder intellektueller Behinderung gegeben. Neben Entwicklungseinschränkungen in Folge von organischen oder genetischen Bedingungen tragen Belastungen der Eltern-Kind-Beziehung und der Entwicklung sozialer Kompetenzen sowie der sozialen Partizipation zu einem deutlich erhöhten Risiko für die Ausbildung emotionaler oder sozialer Störungen bei. Probleme der psychopathologischen Beurteilung sowie der Differenzierung zwischen Auswirkungen der Behinderung und psychischer Störung werden diskutiert und Schlussfolgerungen für die Praxis gezogen.

Between control and freedom in the care for persons with Prader-Willi syndrome: an analysis of preferred interventions by caregivers

OBJECTIVE

The present study examined caregivers' preferences for intervention strategies in dealing with the dilemma of respecting autonomy of intellectually disabled persons versus providing high-quality care.

METHODS

Twenty-four parents and 14 professional caregivers of persons with Prader-Willi syndrome were asked to rate four different kinds of intervention strategies according to their preferred way of dealing with 8 presented cases.

RESULTS

In general, caregivers preferred to intervene more actively in eating problems compared to behavioural problems, more in acute than in chronic situations, and more in situations at home than in community-based settings. Significant differences were found between parents and professionals.

CONCLUSION

Parents and professionals prefer intervening above laissez-faire. Parents prefer active intervention stronger than professionals.

PRACTICE IMPLICATIONS

Awareness of various intervention strategies can help caregivers to develop a practice that does justice to the need for intervention on the one hand, and the possibility of using a variety of intervention strategies on the other hand. Communication about intervention strategies might foster understanding between professional caregivers and parents and improve mutual cooperation.

Expression of 4 genes between chromosome 15 breakpoints 1 and 2 and behavioral outcomes in Prader-Willi syndrome

Prader-Willi syndrome is a neurodevelopmental disorder that is characterized by infantile hypotonia, feeding difficulties, hypogonadism, mental deficiency, hyperphagia (leading to obesity in early childhood), learning problems, and behavioral difficulties. A paternal 15q11-q13 deletion is found in approximately 70% of patients with Prader-Willi syndrome, approximately 25% have uniparental maternal disomy 15, and the remaining 2% to 5% have imprinting defects. The proximal deletion breakpoint in the 15q11-q13 region occurs at 1 of 2 sites located within either of 2 large duplicons allowing for the identification of 2 deletion subgroups. The larger, type I (TI) deletion involves breakpoint 1, which is close to the centromere, whereas the smaller, type II (TII) deletion involves breakpoint 2, located approximately 500 kilobases distal to breakpoint 1. Breakpoint 3 is located at the distal end of the 15q11-q13 region and common to both typical deletion subgroups. Analyses of the genetic subtypes of Prader-Willi syndrome to date have primarily compared individuals with typical deletion and uniparental maternal disomy 15 without grouping the individuals with a deletion into TI or TII. Distinct differences have been reported between individuals with Prader-Willi syndrome resulting from deletion compared with uniparental maternal disomy 15 in physical, cognitive, and behavioral parameters. We previously presented the first assessment of clinical differences in individuals with Prader-Willi syndrome categorized as having type I or II deletions. Adaptive behavior, obsessive-compulsive behaviors, reading, math, and visual-motor integration assessments were generally poorer in individuals with Prader-Willi syndrome and the TI deletion compared with subjects with Prader-Willi syndrome with the TII deletion or uniparental maternal disomy 15. Four genes (NIPA1, NIPA2, CYFIP1, and GCP5) have been identified in the chromosomal region between breakpoints 1 and 2 and are implicated in compulsive behavior and lower intellectual ability observed in individuals with Prader-Willi syndrome with TI versus TII deletions. We quantified messenger-RNA levels of these 4 genes in actively growing lymphoblastoid cells derived from 8 subjects with Prader-Willi syndrome with the TI deletion (4 males, 4 females; mean: age 25.2 +/- 8.9 years) and 9 with the TII deletion (3 males, 6 females; mean age: 19.5 +/- 5.8 years). Messenger-RNA levels were correlated with validated psychological and behavioral scales administered by trained psychologists blinded to genotype status. Messenger RNA from NIPA1, NIPA2, CYFIP1, and GCP5 was reduced but detectable in the subjects with Prader-Willi syndrome with the TI deletion, supporting biallelic expression. For the most part, messenger-RNA values were positively correlated with assessment parameters, indicating a direct relationship between messenger-RNA levels and better assessment scores, with the highest correlation for NIPA2. The coefficient of determination indicated the quantity of messenger RNA of the 4 genes explained from 24% to 99% of the variation of the behavioral and academic parameters measured. By comparison, the coefficient of determination for deletion type alone explained 5% to 50% of the variation in the assessed parameters. Understanding the influence of gene expression on behavioral and cognitive characteristics in humans is in the early stage of research development. Additional research is needed to identify the function of these genes and their interaction with gene networks to clarify the potential role they play in central nervous system development and function.

Behavioral and Emotional Symptoms of Children and Adolescents with Prader-Willi Syndrome

To examine the behavioral and emotional difficulties of 73 children and adolescents with Prader-Willi Syndrome (PWS), mental retardation-only, and dual diagnosis (i.e., mental retardation and psychiatrically disordered) on the Devereux Scales of Mental Disorders (DSMD: Naglieri, LeBuffe, & Pfeiffer, Devereux Scales of Mental Disorders (DSMD) San Antonio, TX: PsychCorp 1994). Multivariate analyses and "Italic">d-ratios were computed to assess the statistical and clinically meaningful differences between pairs of samples. The PWS sample exhibited statistically significant higher levels of psychopathology than the mentally-retarded-only sample on the Total, Externalizing, Internalizing, Attention/Delinquency, Conduct, Anxiety, and Acute Problems Scales. When compared to the dually-diagnosed sample, children with PWS Syndrome had comparable levels of psychopathology, but lower levels of depression. Results revealed that PWS represents a highly unique and complex psychological disorder with multiple areas of disturbances.

Pervasive developmental disorders in Prader-Willi syndrome: the Leuven experience in 59 subjects and controls

In the present study we investigated the co-morbidity of pervasive developmental disorder (PDD) in 59 Prader-Willi syndrome (PWS) individuals and in 59 non-specific mentally retarded controls, matched for IQ, gender, and age. The 'Pervasive Developmental Disorder Mentally Retardation Scale' (PDD-MRScale), a screening questionnaire based on the DSM-III-R criteria for PDD, has been applied in the PWS group and in the control group. Results of the present study revealed a striking autistic-like behavioral phenotype in the majority of the PWS individuals, particularly deficits in the quality of language and communication and of imagination and interests. This intersection with autistic symptomatology is an important addition to the behavioral phenotype in PWS persons. A first approach to delineate subtypes of autistic symptomalogy among PWS persons was performed. Nineteen percent of the PWS group did meet the full diagnostic DSM-III-R criteria for PDD in comparison with 15% in the control group. Results revealed that a higher IQ in PWS does not protect to develop genuine PDD and that uniparental disomy/imprinting mutation as genetic origin seems to be an additional risk factor for developing genuine PDD. The results of the present study suggest the importance of reconsidering the commonly recognized obsessive-compulsive like behavior in PWS persons within the broader spectrum of autism disorders.

Toward a positive psychology of mental retardation

Researchers and practitioners alike have long focused on the external life conditions, adaptive behavior, and inclusion of persons with mental retardation. Using breakthroughs in positive psychology, this article proposes a new research agenda focused on the positive, internal states of those with mental retardation. It shows how major movements in the mental retardation field--quality of life, dual diagnosis, personality motivation, and families--have succeeded in some arenas but failed to address happiness and well-being. Examples of happiness--of positive emotions, flow, strengths, and virtues--are offered in people with genetic causes of mental retardation. Complexities related to etiology, measurement, flow, and a meaningful life are described, as is the vital role that mental retardation can play in the emerging science of positive psychology.

Compulsive behavior in Prader-Willi syndrome: examining severity in early childhood

Prader-Willi syndrome (PWS) is a genetic disorder characterized by hyperphagia and food preoccupations. Researchers indicate that individuals with PWS, including young children, exhibit food and non-food-related compulsions. Normative rituals are also often present among typically developing preschoolers. However, it is unclear how these behaviors affect the child. Although preschoolers with PWS exhibit more types of rituals than other populations, it is uncertain if the severity of these behaviors differs from the rituals experienced during normative development. Thus, the purpose of this research was to determine whether the ritualistic behaviors exhibited by preschoolers with PWS differ in severity from those exhibited during normative development. We also sought to identify whether non-food ritualistic behavior was related to the hyperphagia in PWS. Parents of 68 children with PWS, 86 typically developing children, and 57 children with developmental delays completed questionnaires on rituals and eating behavior. Children with PWS exhibited more severe ritualistic behavior than typically developing children but not other children with developmental delays. However, the severity of non-food-related rituals was related to the severity of eating behavior in PWS. We hypothesize that this link between hyperphagia and non-food-related compulsivity may share a common underlying neurobiological mechanism.

Repetitive and ritualistic behaviour in children with Prader-Willi syndrome and children with autism

BACKGROUND

Recent research has shown that the range of repetitive behaviour seen in individuals with Prader-Willi syndrome (PWS) extends beyond food-related behaviour.

METHODS

The presence and intensity of repetitive, rigid and routinized behaviour in children with PWS was compared with that seen in children with another neurodevelopmental condition in which repetitive behaviour is common: children with autism. Parents completed the Childhood Routines Inventory (CRI).

RESULTS

Contrary to our predictions, controlling for developmental level, children with PWS and children with autism showed similar levels of repetitive and ritualistic behaviour overall and on the two CRI factors measuring 'just right' and 'repetitive' behaviour. Indeed, the majority of the sample of parents of children with PWS endorsed most items on the CRI. However there was some specificity at the level of individual items with parents of children with PWS more frequently endorsing an item on 'collecting and storing objects' and parents of children with autism more frequently endorsing 'lining up objects', 'has a strong preference for certain foods' and 'seems aware of detail at home'.

CONCLUSIONS

These findings confirm the range of repetitive behaviours that form part of the behavioural phenotype of PWS, including insistence on sameness and 'just right' behaviours, and uncover a surprising overlap with those seen in children with autism. Clinical management for children with PWS should include advice and education regarding management of repetitive and rigid behaviour. Future research should investigate whether the repetitive behaviours that form part of the behavioural phenotype of both PWS and autism are associated with a common neuropsychological, neurotransmitter or genetic origin.

A measure of food seeking in individuals with Prader-Willi syndrome

BACKGROUND

Individuals with Prader-Willi syndrome (PWS), a chromosome 15 genetic disorder, often have a significant preoccupation with food and problem behaviour related to food seeking is often prevalent.

METHODS

In the present study, we compared how individuals with PWS responded on a survey regarding the acceptability of food in various locations that varied according to degree of appropriateness for human consumption (e.g. food on a plate, food in a garbage can). For a subgroup of participants, we observed how they actually responded when placed in a room with food items placed in the same locations depicted in the survey. In the first part of the study, three groups (25 typically developing individuals, 7 individuals with intellectual disability (ID), and 19 individuals with PWS) responded to a visual survey to determine the degree of acceptability of food items in various locations (e.g. on a table near a hairbrush, on the floor behind a toy box, in a trash can). In the second part of the study, these food items (popcorn, jelly beans) were placed in the 12 locations described above. Nine individuals diagnosed with PWS (deletion type) and three individuals with ID were given some break time in the room for 15 min. The amount of food consumed, the time spent food seeking, and time spent interacting with materials were measured.

RESULTS

Results of the survey indicated that the PWS group differed significantly with regard to how they responded on the survey from the typically developing group, but did not differ significantly from the ID group. Results of the food seeking observations indicated that only three individuals with PWS ate a significant number of items. The three individuals did not differ from the rest of the group according to IQ or compulsivity score; however, they had significantly lower body mass index (BMI) scores and were younger than the other participants.

CONCLUSIONS

The findings from the survey indicate that individuals with PWS are able to discriminate the appropriateness of eating items in more or less contaminated areas; however, the amount of time spent seeking food and the amount of food covertly consumed appeared to depend more directly on age and BMI.

Autism spectrum disorders in Prader???Willi and Angelman syndromes: a systematic review

Autism spectrum disorders (ASDs) have been linked with maternally derived duplications/triplications of chromosome 15q11-13 and therefore might occur more frequently in people with Prader-Willi syndrome (PWS) when due to uniparental disomy (UPD), than in other forms of chromosomal abnormality involving this region [i.e. deletion (DEL) forms of PWS and DEL+UPD forms of Angelman's syndrome -(AS)]. Twelve studies regarding ASD in PWS and AS were reviewed. It was noteworthy that among the genetically confirmed UPD and DEL cases of PWS and AS, the rate of ASD was 25.3% (38/150; range 0-36.5%) in PWS and 1.9% in AS (2/104; range 0-100%) (Fisher's exact P<0.0001). Among the subset of cases with confirmed UPD or DEL, the rate of ASD in the UPD cases of PWS was significantly higher (20/53) than in the remaining combined samples (i.e. DEL PWS+UPD AS+DEL AS cases; 20/201) (Fisher's exact P<0.0001). ASD in UPD PWS cases (20/53) compared with DEL PWS cases (18/97) was also statistically significant (Fisher's exact P=0.0176). Thus, the limited available evidence supported the prediction that overexpression of maternally imprinted genes in 15q11-13 confers a risk for ASD. Further research will be required to confirm these findings.

Prader-Willi syndrome: clinical genetics, cytogenetics and molecular biology

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder that arises from lack of expression of paternally inherited genes known to be imprinted and located in the chromosome 15q11-q13 region. PWS is considered the most common syndromal cause of life-threatening obesity and is estimated at 1 in 10,000 to 20,000 individuals. A de novo paternally derived chromosome 15q11-q13 deletion is the cause of PWS in about 70% of cases, and maternal disomy 15 accounts for about 25% of cases. The remaining cases of PWS result either from genomic imprinting defects (microdeletions or epimutations) of the imprinting centre in the 15q11-q13 region or from chromosome 15 translocations. Here, we describe the clinical presentation of PWS, review the current understanding of causative cytogenetic and molecular genetic mechanisms, and discuss future directions for research.

ADHD symptoms and insistence on sameness in Prader-Willi syndrome

BACKGROUND

Apart from a pervasive eating disorder, the Prader-Willi (PWS) syndrome is characterized by a distinct behavioural profile comprising maladaptive behaviours, obsessive-compulsive traits and skin picking, all included in the PWS behavioural phenotype. In this study, we present a further delineation of this characteristic behavioural profile by screening for indices of executive dysfunctions related to attention-deficit/hyperactivity disorder (ADHD), immature compulsive-like adherence to sameness and skin picking, and how these features aggregate into symptom constellations in children and adolescents with PWS.

METHOD

Parents of 58 individuals with PWS (aged 5-18 years) participated by completing Childhood Routines Inventory (CRI) and Conners' Parent Rating Scale (CPRS-48).

RESULTS

Results showed that indices of ADHD and excessive insistence on sameness were common, comorbid and of early onset. They were both associated with conduct problems. Skin picking, appearing as a single and comorbid symptom, was less associated with childlike compulsions and ADHD-related problems.

CONCLUSIONS

Findings are discussed in terms of further research in executive dysfunctions in PWS.

Differences in behavioural phenotype between parental deletion and maternal uniparental disomy in Prader-Willi syndrome: an ERP study

OBJECTIVE

Paternal deletion and maternal uniparental disomy are the principal genetic subtypes associated with Prader-Willi syndrome (PWS). Recent clinical findings suggest differences in phenotype between these subtypes. The present experimental study addresses this issue using a cognitive psycho-physiological setup.

METHODS

Behaviour and event-related brain activity (ERP) was recorded by a continuous performance response inhibition task (CPT-AX) in adults with paternal deletion PWS (n=11), maternal uniparental disomy PWS (n=11) and normal controls (n=11). The dependent behavioural variables of the CPT-AX task were reaction time and correct scores. For the ERPs the N200 and P300 components were included which are related to early modality-specific inhibition and late general inhibition, respectively.

RESULTS

The disomy group had fewer correct scores and increased reaction times as compared to the CPT-AX task than the control and deletion group. Both PWS subgroups differed significantly from the control group for the N200 amplitude. Only the control group showed the typical task modulation for the N200 amplitude. The amplitude of the P300 component was considerably smaller in the uniparental disomy group than in the deletion and control groups.

CONCLUSIONS

The ERP results suggest that early modality specific inhibition is impaired in both PWS genetic subtypes. Late general inhibition is impaired in the uniparental disomy group only. Thus, although the ERP data suggests a common impairment in early visual inhibition processing, uniparental disomy and parental deletion genetic PWS subtypes clearly differ in their behavioural and brain activation phenotypes.

SIGNIFICANCE

The present study is the first experimental demonstration which explains the two principal genetic mechanisms that hinder the expression of the genes at 15q11-q13g in PWS result in different behavioural phenotype.

Cognitive, emotional, physical and social effects of growth hormone treatment in adults with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a multisystem genetic disorder characterized by short stature, muscular hypotonia, hyperphagia, obesity, maladaptive behaviour, hypogonadism and partial growth hormone (GH) deficiency (GHD). Severe GHD of other aetiologies has been shown to affect mood and quality of life negatively, and there are reports of improvements with GH replacement. We have studied cognitive, emotional, physical and social parameters in PWS adults at baseline, during and after GH treatment.

PATIENTS AND METHODS

Nineteen patients, 9 females and 10 males, median age 25 years, mean BMI 35 kg/m2 participated in this study. Approximately half of the group had GHD. All patients fulfilled the clinical criteria for PWS and 13 had a positive genotype. The patients were randomized to 6 months of treatment with either GH [1.6 IU/day (0.53 mg/day)] or placebo, followed by 12 months of active GH treatment. Treatment was then stopped, and the patients were followed for an additional period of 6 months. A test battery for general cognitive evaluation and a computer-based measurement of reaction time, motor speed and fluency were employed at baseline, after 6 months and at the end of GH treatment. At the same time intervals, a self-evaluation questionnaire was answered at the end of each test session. Other questionnaires reflecting the patients' cognitive, emotional, physical and social status were answered by relatives/caretakers at baseline and at 3 and 6 months following cessation of GH treatment.

RESULTS

Baseline cognitive level was estimated to be moderately to mildly impaired; IQ range was 40-90. The results from some of the cognitive and the motor performance tests improved significantly after 6 and 18 months of GH treatment. According to the questionnaires, both the patients and the relatives/caretakers evaluated physical status rather negatively at baseline, but still, impairments in both physical and social status and overall functioning were observed when GH treatment was discontinued. The self-evaluation did not change in any aspect during GH treatment.

CONCLUSIONS

In this pilot study of an adult PWS cohort, we were able to document beneficial effects in mental speed and flexibility and in motor performance during GH treatment. Impairment was seen in physical and social status as well as overall functioning, when GH treatment stopped. Studies of larger cohorts are needed to further elucidate the role of GH treatment in this group of patients.