Autosomal dominant hypocalcemia due to a truncation in the C-tail of the calcium-sensing receptor.

Autosomal Dominant Hypocalcemia (ADH) is an endocrine disorder due to activating mutations of the calcium-sensing receptor (CASR) gene. We report on a young boy who presented low serum calcium with hypercalciuria, hyperphosphatemia and low serum concentration of parathyroid hormone, not accompanied by classic clinical signs of hypocalcemia. Treatment with calcitriol and calcium did not normalize serum calcium and renal calcium excretion. The use of thiazide diuretics slightly reduced calciuria. Despite high calcium excretion, no signs of nephrocalcinosis were detected. The patient had a prolonged Q-T interval at ECG, which did not normalize during treatment. PCR amplification of CASR coding sequence and direct sequencing of PCR products. showed a novel heterozygous deletion of a cytosine (c.2682delC), responsible for a frameshift (p.S895Pfs*44) and a premature stop codon resulting in a truncation of the CaSR's C-tail. Functional studies indicated increased activity of mutant receptor compared to the wild-type.

Dissection of partial 21q monosomy in different phenotypes: clinical and molecular characterization of five cases and review of the literature.

BACKGROUND: Partial deletion of chromosome 21q is a very rare chromosomal abnormality associated with highly variable phenotypes, such as facial dysmorphic features, heart defects, seizures, psychomotor delay, and severe to mild intellectual disability, depending on the location and size of deletions. So far, three broad deletion regions of 21q have been correlated with the clinical phenotype. RESULTS: We described the clinical and genetic features of three family members (father and two siblings) and other two unrelated patients with very wide range in age of diagnosis. All of them showed intellectual disability with very variable symptoms, from mild to severe, and carried 21q interstitial deletions with different sizes and position, as detected by conventional karyotype and array-CGH. CONCLUSIONS: Our study provided additional cases of partial 21q deletions, allowing to better delineate the genotype-phenotype correlations. In contrast to previous observations, we showed that deletions of the 21q proximal region are not necessarily associated with severe phenotypes and, therefore, that mild phenotypes are not exclusively related to distal deletions. To the best of our knowledge, this is the first report showing 21q deletions in adult patients associated with mild phenotypes, mainly consisting of neurobehavioral abnormalities, such as obsessive-compulsive disorders, poor social interactions and vulnerability to psychosis.

Idiopathic central precocious puberty associated with 11 mb de novo distal deletion of the chromosome 9 short arm.

We report a girl with a de novo distal deletion of 9p affected by idiopathic central precocious puberty and intellectual disability. Genome-wide array-CGH revealed a terminal deletion of about 11 Mb, allowing to define her karyotype as 46; XX, del(9)(p23-pter). To our knowledge, this is the second reported case of precocious puberty associated with 9p distal deletion. A third case associates precocious puberty with a more proximal 9p deletion del(9)(p12p13,3). In our case, more than 40 genes were encompassed in the deleted region, among which, DMRT1 which is gonad-specific and has a sexually dimorphic expression pattern and ERMP1 which is required in rats for the organization of somatic cells and oocytes into discrete follicular structures. Although we cannot exclude that precocious puberty in our del(9p) patient is a coincidental finding, the report of the other two patients with 9p deletions and precocious puberty indeed suggests a causative relationship.

Noonan syndrome associated with both a new Jnk-activating familial SOS1 and a de novo RAF1 mutations.

Noonan syndrome is a genetic condition characterized by congenital heart defects, short stature, and characteristic facial features. Familial or de novo mutations in PTPN11, RAF1, SOS1, KRAS, and NRAS are responsible for 60-75% of the cases, thus, additional genes are expected to be involved in the pathogenesis. In addition, the genotype-phenotype correlation has been hindered by the highly variable expressivity of the disease. For all these reasons, expanding the genotyped and clinically evaluated case numbers will benefit the clinical community. A mutation analysis has been performed on RAF1, SOS1, and GRB2, in 24 patients previously found to be negative for PTPN11 and KRAS mutations. We identified four mutations in SOS1 and one in RAF1, while no GRB2 variants have been found. Interestingly, the RAF1 mutation was present in a patient also carrying a newly identified p.R497Q familial SOS1 mutation, segregating with a typical Noonan Syndrome SOS1 cutaneous phenotype. Functional analysis demonstrated that the R497Q SOS1 mutation leads to Jnk activation, but has no effect on the Ras effector Erk1. We propose that this variant might contribute to the onset of the peculiar ectodermal traits displayed by the propositus amidst the more classical Noonan syndrome presentation. To our knowledge, this is the first reported case of a patient harboring mutations in two genes, with an involvement of both Ras and Rac1 pathways, indicating that SOS1 may have a role of modifier gene that might contribute the variable expressivity of the disease, evidencing a genotype-phenotype correlation in the family.

Recombinant human GH replacement therapy in children with pseudohypoparathyroidism type Ia: first study on the effect on growth.

CONTEXT: Since the identification of GH deficiency due to resistance to GHRH in patients with pseudohypoparathyroidism type Ia (PHP-Ia), no study investigated the effects of recombinant human GH (rhGH) therapy on height velocity (HV) in these patients. OBJECTIVES, PATIENTS AND METHODS: To address this question, eight prepubertal PHP-Ia children with GH deficiency (seven girls and one boy, aged 5.8-12 yr) underwent a 3- to 8-yr treatment with rhGH. Height and HV were measured before and at 6-month intervals during therapy. Nine sex- and age-matched children with idiopathic GH deficiency were monitored during rhGH therapy for comparison. RESULTS: In PHP-Ia children, height sd scores increased from -2.4 ± 0.58 to -1.8 ± 0.47 (P = 0.04) after 12 months, this increase being maintained after the second (-1.6 ± 0.6) and third (-1.15 ± 0.6) year of therapy, similarly to what recorded in children with idiopathic GH deficiency. The HV and HV sd scores after 3 yr maintained a significant increase from 3.5 ± 0.6 to 7.0 ± 0.9 cm/yr (P < 0.0001) and from -2.8 ± 0.8 to +2.2 ± 1.0 (P < 0.0001), respectively. Six patients treated for 4-8 yr had a reduced pubertal spurt and did not improve their near-adult height, with the only exception of one patient in whom estrogen production was blocked by GnRH analogs. CONCLUSIONS: We report the first study on the efficacy of rhGH replacement therapy in prepubertal children with PHP-Ia and provide indication that treatment of GH deficiency should be started soon due to the rather limited time window for a potentially effective therapy.

Neurofibromatosis type 1 with external genitalia involvement presentation of 4 patients.

Genitourinary neurofibromas with clitoral involvement in neurofibromatosis type 1 are rare, and even more infrequent are the neurofibromas involving genitalia in males. The most frequent presenting sign of neurofibroma in females is clitoromegaly with pseudopenis, and enlarged penis is the most common sign in males. Labium majus neurofibroma not associated with clitoral involvement is extremely rare. Magnetic resonance imaging demonstration of the neurofibromas has seldom been reported. We report 4 children, 3 girls and 1 boy, with plexiform neurofibromas involving the external genitalia. Three of the 4 patients had histologic confirmation of neurofibroma. Two girls with clitoral hypertrophy had a neurofibroma that infiltrated the clitoris and extended unilaterally to the lower bladder wall. One girl had a plexiform neurofibroma that affected a labium. One boy with asymmetric penile hypertrophy since 2 years of age and ipsilateral gluteal hypertrophy had plexiform neurofibromas that extended between the left lumbogluteal and penile regions, infiltrating the left rectum wall and bladder with compression of both structures, the left prostate, and the left half of the cavernous corpi with hypertrophy of this part and asymmetry of the penis. Magnetic resonance imaging demonstrated in all patients that external genitalia and plexiform neurofibroma formed images of nondetachable structures. However, hermaphroditism was discarded by chromosomal study in all 3 girls before ratifying the diagnosis of external genitalia neurofibroma.

Adult height in children with short stature and idiopathic delayed puberty after different management.

By retrospectively collecting data from nine Italian centres of pediatric endocrinology, we assessed the different management and final outcome of children with short stature and idiopathic delayed puberty. Data were obtained in 77 patients (54 males, 23 females) diagnosed and followed-up in the various centres during the last 15 years. Inclusion criteria were short stature at initial observation and idiopathic delayed puberty diagnosed during follow-up. At first observation, age was 13.8 +/- 1.0 years and height standard deviation score (SDS) was -2.6 +/- 0.6 in males. In females age was 13.1 +/- 0.9 years and height SDS -2.6 +/- 0.4. Local diagnostic and therapeutic protocols included testing for growth-hormone deficiency (six centres) and treatment in case of deficiency or, in the remaining centres, testosterone or no treatment in males, and no treatment in females. At diagnosis, both in males and in females, the auxological features (height SDS, target height SDS and bone age delay) were similar in the patients treated with growth hormone, testosterone or not treated. Overall 32 patients received growth hormone (25 males, 7 females), 33 no treatment (17 males, 16 females) and 12 testosterone. There was no difference in the adult height of males and females in the different treatment groups. In males there were no differences between adult and target height SDSs (growth hormone-treated 0.31 +/- 0.79, untreated 0.10 +/- 0.82, testosterone-treated 0.05 +/- 0.95), between adult and initial height SDSs (growth hormone-treated 1.70 +/- 0.93, untreated 1.55 +/- 0.92, testosterone-treated 1.53 +/- 1.43) and percentage of subjects with adult height above target height. In females, there were no differences between adult and target height SDSs (growth hormone-treated -0.49 +/- 1.13; untreated 0.10 +/- 0.97) and between adult and initial height SDSs (growth hormone-treated 1.76 +/- 0.92; untreated 1.77 +/- 0.98), whereas a significantly higher percentage of patients remained below target height in the growth hormone-treated group (6/7, 85.7% vs 5/11, 31.3%) (P = 0.02). In conclusion, the diagnostic and therapeutic management of the patients with short stature and delayed puberty is different among Italian pediatric endocrinologists. Our data do not support the usefulness of growth-hormone therapy in improving adult height in subjects with short stature and delayed puberty, particularly in the female sex.

Genetic analysis and evaluation of resistance to thyrotropin and growth hormone-releasing hormone in pseudohypoparathyroidism type Ib.

CONTEXT: Pseudohypoparathyroidism (PHP) types Ia and Ib, are caused by mutations in GNAS exons 1-13 and GNAS methylation defects, respectively. PHP-Ia patients show Albright hereditary osteodystrophy (AHO) and resistance toward PTH and additional hormones, whereas PHP-Ib patients do not have AHO and hormone resistance is limited to PTH and, as reported in one paper, TSH. No study addressed the question of GH deficiency in PHP-Ib patients. OBJECTIVES: The objective of the study was to screen patients with clinically diagnosed PHP-Ib for genetic defects and investigate the presence of resistance to TSH and GHRH. PATIENTS/METHODS: We investigated GNAS differential methylation and STX16 microdeletions in genomic DNA from 10 patients with clinical diagnosis of sporadic PHP-Ib, i.e. PTH resistance without AHO. Resistance to GHRH was assessed by GH response to GHRH plus arginine. Thyroid function and ultrasonography were also evaluated. RESULTS: Molecular analysis showed GNAS cluster imprinting defects in all PHP-Ib patients and the first de novo STX16 deletion in one apparently sporadic patient. Subclinical or clinical hypothyroidism due to resistance to TSH was present in nine of 10 patients, whereas a preserved GH response to a GHRH plus arginine test was present in all patients, with one exception. CONCLUSIONS: We report the first molecular analysis of Italian patients with PHP-Ib. Clinical investigation shows that, like PHP-Ia patients, PHP-Ib patients are resistant to TSH, whereas they maintain a normal responsiveness to GHRH, at variance with PHP-Ia patients. These data provide new information on this rare disease and emphasize the clinical heterogeneity of genetic defects within GNAS.

Helicobacter pylori infection and autoimmune thyroid disease in young patients: the disadvantage of carrying the human leukocyte antigen-DRB1*0301 allele.

CONTEXT AND OBJECTIVE: Pathogenesis of autoimmune thyroid disease (ATD) is multifactorial. Helicobacter pylori (Hp) infection has been proposed to be involved in nongastrointestinal conditions and reported more frequently in ATD adult patients. We evaluated the prevalence of Hp antibodies in young ATD patients and investigated the possibility that a susceptible immunogenetic profile could influence the development of ATD in subjects with Hp infection. SUBJECTS AND METHODS: We retrospectively studied 90 children with ATD (median age 11.2 yr), 70 age- and sex-matched healthy subjects as controls, and 65 patients with Turner syndrome (median age 18.8 yr). Antibodies to Hp were determined at diagnosis in ATD patients and, in Turner patients, at the last control in cases without ATD and before the appearance of thyroid autoantibodies in the others. Serological and molecular human leukocyte antigen (HLA) typing for classes I and II polymorphisms was performed. RESULTS: Prevalence of positive Hp serology resulted significantly higher in ATD patients than controls (P = 0.032). No association was found between individual HLA alleles and Hp serology. HLA-A1, B8, and DRB1*0301 were found significantly associated with ATD. A significant interaction between HLA-DRB1*0301 and Hp infection was present in ATD patients and not controls (P = 0.007), suggesting that the copresence of these two factors might favor ATD development. A similar phenomenon was observed in Turner syndrome patients (P = 0.02; cumulative Mantel test, P = 0.0001). CONCLUSIONS: Another target of Hp-elicited immune inflammatory response might be the thyroid gland in subjects with a peculiar immunogenetic profile so that ATD may be a consequence. Our findings suggest the opportunity of eradicating Hp infection in children with ATD and/or susceptible HLA alleles.

Selecting girls with precocious puberty for brain imaging: validation of European evidence-based diagnosis rule.

OBJECTIVES: To test the sensitivities of recently published American recommendations predicting occult intracranial lesion (OICL) in girls with central precocious puberty (CPP), and to validate a previously derived diagnosis rule predicting OICL based on age at puberty onset and estradiol (E2) level. STUDY DESIGN: A retrospective, multicenter, hospital-based, cohort study was performed, including all girls with CPP seen in 7 centers in 6 European countries during given periods. American recommendations and the previously derived diagnosis rule were tested. RESULTS: Girls with CPP (n=443), including 35 with OICL, were recruited. American recommendations did not identify all OICL. Previously identified independent risk factors for OICL were confirmed: age <6 years (adjusted odds ratio 20.5; 95% CI, 8.1-52.1) and E2 >45th percentile (3.0; 95% CI, 1.3-7.1). The previously derived diagnosis rule had 100% sensitivity (95% CI, 90-100): all girls with OICL had either an age <6 years or an E2 level >45th percentile. The specificity was 39% (95% CI, 34-44). CONCLUSIONS: American recommendations do not seem safe to select European girls with CPP who require brain imaging. In settings where systematic brain imaging is not possible, the proposed diagnosis rule could safely help to avoid more than one third of unnecessary brain imaging.

A novel nonsense mutation in the Pit-1 gene: evidence for a gene dosage effect.

The POU transcription factor Pit-1 functions in the development of somatotrophs, lactotrophs, and thyrotrophs of the anterior pituitary gland. It also plays a role in cell-specific gene expression and regulation of the gene products from these cell types, GH, prolactin, and TSH, respectively. In the present report we studied a patient with severe growth failure. Provocative studies revealed undetectable GH, prolactin, and TSH levels, and her pituitary gland was hypoplastic on magnetic resonance imaging. She had a novel homozygous nonsense mutation in the 3' end of the first alpha-helix of the POU-specific domain of the Pit-1 gene. This mutation results in a truncated protein with loss of most of the Pit-1 DNA-binding domains. Interestingly, her parents, who each have one mutant allele, have evidence of mild endocrine dysfunction. Thus, two normal copies of the Pit-1 gene appear necessary for full Pit-1 gene function.

The acid-labile subunit of human ternary insulin-like growth factor-binding protein complex in girls with central precocious puberty before and during gonadotropin-releasing hormone analog therapy.

The aim of the study was to evaluate serum acid-labile subunit (ALS) concentrations and their relationship with other parameters of the human ternary IGF-I-binding protein (IGFBP) complex in girls with central precocious puberty (CPP) before and after pharmacological arrest of puberty. We studied serum ALS, free IGF-I, total IGF-I, IGFBP-3 levels and IGFBP-3 protease activity in 13 girls, aged 1.6-7.8 yr (mean, 5.9 +/- 2.2), diagnosed as having CPP before and after 6 and 12 months of GnRH analog (GnRHa) therapy. The ALS SD score before treatment was high (1.4 +/- 0.72) and decreased significantly after 6 and 12 months of GnRHa therapy [0.4 +/- 0.54 (P < 0.01) and -0.4 +/- 0.61 (P < 0.01), respectively]. Serum IGF-I and IGFBP-3 were also increased before treatment, but both of these factors remained elevated after 6 and 12 months of GnRH-A therapy [IGF-I SD score, 3.20 +/- 1.64, 2.92 +/- 1.82, and 3.68 +/- 1.94 (P = NS), respectively; IGFBP-3 SD score, 1.02 +/- 0.53, 0.94 +/- 0.68, and 1.22 +/- 0.87 (P = NS), respectively]. Serum free IGF-I levels and IGFBP-3 proteolytic activity did not vary significantly from their pretreatment values during GnRHa therapy. In conclusion, serum ALS levels were elevated in girls with CPP and decreased significantly during the first year of GnRHa therapy. Serum IGF-I and IGFBP-3 levels were also increased before therapy, but their levels were not influenced by treatment. The ALS decrease seems to be the sole GH-dependent factor that parallels the decreases in steroid levels and growth velocity during GnRHa therapy.

Do reduced levels of steroid 21-hydroxylase confer a survival advantage in fetuses affected by sex chromosome aberrations?

We investigated whether molecular defects in the CYP21 gene were detectable in two common sex chromosome aberrations, the Turner and the Klinefelter syndromes. We found abnormal 17-hydroxyprogesterone levels after adrenal stimulation in 26/60 (43.3%) patients affected by these chromosome aberrations, as compared with only 11/68 (16.2%) normal controls (P=0.0014, odds ratio 4.0). Screening of the CYP21 gene identified a single Val281Leu missense mutation in exon 7 in 9/63 (14.3%) of the patients, all nine of whom were heterozygote carriers; the mutation frequency was significantly higher than in the general population (P=0.007, odds ratio=3.5). The hormonal and molecular data indicate that these common sex chromosome aberrations are associated with a remarkably high frequency of steroidogenic defects. It may be hypothesised that reduced levels of steroid 21-hydroxylase could confer a survival advantage, leading to a successful pregnancy.