Water intake and risk of hyponatraemia in Prader-Willi syndrome.

BACKGROUND AND METHODS: Unusual water intake and drinking behaviour has occasionally been observed in individuals with Prader-Willi syndrome (PWS). The aim of this study is to explore whether this observation is a part of the PWS phenotype and what the consequences may be. The parents of 51 individuals with PWS (age range 2-40 years) were asked by questionnaire to answer on past and present water intake, drinking behaviour, fluid preferences and medical treatment in their PWS-affected and unaffected children. Questionnaires with information on 47 PWS individuals and 17 without PWS were returned for analysis. The questionnaire information was complemented with information from the individual's medical records. Siblings to PWS individuals made up the control group. The study was approved by the regional medical research ethics committee. RESULTS: During infancy, 36 (76%) individuals with PWS disliked water without any flavouring and had an extremely small daily intake of water. Seven individuals (15%) increased the daily water intake to unusually high amounts. In 45 the clinical PWS diagnosis was confirmed by molecular (genetic) testing: nine of them with a confirmed PWS diagnosis had a deletion of chromosome 15q11-13, in nine individuals no deletion was identified. The majority of individuals who increased their water consumption to extreme values belonged to the non-deletion group. Two in the non-deletion group developed hyponatraemia while receiving psychiatric medication. CONCLUSIONS: Infants with PWS seem to be predisposed to unusual drinking behaviour. They dislike and have an unusually small intake of pure water without flavouring, and most of them continue this even after infancy. Some individuals, especially those without deletion, increase their fluid intake and also accept pure water. They have an increased risk of developing water retention and severe hyponatraemia if exposed to medication known to cause side effects like the syndrome of inappropriate antidiuretic hormone secretion. Perhaps this behaviour is just secondary to overeating; perhaps it is a result of a dysfunction of the hypothalamic nuclei engaged in antidiuretic hormone production.

Behavior and personality characteristics of children and young adults with Prader-Willi syndrome: a controlled study.

OBJECTIVE: To analyze (1) which behavior and personality characteristics in Prader-Willi syndrome (PWS) are primarily linked to the syndrome and not to mental retardation or being overweight, (2) how early in life such traits appear, and (3) whether current therapies affect behavior. METHOD: Parents of a group of 44 individuals with PWS and of a comparison group were interviewed and completed questionnaires about their children's behavior and personality. RESULTS: Individuals with PWS had more behavior problems than those in the comparison group. Some behaviors were specific to PWS. Younger PWS cases had fewer behavior problems than older PWS cases. Treated individuals had approximately the same degree of behavior problems as those untreated, even though a few symptoms occurred at lower rates. CONCLUSIONS: PWS is associated with behavior correlates that are not related to weight or IQ. In the first few years of life, children with PWS do not demonstrate the characteristic profile of preoccupation with food, ritualism, irritability, temper tantrums, and skin-picking which is typical of older individuals with PWS. Current therapies (including treatment with growth hormone) do not seem to radically affect the behavioral expression of the disorder, even though some problems tended to abate with treatment.

Cerebrospinal fluid monoamines in Prader-Willi syndrome.

BACKGROUND: The behavioral phenotype of Prader-Willi syndrome (PWS) suggests hypothalamic dysfunction and altered neurotransmitter regulation. The purpose of this study was to examine whether there was any difference in the concentrations of monoamine metabolites in the cerebrospinal fluid (CSF) in PWS and non-PWS comparison cases. METHODS: The concentration of monoamine metabolites in CSF was determined in 13 children and adolescents with PWS diagnosed on clinical and genetic criteria. The concentrations were compared with those from 56 comparison cases in healthy and other contrast groups. RESULTS: The concentrations of dopamine and particularly serotonin metabolites were increased in the PWS group. The differences were most prominent for 5-hydroxyindoleacetic acid. The increased concentrations were found in all PWS cases independently of age, body mass index, and level of mental retardation. CONCLUSIONS: The findings implicate dysfunction of the serotonergic system and possibly also of the dopamine system in PWS individuals, and might help inform future psychopharmacologic studies.

Is monoamine oxidase activity elevated in Prader-Willi syndrome?

The platelet contents of monoamine oxidase (MAO-B) were analyzed in 17 children and young adults with Prader-Willi syndrome and 18 non-PWS comparison cases. MAO-B activity was significantly higher in the former group, suggesting monoamine dysfunction in Prader-Willi syndrome.

Voice, speech and language characteristics of children with Prader-Willi syndrome.

Eleven individuals with Prader-Willi syndrome (PWS), aged between 4 and 25 years, were compared with II non-PWS children of the same sex, age, body mass index and IQ level. Voice, speech and language skills were generally impaired in subjects with PWS. Oral motor function, pitch level and resonance were specifically disordered and clearly differentiated the two groups from each other. Certain biological perinatal factors separated subjects with PWS from other obese children and adolescents, but did not differentiate within the group with PWS and could not account for the speech/language problems. Underlying cerebral dysfunction, combined with a characteristic anatomy of the mouth and larynx in PWS, contributes to altered voice, speech and language function.

Parental exposure to hydrocarbons in Prader-Willi syndrome.

The purpose of this study was to ascertain whether parental age and parental pre-conceptional exposure to various agents differentiated children with Prader-Willi syndrome (PWS) from obese children without PWS. Two groups of patients under 25 years of age were studied, 15 persons with PWS, and 13 with PWS-like symptoms. In the PWS group deletions were detected on chromosome 15q11-q13 and parents were older. The parents' occupational and recreational exposure to environmental toxins was recorded and correlated to the clinical diagnosis, genetics and behaviour characteristics. Paternal exposure to gasoline/petrol was significantly higher in the PWS group and is suggested as a possible important factor in the aetiology of PWS.

Hypomelanosis of Ito in three cases with autism and autistic-like conditions.

Two girls and a boy showing autistic behaviour and fulfilling the criteria for autistic disorder, Asperger syndrome or atypical autism were diagnosed as having hypomelanosis of Ito syndrome. It is suggested that skin changes indicating underlying neurocutaneous disorders be meticulously looked for in all cases with autism and autistic-like conditions.

Prader-Willi syndrome in a Swedish rural county: epidemiological aspects.

The total population under 25 years of age in one rural county in Sweden was screened in an attempt to find all cases of Prader-Willi syndrome and to establish prevalence rates for the disorder. 11 clear and five suspect cases were found. For the seven- to 25-year-old age-group the prevalence was 13 per 100,000 for clear cases only, but 20 per 100,000 if borderline cases were included. There was a slight over-representation of males, but it was possible that this was a result of under-representation of females in the very young age-groups, in whom hypogonadism may be difficult to diagnose.