Pseudohypoparathyroidism type Ia and pseudo-pseudohypoparathyroidism: the growing spectrum of GNAS inactivating mutations.

Pseudohypoparathyroidism (PHP) is a rare heterogeneous genetic disorder characterized by end-organ resistance to parathyroid hormone due to partial deficiency of the α subunit of the stimulatory G protein (Gsα), encoded by the GNAS gene. Heterozygous inactivating GNAS mutations lead to either PHP type Ia (PHP-Ia), when maternally inherited, or pseudo-pseudohypoparathroidism (PPHP), if paternally derived. Both diseases feature typical physical traits identified as Albright's hereditary osteodystrophy in the presence or absence of multihormone resistance, respectively. GNAS mutations are detected in 60-70% of affected subjects, most patients/families harbor private mutations and no genotype-phenotype correlation has been found to date. We investigated Gsα-coding GNAS exons in a large panel of PHP-Ia-PPHP patients collected over the past decade in the two Italian referring centers for PHP. Of 49 patients carrying GNAS mutations, we identified 15 novel mutations in 19 patients. No apparent correlation was found between clinical/biochemical data and results of molecular analysis. Furthermore, we summarized the current knowledge of GNAS molecular pathology and updated the GNAS-locus-specific database. These results further expand the spectrum of GNAS mutations associated with PHP/PPHP and underline the importance of identifying such genetic alterations to supplement clinical evaluation and genetic counseling.

The treatment of obesity in children and adolescents: consensus position statement of the Italian society of pediatric endocrinology and diabetology, Italian Society of Pediatrics and Italian Society of Pediatric Surgery.

This Position Statement updates the different components of the therapy of obesity (lifestyle intervention, drugs, and surgery) in children and adolescents, previously reported in the consensus position statement on pediatric obesity of the Italian Society of Pediatric Endocrinology and Diabetology and the Italian Society of Pediatrics. Lifestyle intervention is the first step of treatment. In children older than 12 years, pharmacotherapy is the second step, and bariatric surgery is the third one, in selected cases. Novelties are available in the field of the medical treatment of obesity. In particular, new drugs demonstrated their efficacy and safety and have been approved in adolescents. Moreover, several randomized control trials with other drugs are in process and it is likely that some of them will become available in the future. The increase of the portfolio of treatment options for obesity in children and adolescents is promising for a more effective treatment of this disorder.

Six novel mutations in the arginine vasopressin gene in 15 kindreds with autosomal dominant familial neurohypophyseal diabetes insipidus give further insight into the pathogenesis.

Autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is caused by postnatal arginine vasopressin (AVP) deficiency resulting from mutations in the AVP gene encoding the AVP pre-prohormone. To advance the understanding of adFNDI further, we have searched for mutations in the AVP gene in 15 unrelated kindreds in which diabetes insipidus appeared to be segregating. In nine kindreds, seven different previously described mutations were identified. In each of the other six kindreds, unique novel mutations were identified. Two of these (225A>G and 227G>A) change a nucleotide in the translation initiation codon of the signal peptide, whereas the other four (1797T>C, 1884G>A, 1907T>G, and 2112C>G) predict amino-acid substitutions in the neurophysin II moiety of the AVP prohormone, namely V67A (NP36), G96D (NP65), C104G (NP73), and C116W (NP85). Among these, the mutation predicting the V67A (NP36) substitution is remarkable. It affects a region of the neurophysin II not affected by any other mutations, produces only a minor change, and its inheritance suggests an incomplete penetrance. Our findings both confirm and further extend the mutation pattern that has emerged in adFNDI, suggesting that the mutations affect amino-acid residues known or reasonably presumed to be important for the proper folding and/or dimerization of the neurophysin II moiety of the AVP prohormone.