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.

Four novel mutations of the LHX3 gene cause combined pituitary hormone deficiencies with or without limited neck rotation.

CONTEXT: The Lhx3 LIM-homeodomain transcription factor gene is required for development of the pituitary and motoneurons in mice. Human LHX3 gene mutations have been reported in five subjects with a phenotype consisting of GH, prolactin, TSH, LH, and FSH deficiency; abnormal pituitary morphology; and limited neck rotation. OBJECTIVE: The objective of the study was to determine the frequency and nature of LHX3 mutations in patients with isolated GH deficiency or combined pituitary hormone deficiency (CPHD) and characterize the molecular consequences of mutations. DESIGN: The LHX3 sequence was determined. The biochemical properties of aberrant LHX3 proteins resulting from observed mutations were characterized using reporter gene and DNA binding experiments. PATIENTS: The study included 366 patients with isolated GH deficiency or CPHD. RESULTS: In seven patients with CPHD from four consanguineous pedigrees, four novel, recessive mutations were identified: a deletion of the entire gene (del/del), mutations causing truncated proteins (E173ter, W224ter), and a mutation causing a substitution in the homeodomain (A210V). The mutations were associated with diminished DNA binding and pituitary gene activation, consistent with observed hormone deficiencies. Whereas subjects with del/del, E173ter, and A210V mutations had limited neck rotation, patients with the W224ter mutation did not. CONCLUSIONS: LHX3 mutations are a rare cause of CPHD involving deficiencies for GH, prolactin, TSH, and LH/FSH in all patients. Whereas most patients have a severe hormone deficiency manifesting after birth, milder forms can be observed, and limited neck rotation is not a universal feature of patients with LHX3 mutations. This study extends the known molecular defects and range of phenotypes found in LHX3-associated diseases.

Bisphosphonate treatment of bone fibrous dysplasia in McCune-Albright syndrome.

One of the main features of McCune-Albright syndrome is bone fibrous dysplasia (BFD) often associated with severe clinical outcomes, such as bone pain, bone deformities and pathological fractures. Medical treatment with bisphosphonates started 15 years ago. Recent trials in pediatric patients with BFD have shown encouraging results. We evaluated long-term efficacy and safety of pamidronate treatment of BFD in children and adolescents with MAS. The drug was administered at 4 month-1 year intervals according to alkaline phosphatase levels. The study included 14 patients (10 females and 4 males between the ages of 5.3 and 18.7 years) with moderate or severe BFD. Follow up lasted 1.9-9 years. Bone pain, fractures, deformities, and bone turnover markers were evaluated before every therapeutic course. The study shows the beneficial effects of long-term bisphosponate treatment on BFD lesions leading to reduced fracture rate and bone pain, and radiological evidence of long bone lesion healing.

A variation in a Pit-1 site in the growth hormone gene (GH1) promoter induces a differential transcriptional activity.

The proximal promoter of the human growth hormone gene (GH1) is highly polymorphic. We tested if promoter haplotypes differing at possibly functional sites, namely -278T/G (in the NF1 binding site), -75A/G (in the proximal Pit-1 binding site) and -57G/T (in the VDR binding site), induced a different luciferase activity when transfected in a rat pituitary cell line. The presence of a G instead of an A at position -75 induced a more than two-fold reduced activity (p<0.0001). In accordance with this findings the electrophoretic mobility shift assay demonstrated a reduced affinity of the -75G for the pituitary transcription factor Pit-1. Despite the strong effect of this polymorphism in vitro, the -75G variation was not associated to an impairment of the GH secretion in vivo.

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.

Ghrelin secretion in childhood is refractory to the inhibitory effect of feeding.

Ghrelin, a natural GH secretagogue, is predominantly produced by the stomach. Ghrelin has other actions including orexant activity, modulation of energy balance, and modulation of endocrine and nonendocrine functions. Ghrelin secretion is increased by fasting and energy restriction but decreased by food intake, glucose, insulin, and somatostatin. Ghrelin secretion does not seem to be a function of age; in fact, morning ghrelin levels after overnight fasting in prepubertal and pubertal children are similar to those in young adults. To clarify whether children and adults have the same sensitivity to the inhibitory effect of food intake, we studied the ghrelin response to a standardized light breakfast (SLB) in 10 prepubertal lean children whose results were compared with those recorded in 19 normal-weight adults. Basal ghrelin levels in children (median, 224.5; 25th to 75th percentile, 122.0-447.7 pg/ml) and adults (338.0; 238.0-512.0 pg/ml) were similar. SLB inhibited ghrelin levels in adults (263.0; 190.0-399.0 pg/ml). However, no change in ghrelin levels after SLB (206.5; 105.0-274.0 pg/ml) was recorded in children. Thus, food intake inhibits ghrelin secretion in adults but not in children. Ghrelin refractoriness to inhibition by food intake in children would reflect a peculiar functional profile of the ghrelin system in childhood.