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Research Notes: PWS Abstracts - 1996[ 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996 | 1995 | 1994 | 1993 | 1992 | 1991 | 1990 | 1980-1989 | 1979 and prior ] Arch Pediatr Adolesc Med. 1996 Dec. Objectives: To assess nighttime and daytime sleep patterns in patients with Prader-Willi syndrome and to examine the effects of weight change on excessive daytime sleepiness in patients with this disorder. Design: Case series (within-subject design). Setting: A university sleep disorders center. Patients: Eight patients (5 males and 3 females), ranging in age from 5.5 to 21 years, who met the diagnostic criteria for Prader-Willi syndrome. Interventions: Overnight sleep polysomnographic recording and daytime Multiple Sleep Latency Test. Four of the 8 patients were restudied after their weight had changed. Main outcome measures: Changes in the sleep disordered breathing rate and Multiple Sleep Latency Test measures. Results: Sleep-disordered breathing occurred in all patients and was principally characterized by obstructive hypoventilation or episodes of apnea that occurred primarily during rapid eye movement sleep. After weight reduction, 3 patients had respiratory values that were within the broad normal range (disordered breathing rate, < 15 breaths per hour). Statistically significant (P < .05) weight loss effects occurred during nonrapid eye movement sleep (decrease with weight loss, F = 6.243). Excessive daytime sleepiness was documented in 6 of 7 patients who completed the Multiple Sleep Latency Test. Excessive daytime sleepiness was not consistently correlated with body weight or any of the nocturnal sleep variables. Conclusions: A sleep-related breathing disorder occurred during rapid eye movement and nonrapid eye movement sleep and improved with weight change in patients with Prader-Willi syndrome, emphasizing the importance of weight reduction in clinical management. However, excessive daytime sleepiness persisted despite a reduction in sleep-disordered breathing after weight loss, suggesting a primary disturbance of sleep. Our findings provide additional support for the view that primary hypersomnia is a characteristic feature of the Prader-Willi syndrome. Metabolism. 1996 Dec. Obesity is a common component of non-insulin-dependent diabetes mellitus (NIDDM) and plays an important role in the development of insulin resistance and hyperinsulinemia. Prader-Willi syndrome (PWS) has been associated with morbid obesity and an increased propensity for early development of NIDDM. It has been assumed that the etiology for this increased rate of NIDDM is related to the morbid obesity and concomitant insulin resistance, but this remains controversial. To shed light on the glucoregulatory mechanisms in PWS, we studied both pediatric and adult PWS patients with normoglycemia. The objectives of our study were (1) to examine glucose, insulin, and C-peptide responses to oral (OGTT) and intravenous (IVGTT) glucose tolerance tests; (2) to characterize acute first- and second-phase insulin secretion during an IVGTT; (3) to assess hepatic insulin extraction (HIE) and insulin clearance (IC) in PWS subjects; and (4) to determine whether beta-cell function in PWS is age-dependent. These results in PWS were compared with values obtained in age-, sex-, and body mass index (BMI)-matched non-PWS obese controls. Three groups were studied. Group I consisted of nine PWS subjects under the age of 13 years and 22 age-, sex-, weight-, and puberty stage-matched obese subjects who underwent OGTT. Group II consisted of 14 adult PWS subjects and 10 age-, weight-, and BMI-matched obese adults who underwent OGTT. Group III consisted of nine adult PWS subjects and eight age-, sex-, and weight-matched obese adults who underwent frequently sampled IVGTT (FSIVGTT). During the OGTT in the pediatric group, fasting (86 +/- 3 v 89 +/- 2 mg/dL), peak (144 +/- 11 v 147 +/- 4 mg/dL), and total area under the curve (AUC) (6,984 +/- 1,320 v 6,963 +/- 615 mg/dL x min) glucose levels were not significantly different in PWS versus obese children, respectively. In contrast, fasting (20 +/- 6 v 37 +/- 4 microU/mL), peak (114 +/- 24 v 214 +/- 23 microU [correction of mU]/mL), and total AUC (12,673 +/- 2,176 v 26,734 +/- 2,608 microU/mL microU/mL min) insulin levels were significantly lower in pediatric PWS. During the OGTT in the adult groups, neither fasting insulin (16.7 +/- 2.8 v 13.5 +/- 2.5 microU/mL) nor total AUC for insulin (10,664 +/- 1,955 v 11,623 +/- 1,584 microU/mL x min) were significantly different in adult PWS and obese groups. During the IVGTT in adults, both first-phase (138 +/- 42 v 454 +/- 102 microU/mL x min) and second-phase (295 +/- 66 v 1,015 +/- 231 microU/mL x min) insulin release were significantly reduced in PWS subjects despite similar glucose levels. Similarly, first-phase (8.6 +/- 2.3 v 21 +/- 4.6 ng/dL x min) and second-phase (47 +/- 4.6 v 75 +/- 14 ng/dL x min) C-peptide responses were also significantly reduced in PWS subjects. In contrast, mean HIE and IC was 33% higher in PWS subjects versus obese controls (15.4 +/- 1.5 v 10.3 +/- 1.6). Similarly, poststimulation HIE and IC was significantly greater (5.2 +/- 0.8 v 2.4 +/- 0.4) in the PWS group compared with the obese group (P < .01). In summary, this study demonstrates that nondiabetic PWS subjects manifest (1) a reduced beta-cell response to glucose stimulation, (2) a significantly increased HIE compared with obese controls, and (3) a dissociation of obesity and insulin resistance, in contrast to normal obese subjects. We conclude that glucoregulatory mechanisms are different in obese PWS versus non-PWS subjects. J Endocrinol Invest. 1996 Nov. In order to evaluate the impairment of GH response in patients affected by Prader-Labhardt-Willi (PLW) syndrome, in 18 patients we studied GH response to clonidine and to GHRH + pyridostigmine, a cholinergic drug which enhances GHRH induced GH responsiveness in obese patients. After clonidine GH response was abnormal in 14/18 subjects (mean GH peak: 4.1 +/- 1.3 micrograms/l; area under curve: 208.1 +/- 74.2 micrograms/l.h) while all but 5 patients showed an inadequate GH response to GHRH + pyridostigmine (mean GH peak: 13.4 +/- 2.5 micrograms/l; area under curve: 903.4 +/- 171.0 micrograms/l.h). However, in the three patients with low adiposity index, GH response to GHRH + pyridostigmine was significantly higher than that observed in fatter subjects. In addition, GH response to GHRH + pyridostigmine was negatively correlated to age and adiposity index. In conclusion, our data are consistent with the hypothesis of the existence of a complex derangement of GH neuroendocrine regulation in these subjects. Int J Neurosci. 1996 Nov. The aim of this study was to clarify the nature of the sleep abnormalities (excessive daytime sleepiness [EDS] and rapid eye movement [REM] sleep alterations) in Prader-Willi; Syndrome (PWS). Eight PWS patients, 15 normal, 16 narcoleptic, and 16 obese subjects were recorded in the sleep laboratory, both during daytime and nighttime. A principal-finding was that EDS in PWS was associated with an increased amount and depth of sleep. In PWS patients with EDS, compared to those PWS patients without EDS or the narcoleptic, obese, and normal groups, there were significant decreases in wakefulness and increases in percentage of sleep time (ST) and slow-wave sleep (SWS) both during daytime and nighttime testing. Also, in the adult PWS subjects (n = 6), in contrast to normal narcoleptic subjects, intensity of EDS was correlated with increased nocturnal percentage of ST and SWS and % SWS was positively correlated with % ST (both during daytime and nighttime testing). Another principal finding was that in PWS there is a unique alteration of the distribution of REM sleep in relation to controls. PWS patients with EDS or shortened nocturnal REM latencies showed a significantly increased number of REM periods, and a decreased average REM interval between REM periods compared to PWS patients with nonshortened nocturnal REM latencies or to the three control groups. Our data suggest that EDS and REM abnormalities in PWS are not manifestations of a narcoleptic-type syndrome or consequences of obesity. We propose that generalized 24-hour hypoarousal is the primary mechanism underlying the sleep abnormalities in PWS patients. J Child Psychol Psychiatry. 1996 Nov. This study examines the nature, severity and correlates of non-food obsessions and compulsions in 91 people with Prader-Willi syndrome (PWS) aged 5-47 years (mean age = 19 years). Prominent symptoms, seen in 37-58% of the sample, included hoarding; ordering and arranging; concerns with symmetry and exactness; rewriting; and needs to tell, know or ask. A remarkably high proportion of participants had moderate to severe symptom severity ratings; 64% showed symptom-related distress, and 80% showed symptom-related adaptive impairment. The study also compared obsessive-compulsive symptoms in 43 adults with PWS to age- and sex-matched non-retarded adults with obsessive-compulsive disorder (OCD). The PWS and OCD groups showed similar levels of symptom severity and numbers of compulsions; they also showed more areas of symptom similarity than difference. Increased risks of OCD in persons with PWS are strongly indicated. Implications are discussed for pharmacotherapy, behavioral therapy and family support. Minerva Anestesiol. 1996 Oct. The case of a woman of 27 affected by the Prader-Willi syndrome who underwent general anaesthesia for dental surgery is reported. The patient presented severe mental retardation, small stature, moderate muscular hypotonia, hyperphagia, obesity, and diabetes mellitus. Premedication consisted of diazepam and atropine; anaesthesia was induced with propofol and maintained with propofol, fentanyl and N2O; muscle paralysis was obtained with atracurium. A small glottis was observed at laryngoscopy so that a 6 mm cuffed tube was inserted. Surgery lasted 75 minutes; the patient recovered promptly a few minutes following the end of propofol infusion; no postoperative complication was recorded. As hypoglycemia can occur during and after surgery in the Prader-Willi syndrome, plasma samples for glucose, NEFA, insulin, cortisol, and growth hormone (GH) were collected prior to the induction of anaesthesia (A), 20 minutes after starting surgery (B), at the end of surgery (C), and 3 hours later (D). In spite of the infusion of glucose, hyperglycemia was observed just in C and D samples (A:77; B:88; C:245; D:279 mg/dl). Stable NEFA values, within the normal range, were observed (A:77; B:88; C:245; D:279 mg/dl) suggesting poor or absent lipolysis. Insulin decreased progressively during surgery (A:10.5; B:8.8; C:5.4; D:7.0 mU/L). Cortisol peaked in B (A:9.5; B:20.9; C:13.4; D:4.8 micrograms/dl), suggesting normal hypothalamic reactivity to the surgical stimulus. Finally very low GH levels were observed (A:0.04; B:0.07; C:0.06; D:0.09 ng/ml) suggesting GH deficiency, which had possibly affected the size of patient's glottis. Our data support the hypothesis that hypoglycemia in the Prader-Willi syndrome originates from inadequate lipolysis during starvation. Am J Med Genet. 1996 Sep 20. To assess whether sleep abnormalities are related to the genetic abnormalities in Prader-Willi Syndrome (PWS), we performed polysomnographic studies (nighttime and daytime) and determined the chromosome 15 genotypes in eight patients with PWS. Four patients demonstrated sleep onset REM periods (SOREM), and five met the objective polysomnographic criteria for severe or moderate excessive daytime sleepiness (EDS). Three of the four patients with SOREM displayed a paternally derived deletion of chromosome 15q11-q13, whereas the fourth exhibited maternal uniparental heterodisomy in this chromosomal region (UPD). Two of the four patients that did not display SOREM carried paternally derived deletions; the remaining two demonstrated UPD. Four of the five patients with EDS displayed paternal deletions, and the fifth exhibited UPD. One of three patients without evidence of EDS demonstrated paternal deletion; the remaining two showed UPD. Although neither EDS nor SOREM was not consistently associated with a specific genetic abnormality, these phenotypes may be more common in patients with paternal deletions than in those UPD. Sleep abnormalities in PWS cannot be explained by a single genetic model. Eur Respir J. 1996 Jul. The clinical course and changes in hypercapnic ventilatory drive over time were serially assessed before and after tracheostomy placement in a 14 year old, morbidly obese female patient with Prader-Willi syndrome, severe obstructive sleep apnoea, and obesity-hypoventilation syndrome. A tracheostomy became necessary after supplemental oxygen and continuous positive airway pressure (CPAP) had failed to improve the severity of nocturnal hypoventilation. Continued improvement in the slope to rebreathing hyperoxic hypercapnia occurred from 2-10 weeks after tracheotomy in conjunction with night-time bilevel pressure ventilation, and remained unchanged thereafter. In contrast, increases in mean resting minute ventilation at an end-tidal carbon dioxide tension (PET,CO2) of 8 kPa (60 mmHg) were documented even after 30 weeks. This case study illustrates the time-frame of dynamic ventilatory changes occurring after removal of upper airway resistance and normalization of nocturnal alveolar ventilation. From the full text article: In adult patients with severe obstructive sleep apnoea syndrome (OSAS), a beneficial effect is observed 3 months after the reversal of upper airway resistance by tracheostomy placement. Both improved resting breathing pattern and hypercapnic ventilatory responses (HCVR) were reported in seven patients who were hypercapnic during wakefulness [1–3]. However, such beneficial effect has not yet been demonstrated in children with severe OSAS in whom tracheotomy may be required. Prader-Willi syndrome (PWS) is the most common genetic disorder leading to obesity [4]. Hypogonadism, short stature with small hands and feet, behavioural disorders, as well as compulsive eating are characteristic of this syndrome [4]. However, with strict dietary intake restrictions, obesity may be prevented in PWS patients. Whilst absent or markedly reduced ventilatory response both to transient and isocapnic hypoxia during wakefulness [5, 6] are universally found both in obese and nonobese PWS patients, HCVR is blunted only in obese PWS patients [5, 7]. Furthermore, abnormal sleep patterns, including daytime somnolence, hypoventilation, oxygen desaturations during rapid eye movement (REM) sleep and abnormal sleep architecture, tend to occur more frequently in obese PWS [8], suggesting that additional obesity-related respiratory loads may contribute to modification of hypercapnic responsivity over time. We report the case of a 14 year old obese female PWS patient with severe OSAS and obesity-hypoventilation syndrome, in whom resting ventilatory measures and HCVR were assessed prior to and serially after tracheotomy and nocturnal ventilatory support. Case report A 14 year old female previously diagnosed with PWS was urgently admitted following the insidious onset of fever, and diminished mental and physical activity levels over a 3 day period. Her past medical history was positive for recurrent urinary tract infections, uncontrollable appetite and feeding schedules, as well as obsessive compulsive behaviours, such as skin-pinching and hair-pulling. In addition, marked weight gain, loud snoring and daytime somnolence had been observed to develop since institution of trimonthly hormonal therapy with medroxyprogesterone for aggressive verbal behaviour. The patient's weight was 77 kg, height 143 cm, and calculated body mass index (BMI) 37.6 kg·m-2. Physical examination disclosed a markedly obese patient, in no apparent distress, with a rectal temperature of 38.3 °C, a respiratory frequency (fR) of 14 breaths·min-1, pulse rate 114 breaths·min-1, and blood pressure of 117/77 mmHg. The patient was somnolent, although easily arousable on verbal command. No lymphadenopathy, icterus, cyanosis or clubbing were found. The head and neck were normal. Decreased breath sounds and diffuse rales were present over both lungs. The remainder of the examination revealed only physical stigmata characteristic of Prader-Willi syndrome, such as small hands and feet, sparse pubic, axillary and body hair, and small clitoris and labia minora. Arterial blood gas values obtained whilst awake and breathing room air revealed a pH of 7.38, an arterial oxygen tension (Pa,O2) of 8.7 kPa (65 mmHg), and an arterial carbon dioxide tension (Pa,CO2) of 6.9 kPa (52 mmHg). A radiograph of the chest disclosed bilateral interstitial infiltrates, and therapy was instituted with intravenous antibiotics (cefuroxime and erythromycin), and supplemental oxygen at 2 L·min-1 delivered via nasal cannula. However, during sleep, loud snoring, and marked oxygen desaturations to the low 60s % were noted, and arterial blood gas measurements at this time revealed a pH of 7.25, a Pa,O2 of 5.1 kPa (38 mmHg), and a (Pa,CO2) of 10.4 kPa (78 mmHg). The patient was intubated and mechanically ventilated for several days, with rapid clearing of chest infiltrates and auscultatory findings, as well as normalization of arterial blood gas values. However, although minimal ventilatory support requirements (continuous positive airway pressure (CPAP) 6 cmH2O; inspiratory oxygen fraction (FI,O2, 24%) were necessary during wakefulness, increasing support was necessary during sleep due to worsening hypercapnia and hypoxaemia (assist/control mode; fR 14 breaths·min-1; positive endexpiratory pressure (PIP) 40 cmH2O; positive end-expiratory pressure (PEEP) 6 cmH2O; FI,O2 28%). The patient was finally extubated on Day 5 after 12 h of CPAP, and 2 days later, an overnight polysomnogram was performed which confirmed the presence of severe OSAS (table 1). On Day 9 of hospitalization, the patient developed cyanosis and bradycardia (45 beats·min-1) during sleep. Arterial blood gas measurements on supplemental oxygen by mask revealed a pH of 7.07 and Pa,CO2 of 12.1 kPa (91 mmHg), and the patient was intubated and mechanically ventilated. In the following 12 days, despite minimal ventilatory settings, several attempts to extubate the patient were unsuccessful due to development of severe alveolar hypoventilation (Pa,CO2 9.3 kPa (>70 mmHg)) during sleep. On day 20, rebreathing ventilatory responses to hypercapnia were first assessed (see below), and 2 days later, a tracheostomy was performed. The patient was gradually weaned from daytime ventilation over the next 14 days. Arterial blood gases and oxygen saturation measured during wakefulness were within normal limits. To maintain adequate oxygenation and Pa,CO2 6 kPa (<45 mmHg) ventilatory support was provided during night-time sleep with bilevel positive airway pressure (BiPAP), ventilation (Respironics, Murrysville, PA, USA) at the following settings: assist/control mode; PIP 20 cmH2O; PEEP 6 cmH2O; and fR 10 breaths·min-1. On Day 47, the patient was discharged on nighttime bilevel ventilation at the above settings, and underwent two additional sleep studies at 4 and 9 weeks after tracheostomy placement (table 1). ... Results The results of hypercapnic ventilatory tests are shown in figures 1 and 2. Improvements in the slope of HCVR occurred within 2 weeks of tracheotomy and nocturnal bilevel pressure ventilatory support and plateaued at 10 weeks after surgery (fig. 1). Ongoing increases in resting V'E as well as in V'E measured at PET,CO2 of 8 kPa (60 mmHg) were still noticed 30 weeks after surgery (fig. 2). Discussion The present case documents the time course for recovery of hypercapnic ventilatory drive after removal of upper airway obstruction and night-time ventilatory support. Although no weight reduction occurred in our patient over time, marked increases in spontaneous ventilation during wakefulness, at PET, CO2 of 8 kPa (60 torr), as well as in the HCVR slope occurred during the initial 10 weeks following tracheotomy, and the latter remaining unchanged thereafter (figs. 1 and 2). Thus, analogous to studies in adults [12], reduction of upper airway resistance, normalization of alveolar gas exchange during sleep, and prevention of sleep fragmentation due to apnoea resulted in gradual improvement of waking ventilatory measures, finally allowing for discontinuation of daytime ventilatory support 2 weeks after tracheotomy. However, although improved, persistent hypoventilation during sleep was still present after 9 weeks of treatment. GUILLEMINAULT and CUMMISKEY [1] reported significant increases in the slope of HCVR after 12–16 weeks in five tracheotomized adult patients with OSAS, and comparable findings in three additional patients were documented within similar postoperative periods [2, 3]. The time course of such improved hypercapnic drive was not serially assessed. More recently, increased ventilatory measures at a PET,CO2 of 8 kPa (60 mmHg) were found in daytime hypercapnic OSAS patients as early as 48 h following institution of CPAP therapy, and continued to improve with continuing CPAP treatment for 2 weeks [13]. However, the slope of the HCVR remained unchanged over time [13]. Improvements in daytime ventilatory measures and chemosensitivity evolved slowly in our patient, despite normalization of alveolar ventilation during sleep with bilevel pressure ventilatory support. The absence of further improvement in this patient could indicate that she may have reached her "normal" HCVR, or that no further improvements would occur unless other therapeutic measures, such as weight loss or respiratory stimulants, were instituted. Evaluation of control of breathing in awake, adult OSAS patients suggests that in patients with normocapnia during wakefulness, normal hypercapnic ventilatory and mouth occlusion pressures are found [14]. In contrast, in hypercapnic patients, the ventilatory CO2 response is usually depressed [15]. In nonobese children with OSAS, ventilatory responses to hypercapnia and hypoxia are similar to those found in healthy controls [16], suggesting that abnormal central respiratory drive is not a frequent component in the pathophysiology of OSAS in childhood. The additional contribution of obesity to respiratory drive in our patient is unclear. Obesity leads to decreased chest wall compliance due to deposition of adipose tissue, and such elastic load may elicit early enhancement of neuromuscular respiratory output [17]. However, with prolonged mass loading, hypoventilation may develop over time [18]. In a recent study, we found that obese PWS patients had significantly diminished hypercapnic ventilatory slopes, whilst nonobese PWS patients demonstrated comparable slopes to those found in age-, gender and BMI-matched controls [5]. Thus, the absence of continued HCVR improvement after 10 weeks following tracheotomy in our patient may represent the net effect of daytime mass loading due to obesity, which may impinge on the complete recovery of HCVR to normal values [19], or an unrelated, diminished inborn hypercapnic ventilatory drive. Also worthy of mention was the relative bradypnoea recorded on admission in the presence of fever. We are uncertain of the exact significance of this sign, which could underlie either the absence of peripheral chemoreceptor response [6], or indicate disturbances in feedforward mechanisms originating in hypothalamic structures [5, 6]. In summary, the temporal improvements in waking ventilation and hypercapnic drive occurring after tracheotomy and bilevel pressure ventilation are reported in a Prader-Willi Syndrome patient over a period of 30 weeks. This interesting case emphasizes the contribution of sleep-disordered breathing to blunted ventilatory responses to carbon dioxide and respiratory failure, and the potential for partial reversibility of such changes by therapeutic measures leading to adequate gas exchange. Rinsho Shinkeigaku. 1996 Jun. We report a case of Prader-Willi syndrome (PWS) complicated with juvenile stroke. The patient is a 19-year-old man with right hemiplegia, who has had a history of non-insulin-dependent diabetes mellitus (NIDDM) for ten years. The diagnosis of PWS was confirmed genetically by the method of fluorescence in situ hybridization which showed the deletion of chromosome 15. His brain MRI revealed abnormal signal intensities in the left basal ganglia and around the right trigone of the lateral ventricle. Angiographic examination showed occlusions of bilateral proximal middle cerebral arteries with basal moyamoya vessels. The left vertebral artery was also occluded at its origin. Only a few cases of PWS complicated with stroke have been reported before and, to date, there has been no case with arterial occlusion similar to our case. Though the cause of these arterial occlusions is unknown, it may be related to arteriosclerosis following NIDDM. Am J Respir Crit Care Med. 1996 Jan. Ventilatory responses to peripheral chemoreceptor stimuli are absent in patients with Prader-Willi syndrome (PWS) during wakefulness. Because arousal from sleep after rapidly developing hypoxia may require intact peripheral chemoreceptor function, we hypothesized that blunted hypoxic arousal responses during sleep Stage 3/4 would be present in PWS. Thirteen patients with PWS (mean age, 23.4 +/- 3.7 +/- SEM yr; 46% male; body mass index [BMI], 28.9 +/- 1.6 kg/m2) and 11 matched control subjects (mean age 28.0 +/- 5.4 yr; 54% male; BMI, 28.8 +/- 3.1 kg/m2) were studied. An abrupt decrease in inspired O2 tension to 80 mm Hg was introduced until arousal occurred or for a maximum of 3 min. One of the 13 patients with PWS and seven of the 11 control subjects were aroused by the hypoxic challenge (p < 0.02). During hypoxia, heart rate increased by 9 +/- 2% in the PWS group versus 22 +/- 4% in the control group (p < 0.005). Respiratory rate did not change in the PWS group (4 +/- 2%; p = NS), but it increased by 13 +/- 2% in the control group (p < 0.02). We conclude that abnormal arousal and cardiorespiratory responses to hypoxia are frequent in PWS. We postulate that intact peripheral chemoreceptor function is an important component underlying arousal mechanisms to rapidly developing hypoxia during sleep. Sleep. 1996 Jan. A 9 1/2-year-old Taiwanese boy with Prader-Willi syndrome had the following characteristics: difficulties with sucking, feeding and hypotonia during infancy, a dysmorphic face (triangular mouth, high arched palate, almond-shaped eyes and large head circumference with a relatively narrow bifrontal diameter), borderline intelligence, hypogonadism, hyperphagia, skin picking and truncal obesity. The boy experienced two hypersomnia episodes, at age 8 and 9 years, with both episodes lasting for 10 days. During the two episodes, he was found to have an exacerbated case of hyperphagia, pica, poor emotional control, stereotyped speech and agitated behavior upon awakening. After each episode, the boy had complete remission. Our findings show that the two episodes are compatible with Kleine-Levin syndrome. The relationship between the two syndromes, the Prader-Willi syndrome and the Kleine-Levin syndrome, deserves further study. Pediatr Radiol. 1996. Prader-Willi syndrome (PWS) is an unusual genetic disorder characterized by short stature, obesity, hypogonadism, hypotonia, cognitive impairment, and dysmorphic facies. There is an interstitial deletion of the proximal long arm of chromosome 15 in about 70 % of patients. Some of these clinical features suggest a central hypothalamic/pituitary dysfunction, and recent investigations have demonstrated a marked impairment in spontaneous growth hormone (GH) secretion. We studied 15 GH-deficient PWS patients by magnetic resonance imaging (MRI) to determine whether there was a diminution in the gross morphological size of the anterior pituitary gland, the site of GH synthesis. We also set out to catalog the pertinent imaging findings in this patient population. Our results indicate that this is the first report documenting pituitary size by MRI in PWS patients. No statistically significant difference was found in the height of the anterior pituitary gland in PWS patients compared with either normal children or children with isolated GH deficiency. An interesting imaging finding is that three of 15 patients (20 %) demonstrated complete absence of the posterior pituitary bright spot (PPBS), and a fourth patient demonstrated a small PPBS. These observations reflect an objective physiologic disturbance in the hypothalamus. The clinical and radiologic implications of these findings are discussed. [ 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996 | 1995 | 1994 | 1993 | 1992 | 1991 | 1990 | 1980-1989 | 1979 and prior ] |