Formation of new chromatin domains determines pathogenicity of genomic duplications.

Chromosome conformation capture methods have identified subchromosomal structures of higher-order chromatin interactions called topologically associated domains (TADs) that are separated from each other by boundary regions. By subdividing the genome into discrete regulatory units, TADs restrict the contacts that enhancers establish with their target genes. However, the mechanisms that underlie partitioning of the genome into TADs remain poorly understood. Here we show by chromosome conformation capture (capture Hi-C and 4C-seq methods) that genomic duplications in patient cells and genetically modified mice can result in the formation of new chromatin domains (neo-TADs) and that this process determines their molecular pathology. Duplications of non-coding DNA within the mouse Sox9 TAD (intra-TAD) that cause female to male sex reversal in humans, showed increased contact of the duplicated regions within the TAD, but no change in the overall TAD structure. In contrast, overlapping duplications that extended over the next boundary into the neighbouring TAD (inter-TAD), resulted in the formation of a new chromatin domain (neo-TAD) that was isolated from the rest of the genome. As a consequence of this insulation, inter-TAD duplications had no phenotypic effect. However, incorporation of the next flanking gene, Kcnj2, in the neo-TAD resulted in ectopic contacts of Kcnj2 with the duplicated part of the Sox9 regulatory region, consecutive misexpression of Kcnj2, and a limb malformation phenotype. Our findings provide evidence that TADs are genomic regulatory units with a high degree of internal stability that can be sculptured by structural genomic variations. This process is important for the interpretation of copy number variations, as these variations are routinely detected in diagnostic tests for genetic disease and cancer. This finding also has relevance in an evolutionary setting because copy-number differences are thought to have a crucial role in the evolution of genome complexity.

Growth hormone excess in children with neurofibromatosis type-1 and optic glioma.

In children with neurofibromatosis type 1 (NF1) and optic pathways glioma (OPG), growth hormone (GH) excess has been rarely reported and mainly associated to central precocious puberty. The aim of our study is to evaluate the prevalence of GH excess, the association with central precocious puberty, the relation with tumor site and the evolution over time in a large cohort of children with NF1 and OPG. Sixty-four NF1 children with OPG were evaluated. Patients with stature and/or height velocity >2 SD for age were studied for GH secretion. Seven out of 64 children (10.9%) with NF1 and optic pathways glioma showed GH excess, isolated in 5 cases and associated to central precocious puberty in 2. All the children with GH excess had a tumor involving the chiasma. Children with GH excess underwent medical treatment with lanreotide and a minimum clinical/biochemical follow up of 2 years is reported. The present study demonstrates that GH excess should be considered as a relative frequent endocrine manifestation in NF1 patients, similarly to central precocious puberty. Therefore, these patients should undergo frequent accurate auxologic evaluations. On the other hand, an increase in height velocity in children with NF1, even despite normal ophthalmological exams, can suggest the presence of OPG and therefore represents an indication to perform brain MRI.

Nocturnal hypoglycaemia in ACTH and GH deficient children: role of continuous glucose monitoring.

OBJECTIVES: To evaluate the usefulness of continuous glucose monitoring (CGM) to identify nocturnal hypoglycaemia in children affected by combined ACTH and GH deficiency and to optimize the hydrocortisone replacement therapy in these patients. STUDY DESIGN: Eleven patients with ACTH and GH deficiency (five boys and six girls, age 1·6-16·8 years) underwent CGM for 36 h, including two nights. At least two consecutive glucose levels <2·78 mm were considered hypoglycaemic episodes. The differences in age and doses of hydrocortisone and recombinant human growth hormone (rhGH) between children with and without hypoglycaemia were analysed. The percentage of the glucose values <3·33 mm and the mean glucose levels were also evaluated. RESULTS: Continuous glucose monitoring demonstrated nocturnal hypoglycaemia lasting from 30 to 155 min (1·5% of the total monitoring time) in three cases (27%). No statistically significant differences in age and rhGH dose were observed between children with or without hypoglycaemia. Conversely, the difference in the hydrocortisone doses between the patients with and without hypoglycaemia resulted statistically significant (5·9 vs 8·5 mg/m²/day; P = 0·04). Eight patients presented glucose values less than 3·33 mm during 5% of the total monitoring time. Hydrocortisone dose showed significant positive linear relation with mean glucose level (r = 0·79, P = 0·0035) and inverse relation with time lags of glucose levels under 3·33 mm (r = -0·65, P = 0·03). CONCLUSIONS: Our study shows that CGM may represent a valuable tool to detect nocturnal asymptomatic hypoglycaemic episodes and optimize the hydrocortisone therapeutic regimen in children with ACTH and GH deficiency.

The natural history of the normal/mild elevated TSH serum levels in children and adolescents with Hashimoto's thyroiditis and isolated hyperthyrotropinaemia: a 3-year follow-up.

OBJECTIVE: The natural history of Hashimoto's thyroiditis (HT) and isolated hyperthyrotropinaemia (IH) is not well defined. We therefore studied the natural course of patients with HT and IH and looked for possible prognostic factors. DESIGN: This is retrospective cross-sectional study. PATIENTS: Three hundred and twenty-three patients with HT (88 boys and 235 girls) and 59 with IH (30 boys and 29 girls), mean age 9·9 ± 3·8 years were included in the study. When first examined, 236 of the children with HT had a normal TSH (G0) and in 87, it was elevated but <100% of the upper limit (G1). All IH subjects had elevated TSH. Potential risk factors for thyroid failure were evaluated after 3 years and included the presence or familiarity for endocrine/autoimmune diseases, premature birth, signs and symptoms of hypothyroidism, TSH levels, antithyroid antibodies and thyroid volume. RESULTS: HT: Of those with HT, 170 G0 patients remained stable, 31 moved to G1 and 35 to G2 (hypothyroidism). Thirty-six G1 children moved to G0, 17 remained stable and 34 moved to G2. Of patients with IH: 23 normalized, 28 remained stable and eight became overtly hypothyroid. In patients with HT, the presence of coeliac disease, elevated TSH and thyroid peroxidase antibodies (TPOAb) increased the risk of developing hypothyroidism by 4·0-, 3·4- and 3·5-fold, respectively. The increase in TSH levels during follow-up was strongly predictive of the development of hypothyroidism. In patients with IH, no predictive factor could be identified. CONCLUSIONS: Coeliac disease, elevated TSH and TPOAb at presentation and a progressive increase in TSH are predictive factors for thyroid failure in HT patients.

A CDKL5 mutated child with precocious puberty.

To date, 43 patients have been described with mutations in or involving the CDKL5 gene. The typical phenotype includes early-onset, often intractable epileptic seizures and severe mental retardation with very limited progress in psychomotor development. Most patients also show impaired social interaction with avoidance of eye-to-eye contact, and some clinical features reminiscent of Rett syndrome (RTT), including stereotypic hand movements, lack of purposeful hand use, acquired microcephaly, and generalized hypotonia. We report on the case of a 5-year-old girl with a de novo CDKL5 gene mutation who developed early puberty, which has not been described before.

Anti-Hypothalamus and Anti-Pituitary Auto-antibodies in ROHHAD Syndrome: Additional Evidence Supporting an Autoimmune Etiopathogenesis.

BACKGROUND: Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation (ROHHAD) is a very rare and complex pediatric syndrome characterized by altered hypothalamic thermal regulation, pain threshold, and respiratory control, hyperphagia with rapid weight gain and, often, hypothalamic-pituitary dysfunction. Its etiopathogenesis remains undetermined. We investigated the presence of alterations to target genes and hypothalamic-pituitary autoimmunity in a patient with -ROHHAD syndrome. METHODS: A 3-year-old girl presenting with obesity after rapid weight gain was diagnosed with ROHHAD syndrome based on clinical features and abnormal biochemical and functional testing results. Because of worsening of rapid symptoms and demonstration of oligoclonal bands on cerebrospinal fluid (CSF) analysis, she was treated with plasmapheresis, methylprednisolone, anti-CD20 monoclonal antibodies, and azathioprine. Despite initial partial clinical improvement, the patient soon died of cardiorespiratory arrest. Post-mortem, whole exome sequencing, high-resolution comparative genomic hybridization array, and optimized indirect immunofluorescence (IIF) analysis were performed on blood and CSF. RESULTS: No putative causative genomic variants compatible with dominant or recessive inheritance nor clinically significant structural rearrangement were detected. IIF on serum and CSF demonstrated the presence of anti-pituitary and anti-hypothalamus autoantibodies. CONCLUSIONS: These findings support the involvement of autoimmunity in ROHHAD syndrome. However, response to immunosuppressive treatment was only transient and the patient died. Further cases are required to define the complex disease pathogenesis.

Thyroid morphology and subclinical hypothyroidism in children and adolescents with Williams syndrome.

OBJECTIVE: To verify the prevalence of morpho-volumetric and functional thyroid abnormalities in young patients with Williams syndrome (WS). STUDY DESIGN: Ninety-two patients with WS (49 boys and 43 girls, 0.2-17.2 years of age) underwent evaluation of thyroid function by means of thyroid-stimulating hormone (TSH), fT3, and fT4 measurement. Thyroid ultrasonography was performed in 37 patients. Thyroid antibodies (thyroid peroxidase and thyroglobulin) were measured in all patients with abnormal thyroid function tests. RESULTS: None of our patients had overt hypothyroidism; 29 patients (31.5%) had subclinical hypothyroidism. Thyroid antibodies were absent in all patients. The prevalence of patients with subclinical hypothyroidism was significantly higher in the younger patients. Ultrasonography revealed morphological or volumetric abnormalities of the thyroid gland in 67.5% of patients; these abnormalities were more frequently observed in the older children. CONCLUSIONS: Subclinical hypothyroidism is a frequent but stable finding in young children with WS. The great majority of patients with WS >10 years, either with normal or hypoplastic thyroid, have normal thyroid function. Therefore, we suggest yearly monitoring of thyroid function and sonographic studies at least once in patients with WS. Treatment should be reserved for the patients with overt hypothyroidism or for those whose thyroid function shows signs of progressive deterioration.

Non-conventional use of growth hormone therapy.

UNLABELLED: Human growth hormone therapy is allowed in certain clinical conditions according to national healthcare criteria. Growth hormone, however, produces a wide spectrum of effects. Linear growth is only one of the many expected results, and there are interesting possibilities to explore which could provide additional means of improving the quality of life for the ever-increasing numbers of chronic paediatric patients. CONCLUSION: In this review, we discuss the rationale for and possibility of using growth hormone therapy in some conditions not strictly related to growth hormone deficiency.

Long-term first line medical treatment in a 4-year-old girl with Xq26.3 microduplication-negative somatotropinoma. Case report and literature review.

Growth hormone (GH) secreting adenoma represents a therapeutic challenge in childhood. Because of its rarity no treatment guidelines are available and pediatric management often results from recommendations issued for adults. We report a case of a 4-year-old girl with somatotropinoma successfully treated with only medical treatment. She presented with tall stature and history of growth acceleration. Imaging and laboratory confirmed the diagnosis of GH secreting macroadenoma. She started medical treatment with a somatostatin analogue and a dopamine agonist. During an 8-year follow-up period, a good clinical control of the disease and a shrinkage of the adenoma have been demonstrated. At the last observation she achieved normal near-adult height and pubertal development. According to our experience and limited literature evidences, first line treatment with somatostatin analogues can be attempted in patients with somatotropinoma. This approach seems to be able to control the clinical course of the disease, allowing to postpone transphenoidal surgery to adult age or to avoid it.

Congenital primary adrenal insufficiency and selective aldosterone defects presenting as salt-wasting in infancy: a single center 10-year experience.

BACKGROUND: Salt-wasting represents a relatively common cause of emergency admission in infants and may result in life-threatening complications. Neonatal kidneys show low glomerular filtration rate and immaturity of the distal nephron leading to reduced ability to concentrate urine. METHODS: A retrospective chart review was conducted for infants hospitalized in a single Institution from 1(st) January 2006 to 31(st) December 2015. The selection criterion was represented by the referral to the Endocrinology Unit for hyponatremia (serum sodium <130 mEq/L) of suspected endocrine origin at admission. RESULTS: Fifty-one infants were identified. In nine infants (17.6 %) hyponatremia was related to unrecognized chronic gastrointestinal or renal salt losses or reduced sodium intake. In 10 infants (19.6 %) hyponatremia was related to central nervous system diseases. In 19 patients (37.3 %) the final diagnosis was congenital adrenal hyperplasia (CAH). CAH was related to 21-hydroxylase deficiency in 18 patients, and to 3ß-Hydroxysteroid dehydrogenase (3ßHSD) deficiency in one patient. Thirteen patients (25.5 %) were affected by different non-CAH salt-wasting forms of adrenal origin. Four familial cases of X-linked adrenal hypoplasia congenita due to NROB1 gene mutation were identified. Two unrelated girls showed aldosterone synthase deficiency due to mutation of the CYP11B2 gene. Two unrelated infants were affected by familial glucocorticoid deficiency due to MC2R gene mutations. One girl showed pseudohypoaldosteronism related to mutations of the SCNN1G gene encoding for the epithelial sodium channel. Transient pseudohypoaldosteronism was identified in two patients with renal malformations. In two infants the genetic aetiology was not identified. CONCLUSIONS: Emergency management of infants presenting with salt wasting requires correction of water losses and treatment of electrolyte imbalances. Nevertheless, the differential diagnosis may be difficult in emergency settings, and sometimes hospitalized infants presenting with salt-wasting are immediately started on steroid therapy to avoid life-threatening complications, before the correct diagnosis is reached. Physicians involved in the management of infants with salt-wasting of suspected hormonal origin should remember that, whenever practicable, a blood sample for the essential hormonal investigations should be collected before starting steroid therapy, to guide the subsequent diagnostic procedures and in particular to address the analysis of candidate genes.

Pituicytoma and Cushing's Disease in a 7-Year-Old Girl: A Mere Coincidence?

Pituicytoma is a tumor extremely rare in childhood, with only 4 cases reported in literature. It is thought to arise from the specialized glial elements called "pituicytes." The association of pituicytoma and Cushing's disease (CD) has been described only once so far, in an adult patient. A 7-year-old girl was referred for clinical signs of hypercortisolism, and a diagnosis of CD was made. MRI revealed 2 pathologic areas in the pituitary gland. The patient underwent surgery, with microscopic transsphenoidal approach, and a well-circumscribed area of pathologic tissue was identified and removed. Surprisingly, histologic and immunohistochemical study provided unequivocal evidence of pituicytoma. No pituitary adenoma could be identified. For persistent hypercortisolism, the patient necessitated transsphenoidal endoscopic reintervention and 2 other lesions were removed. By immunohistological examination, these lesions were confirmed to be corticotropin-secreting adenoma. Unfortunately, there was no postoperative decrease in corticotropin and cortisol levels, and the patient underwent bilateral laparoscopic adrenalectomy. Considering that we report a second case of association of pituicytoma and corticotropin-secreting adenoma, that CD is infrequent, and pituicytoma is extremely rare in childhood, the coexistence of these 2 tumors should not be considered a mere coincidence. To date, there is no conclusive evidence about the origin of these different subtypes of pituitary tumors. This case supports the hypothesis that these tumors share a common progenitor cell, which could be the folliculostellate cell.

Growth and pubertal growth spurt in dysmorphic syndromes.

We describe peculiar aspects of growth and the pubertal growth spurt in dysmorphic syndromes, focusing our attention on the accelerated pubertal growth pattern in some dysmorphic syndromes leading to short stature (DSS). A normal pubertal growth spurt was observed in other dysmorphic syndromes leading to overgrowth (ODS).

Autosomal-dominant isolated growth hormone deficiency (IGHD type II) with normal GH-1 gene.

BACKGROUND: Autosomal-dominant isolated GH deficiency (IGHD) is a rare disorder that is commonly believed to be due to heterozygous mutations in the GH-1 gene (GH-1). These mutations cause the production of a protein that affects the release of the product of the normal allele. Rarely, heterozygous mutations in the gene encoding for HESX-1 gene (HESX-1) may cause autosomal-dominant IGHD, with penetrance that has been shown to be variable in both humans and mice. SUBJECTS AND METHODS: We have sequenced the whole GH-1 in the index cases of 30 families with autosomal-dominant IGHD. In all the families other possible causes of GH deficiency and other pituitary hormones deficits were excluded. We here describe the clinical, biochemical and radiological picture of the families without GH-1 mutations. In these families, we also sequenced the HESX-1. RESULTS: The index cases of the five families with autosomal-dominant IGHD had normal GH-1, including the intronic sequences. They had no HESX-1 mutations. CONCLUSION: This study shows that GH-1 mutations are absent in 5/30 (16.6%) of the families with autosomal-dominant IGHD and raises the possibility that mutations in other gene(s) may be involved in IGHD with this mode of transmission.