Thyroid function in patients with Prader-Willi syndrome: an Italian multicenter study of 339 patients.

Background Prader-Willi syndrome (PWS) is a genetic disorder due to loss of expression of paternally transcribed genes of the imprinted region of chromosome 15q11-13. PWS is characterized by peculiar signs and symptoms and many endocrine abnormalities have been described (growth hormone deficiency, hypogonadotropic hypogonadism). The abnormalities of thyroid function are discussed in literature and published data are discordant. The aim of our study was to report the thyroid function in patients with PWS to identify the prevalence of thyroid dysfunction. Methods Thyroid function tests were carried out in 339 patients with PWS, aged from 0.2 to 50 years. A database was created to collect personal data, anthropometric data, thyroid function data and possible replacement therapy with L-thyroxine. Subjects were classified according to thyroid function as: euthyroidism (EuT), congenital hypothyroidism (C-HT), hypothyroidism (HT - high thyroid-stimulating hormone [TSH] and low free thyroxine [fT4]), central hypothyroidism (CE-H - low/normal TSH and low fT4), subclinical hypothyroidism (SH - high TSH and normal fT4), and hyperthyroidism (HyperT - low TSH and high fT4). Results Two hundred and forty-three out of 339 PWS patients were younger than 18 years (71.7%). The prevalence of thyroid dysfunction was 13.6%. Specifically, C-HT was found in four children (1.18%), HT in six patients (1.77%), CE-H in 23 patients (6.78%), SH in 13 patients (3.83%), and HyperT in none. All other subjects were in EuT (86.4%). Conclusions Hypothyroidism is a frequent feature in subjects with PWS. Thyroid function should be regularly investigated in all PWS patients both at the diagnosis and annually during follow-up.

Growth hormone therapy and respiratory disorders: long-term follow-up in PWS children.

CONTEXT: Adenotonsillar tissue hypertrophy and obstructive sleep apnea have been reported during short-term GH treatment in children with Prader-Willi syndrome (PWS). OBJECTIVE: We conducted an observational study to evaluate the effects of long-term GH therapy on sleep-disordered breathing and adenotonsillar hypertrophy in children with PWS. DESIGN: This was a longitudinal observational study. PATIENTS AND METHODS: We evaluated 75 children with genetically confirmed PWS, of whom 50 fulfilled the criteria and were admitted to our study. The patients were evaluated before treatment (t0), after 6 weeks (t1), after 6 months (t2), after 12 months (t3), and yearly (t4-t6) thereafter, for up to 4 years of GH therapy. The central apnea index, obstructive apnea hypopnea index (OAHI), respiratory disturbance index, and minimal blood oxygen saturation were evaluated overnight using polysomnography. We evaluated the adenotonsillar size using a flexible fiberoptic endoscope. RESULTS: The percentage of patients with an OAHI of >1 increased from 3 to 22, 36, and 38 at t1, t4, and t6, respectively (χ(2) = 12.2; P < .05). We observed a decrease in the respiratory disturbance index from 1.4 (t0) to 0.8 (t3) (P < .05) and the central apnea index from 1.2 (t0) to 0.1 (t4) (P < .0001). We had to temporarily suspend treatment for 3 patients at t1, t4, and t5 because of severe obstructive sleep apnea. The percentage of patients with severe adenotonsillar hypertrophy was significantly higher at t4 and t5 than at t0. The OAHI directly correlated with the adenoid size (adjusted for age) (P < .01) but not with the tonsil size and IGF-1 levels. CONCLUSION: Long-term GH treatment in patients with PWS is safe; however, we recommend annual polysomnography and adenotonsillar evaluation.

Central adrenal insufficiency in young adults with Prader-Willi syndrome.

OBJECTIVE: A high prevalence (60%) of central adrenal insufficiency (CAI) has been reported in Prader-Willi syndrome (PWS) using the metyrapone test. We have assessed CAI in adults with PWS using the low-dose short synacthen test (LDSST). DESIGN: Basal cortisol and ACTH, and 30-min cortisol after the administration of 1 µg synacthen, were determined in 53 PWS adults (33 females). A peak cortisol value of ≥500 nmol/l was taken as normal. Hormonal profiles were analysed in relation to gender, genotype and phenotype. Deficient patients were retested by high-dose short synachten test (HDSST) or a repeat LDSST. RESULTS: Mean ± SD basal cortisol and ACTH were 336·6 ± 140·7 nmol/l and 4·4 ± 3·7 pmol/l respectively. Cortisol rose to 615·4 ± 135·0 nmol/l after LDSST. Eight (15·1%) patients had a peak cortisol response <500 nmol/l, with a lower mean ± SD (range) basal cortisol of 184·9 ± 32·0 (138·0-231·7) compared with 364·1 ± 136·6 (149·0-744·5) in normal responders (P < 0·001). Seven of the eight patients underwent retesting, with 4 (7·5%) showing persistent suboptimal responses. Basal and peak cortisol correlated in females (r = 0·781, P < 0·001). Logistic regression revealed that only female gender and baseline cortisol were predictors of cortisol peaks (adjusted R square 0·505). CONCLUSIONS: Although CAI can be part of the adult PWS phenotype, it has a lower prevalence (7·5%) than previously reported. Clinicians are advised to test PWS patient for CAI. Our study also shows that basal cortisol is closely correlated with adrenal response to stimulation, indicating that its measurement may be helpful in selecting patients for LDSST.

Early manifestations in a cohort of children prenatally diagnosed with 47,XYY. Role of multidisciplinary counseling for parental guidance and prevention of aggressive behavior.

BACKGROUND: An increasing number of foetuses are recognized as having double Y because of the widespread use of prenatal screening using chorionic villus sampling and amniocentesis. 47, XYY karyotype occurs in about one out of 1,000 newborn males, but it is not often detected unless it is diagnosed during prenatal testing. Despite the fact that unbiased follow-up studies demonstrate largely normal post-natal development of young men with 47, XYY, there is a scarcity of controlled studies about the neurological, cognitive and behavioural phenotype which remains the main reason for anxiety and anticipatory negative attitudes of parents. Furthermore, prejudices still exist among professionals and the general population concerning the relationship between this sex chromosome aneuploidy and aggressive and antisocial behaviours. METHODS: We report on the clinical follow-up of children diagnosed prenatally with a 47,XYY karyotype, whose parents received multidisciplinary counselling and support at time of diagnosis. The specific focus of our study is on auxology, facial features, developmental milestones, behaviour, detection of aggressiveness as well as the evaluation of parental attitudes toward prenatal counselling. Clinical evaluations including auxological measurements and dysmorphological descriptions were as conducted on 13 boys aged 9 month -7 years. The Child Behavior Check List test specific for age and a 15 item questionnaire were administered to both parents. An update of ongoing problems was carried out by means of a telephone interview two years later. RESULTS: Our results show that, from birth, weight, height and head circumference were above average values while some facial features such mild hypertelorism are overrepresented when compared to parents' facial features. Language delay was detected in 8 out of 11 children older than 20 months. Parental attitudes were found to be favourable toward prenatal diagnoses of sexual chromosome aneuploidies. CONCLUSIONS: Our data, although limited, is similar to other observational studies, and serves to alert clinicians about opportunities to delineate new and appropriate educational interventions that target the specific learning challenges of XYY boys. Our experience better defines the early manifestation of XYY and should aid those involved in prenatal counselling and paediatric surveillance.

Assessment of central adrenal insufficiency in children and adolescents with Prader-Willi syndrome.

OBJECTIVE: A recent study evidenced by metyrapone test a central adrenal insufficiency (CAI) in 60% of Prader-Willi syndrome (PWS) children. These results were not confirmed in investigations with low [Low-Dose Tetracosactrin Stimulation Test (LDTST), 1 µg] or standard-dose tetracosactrin stimulation tests. We extended the research by LDTST in paediatric patients with PWS. DESIGN: Cross-sectional evaluation of adrenal stress response to LDTST in a PWS cohort of a tertiary care referral centre. PATIENTS: Eighty-four children with PWS. MEASUREMENTS: Assessment of adrenal response by morning cortisol and ACTH dosage, and 1-µg tetracosactrin test. Response was considered appropriate when cortisol reached 500 nm; below this threshold, patients were submitted to a second test. Responses were correlated with the patients' clinical and molecular characteristics to assess genotype-phenotype correlation. RESULTS: Pathological cortisol peak responses to the LDTST were registered in 12 patients (14.3%) who had reduced basal (169.4 ± 83.3 nm) and stimulated (428.1 ± 69.6 nm) cortisol levels compared to patients with normal responses (367.1 ± 170.6 and 775.9 ± 191.3 nm, P < 0.001). Body mass index standard deviation score was negatively correlated with basal and peak cortisol levels (both P < 0.001), and the patients' ages (P < 0.001). In patients with deletion on chromosome 15, the cortisol peak was significantly lower than that in uniparental disomy (UPD) cases (P = 0.030). At multiple regression analysis, the predictors of peak response were basal cortisol, age, and UPD subclass (r(2) = 0.353, P < 0.001). Standard-dose (250 µg) tetracosactrin test confirmed CAI in 4/12 patients (4.8% of the cohort). CONCLUSIONS: Our results support the hypothesis that, albeit rare, CAI may be part of the PWS in childhood.

Growth hormone secretory pattern in non-obese children and adolescents with Prader-Willi syndrome.

The aetiology of impaired growth hormone (GH) secretion in Prader-Willi syndrome (PWS) remains controversial due to the common occurrence of obesity. To further clarify whether suboptimal GH secretion in PWS is an artefact of excess weight, we evaluated both GH immunological activity and GH bioactivity after arginine administration in 23 non-obese PWS patients [seven females, aged 6.9 +/- 0.9 years, body mass index (BMI) SDS 0.63 +/- 0.26], in comparison with a control group of 32 healthy subjects, matched for age, gender and BMI (10 females, aged 7.9 +/- 0.3 years, BMI SDS 0.21 +/- 0.20). Serum GH concentration was measured with a time-resolved immunofluorometric assay (IFMA), while GH bioactivity was evaluated by the Nb2 cell bioassay. Serum IGF-I concentrations were measured by double-antibody RIA. GH mean peak after pharmacological stimulation was significantly lower in PWS individuals compared with controls when measured either by IFMA (6.05 +/- 1.23 microg/L vs. 23.7 +/- 1.06 microg/L, p < 0.0001) or by Nb2 (6.87 +/- 0.55 microg/L vs. 12.88 +/- 0.19 microg/L, p < 0.0001). Analysis of integrated GH secretion (AUC) confirmed that the PWS group differed significantly from the control subjects (387.9 +/- 76.1 microg/L/h vs. 1498.1 +/- 56.2 microg/L/h, p < 0.0001); the same result was obtained when the GH rise after arginine administration was expressed as nAUC (278.2 +/- 53.3 microg/L/h vs. 1443.6 +/- 52.5 microg/L/h, p < 0.0001). PWS patients had an IGF-I SDS significantly lower than those found in control subjects (p < 0.0001). Subnormal IGF-I values were present in 19 PWS individuals (82.6%) and two healthy controls (6.2%). These findings are in agreement with the hypothesis that a complex derangement of hypothalamus-pituitary axis occurs in PWS.

Triple X syndrome: characteristics of 42 Italian girls and parental emotional response to prenatal diagnosis.

We report clinical and behavioural evaluation data in 42 Italian girls with triple X syndrome whose diagnosis was made prenatally between 1998 and 2006 in three Italian centres. At initial evaluation, reproductive and medical histories were collected. Clinical assessment of the child was performed by a clinical geneticist and included a detailed personal history, physical evaluation and auxological measurements. To analyse how parents coped with specific events in the prenatal and postnatal periods, we conducted an interview that included 35 specific questions designed to elicit retrospective judgements on prenatal communication, present and future worries, needs and expectations. In a subset of probands, we also administered the formal Italian Temperament Questionnaire assessment test that investigates adaptation, general environment and socialisation. This test also assesses the emotional component of temperament. Clinical results in the affected children are similar to those previously reported with evidence of increased growth in the pre-puberal age and an average incidence of congenital malformation and health needs. Median age for the time first words were pronounced was 12 months, showing a slight delay in language skills, which tended to improve by the time they reached school age. Parental responses to the interview demonstrated residual anxiety but with a satisfactory adaptation to and a positive recall of the prenatal counselling session. Parental adaptation of the 47,XXX girls require indeed a proper educational support. This support seems to be available in Italy. An integrated approach to prenatal counselling is the best way to manage the anxiety and falsely imagined consequences that parents feel after being told that their foetus bears such a genetic abnormality.

The Italian National Survey for Prader-Willi syndrome: an epidemiologic study.

Twenty-five medical centers and the Prader-Willi Syndrome (PWS) Association collaborated on a study which attempted to identify all people with genetically confirmed diagnosis of PWS living in Italy. Investigators of the participating centers contacted PWS subjects and/or their family, filled in a specially developed form with the required data and forwarded this information by email. The study identified 425 subjects (209 males and 216 females, between the ages of 0.4-46.7). Two hundred thirty-eight patients had del15, 104 had UPD15, 4 demonstrated a translocation affecting chromosome 15 and 79 showed a positive methylation test. There were fewer subjects found over the age of 35, probably due to the low rate of identification of older PWS patients as well as the high mortality rate. There were a greater number of male children and adolescents with PWS whilst, amongst adults, there were more females. As expected, the majority of subjects with PWS were obese, especially in adult life. Nevertheless, it is noteworthy that 26% of patients aged between 6 and 17 were normal weight. A total of 212 subjects had received GH treatment, of which 141 were still receiving therapy, while the remaining 71 had stopped. In children and adolescents (233 cases), 89 subjects had never undergone GH therapy. Eighteen PWS patients had died in the past 20 years. Obesity-related cardiovascular and respiratory diseases were the cause of death, both during childhood and after 18 years of age. Three children died suddenly whilst undergoing GH therapy. Respiratory infection and cardiac illness were the causes of death in two cases. There was no definitive cause of death found in the third case. Overall, there was no increase in number of deaths during GH treatment, suggesting that GH administration in patients with PWS, as a group, does not increase the risk of death.

Cut-off limits of the GH response to GHRH plus arginine test and IGF-I levels for the diagnosis of GH deficiency in late adolescents and young adults.

OBJECTIVE: To define the appropriate diagnostic cut-off limits for the GH response to GHRH+arginine (ARG) test and IGF-I levels, using receiver operating characteristics (ROC) curve analysis, in late adolescents and young adults. DESIGN AND METHODS: We studied 152 patients with childhood-onset organic hypothalamic-pituitary disease (85 males, age (mean+/-s.e.m.): 19.2+/-0.2 years) and 201 normal adolescents as controls (96 males, age: 20.7+/-0.2 years). Patients were divided into three subgroups on the basis of the number of the other pituitary hormone deficits, excluding GH deficiency (GHD): subgroup A consisted of 35 panhypopituitary patients (17 males, age: 21.2+/-0.4 years), subgroup B consisted of 18 patients with only one or with no more than two pituitary hormone deficits (7 males, age: 20.2+/-0.9 years); and subgroup C consisted of 99 patients without any known hormonal pituitary deficits (60 males, age: 18.2+/-0.2 years). Both patients and controls were lean (body mass index, BMI<25 kg/m(2)). Patients in subgroup A were assumed to be GHD, whereas in patients belonging to subgroups B and C the presence of GHD had to be verified. RESULTS: For the GHRH+ARG test, the best pair of highest sensitivity (Se; 100%) and specificity (Sp; 97%) was found choosing a peak GH of 19.0 microg/l. For IGF-I levels, the best pair of highest Se (96.6%) and Sp (74.6%) was found using a cut-off point of 160 microg/l (SDS: -1.3). Assuming 19.0 microg/l to be the cut-off point established for GHRH+ARG test, 72.2% of patients in subgroup B and 39.4% in subgroup C were defined as GHD. In patients belonging to group B and C and with a peak GH response <19 microg/l to the test, IGF-I levels were lower than 160 microg/l (or less than 1.3 SDS) in 68.7 and 41.6% of patients respectively predicting severe GHD in 85.7% of panhypopituitary patients (subgroup A). CONCLUSIONS: In late adolescent and early adulthood patients, a GH cut-off limit using the GHRH+ARG test lower than 19.0 microg/l is able to discriminate patients with a suspicion of GHD and does not vary from infancy to early adulthood.

Quality of life assessment in a sample of patients affected by Prader-Willi syndrome.

AIM: The goals of this study are to investigate the quality of life of Prader-Willi syndrome patients and to evaluate the relationship between quality of life and the clinical picture. METHODS: We performed a multicentric study on 40 consecutive patients with Prader-Willi syndrome. Quality of life was evaluated through the Short Form-36 and the Child Health Questionnaire-Parent Form-50 according to the age of patients. RESULTS: In patients older than 14 years old, quality of life is intensely impaired both in mental and physical aspects. Weight at the moment of the observation, birthweight and facial features are the main variables that influence quality of life. In patients who are 14 years old or younger, the Family Activity and Physical scores are lower for those patients with characteristic facial features and in patients with decreased fetal movement or infantile lethargy. Self-esteem is lower in patients with a higher Mini Mental Score. CONCLUSIONS: Physical and mental aspects of quality of life are impaired in Prader-Willi patients, weight is the clinical finding which mainly influences negatively the physical aspects of quality of life. However, weight does not cause mental problems. These are mainly due to the presence of characteristic facial features. Interestingly, a high birthweight is associated with less impairment of the mental aspects of quality of life.

Diagnosis of GH deficiency in the transition period: accuracy of insulin tolerance test and insulin-like growth factor-I measurement.

OBJECTIVE: A consensus exists that severe growth hormone deficiency (GHD) in adults is defined by a peak GH response to insulin-induced hypoglycemia (insulin tolerance test, ITT) of less than 3 microg/l based on a cohort of subjects with a mean age of 45 years. DESIGN AND METHODS: By considering one of the following two criteria for the diagnosis of probable permanent GHD, i.e. the severity of GHD (suggested by the presence of multiple pituitary hormone deficiencies (MPHD)) or the magnetic resonance (MR) imaging identification of structural hypothalamic-pituitary abnormalities, 26 patients (17 males, 9 females, mean age 20.8 +/- 2.3 years, range 17-25 years) were selected for re-evaluation of the GH response to ITT and their IGF-I concentration. Eight subjects had isolated GHD (IGHD) and 18 had MPHD. Normative data for peak GH were obtained after ITT in 39 healthy subjects (mean age 21.2 +/- 4.4 years, range 15.1-30.0 years) and the reference range for IGF-I was calculated using normative data from 117 healthy individuals. RESULTS: Mean peak GH response to ITT was significantly lower in the 26 patients (1.8+/-2.0 microg/l, range 0.1-6.1 microg/l) compared with the 39 controls (18.5 +/- 15.5 microg/l, range 6.1-84.0 microg/l; P < 0.0001). One subject with septo-optic dysplasia had a peak GH response of 6.1 microg/l that overlapped the lowest peak GH response obtained in normal subjects. There was an overlap for IGF-I SDS between subjects with IGHD and MPHD, as well as with normal controls. The diagnostic accuracy of a peak GH response of 6.1 microg/l showed a 96% sensitivity with 100% specificity. The maximum diagnostic accuracy with IGF-I SDS was obtained with a cut-off of -1.7 SDS (sensitivity 77%, specificity 100%) while an IGF-I < or = - 2.0 SDS showed a sensitivity of 62%. CONCLUSION: Our data show that the cut-off value of the peak GH response to ITT of less than 3 microg/l or 5 microg/l and of IGF-I of less than -2.0 SDS are too restrictive for the diagnosis of permanent GH deficiency in the transition period. We suggest that permanent GHD could be investigated more accurately by means of an integrated analysis of clinical history, the presence of MPHD, IGF-I concentration and the MR imaging findings of structural hypothalamic-pituitary abnormalities.