Effects of growth hormone treatment on adult height in severely short children with X-linked hypophosphatemic rickets.

BACKGROUND: We recently showed that a 3-year growth hormone (GH) treatment improves linear growth in severely short children with X-linked hypophosphatemic rickets (XLH). It is unknown if GH therapy increases adult height in XLH patients. METHODS: We carried out a follow-up analysis of a randomized controlled open-label GH study in short prepubertal children with XLH on phosphate and active vitamin D treatment. The changes in SD scores (SDS) of height, sitting height, leg and arm length, and sitting height index (i.e., the ratio between sitting height and height) were analyzed in 11 out of 16 patients followed-up until adult height. RESULTS: At baseline, XLH patients showed disproportionately short stature with reduced standardized height (-3.2 ± 0.6), sitting height (-1.7 ± 0.6), leg (-3.7 ± 0.7) and arm (-2.5 ± 0.8) length, and markedly elevated sitting height index (3.3 ± 0.6; each p < 0.01 versus healthy children). In GH-treated patients, adult height, sitting height, leg length, and arm length exceeded baseline values by 0.7 SDS, 1.7 SDS, 0.7 SDS, and 1.2 SDS respectively, although this was only significant for sitting height. In controls, no significant changes in linear body dimensions were noted. Adult height did not statistically differ between groups (-2.4 ± 0.7 vs -3.3 ± 1.2, p = 0.082). GH did not exaggerate body disproportion. CONCLUSIONS: Growth hormone treatment did not significantly increase adult height in this group of short children with XLH, which may be at least partly due to the small number of patients included in our study.

Genetic characteristics and long-term follow-up of 11 patients with congenital hyperinsulinism followed in a single center.

BACKGROUND: Congenital hyperinsulinism (CHI) is a rare disease with an estimated incidence of 1:40,000 live births. Here, we characterize 11 patients treated at Munich Children's Hospital Schwabing. METHODS: We analyzed data on birth, treatment and laboratory results including genetic testing and evaluated the long-term course with a follow-up visit. RESULTS: All patients had severe, diazoxide-(DZX)-resistant hypoglycemia, beginning immediately after birth. Two patients were treated by medical therapy, eight underwent subtotal pancreatectomy and one had a partial resection. Both patients who had medical therapy still suffer from occasional hypoglycemia. Six patients with subtotal pancreatectomy were affected by mild hypoglycemia. Seventy-five percent of patients who had surgical treatment developed diabetes mellitus (DM) at a median age of 10.5 (8-13) years. In 89% of patients with available genetic testing, mutations of the ABCC8 gene were detected. CONCLUSIONS: The majority of CHI-patients not responding to DZX underwent surgery. After subtotal pancreatectomy, patients typically developed diabetes around early puberty.

Somatic mosaicism underlies X-linked acrogigantism syndrome in sporadic male subjects.

Somatic mosaicism has been implicated as a causative mechanism in a number of genetic and genomic disorders. X-linked acrogigantism (XLAG) syndrome is a recently characterized genomic form of pediatric gigantism due to aggressive pituitary tumors that is caused by submicroscopic chromosome Xq26.3 duplications that include GPR101 We studied XLAG syndrome patients (n= 18) to determine if somatic mosaicism contributed to the genomic pathophysiology. Eighteen subjects with XLAG syndrome caused by Xq26.3 duplications were identified using high-definition array comparative genomic hybridization (HD-aCGH). We noted that males with XLAG had a decreased log2ratio (LR) compared with expected values, suggesting potential mosaicism, whereas females showed no such decrease. Compared with familial male XLAG cases, sporadic males had more marked evidence for mosaicism, with levels of Xq26.3 duplication between 16.1 and 53.8%. These characteristics were replicated using a novel, personalized breakpoint junction-specific quantification droplet digital polymerase chain reaction (ddPCR) technique. Using a separate ddPCR technique, we studied the feasibility of identifying XLAG syndrome cases in a distinct patient population of 64 unrelated subjects with acromegaly/gigantism, and identified one female gigantism patient who had had increased copy number variation (CNV) threshold for GPR101 that was subsequently diagnosed as having XLAG syndrome on HD-aCGH. Employing a combination of HD-aCGH and novel ddPCR approaches, we have demonstrated, for the first time, that XLAG syndrome can be caused by variable degrees of somatic mosaicism for duplications at chromosome Xq26.3. Somatic mosaicism was shown to occur in sporadic males but not in females with XLAG syndrome, although the clinical characteristics of the disease were similarly severe in both sexes.

First report of ectopic ACTH syndrome and PTHrP-induced hypercalcemia due to a hepatoblastoma in a child.

CONTEXT: Only occasionally, endocrine-active tumors develop directly from hepatic tissue, and may lead to paraneoplastic syndromes (PNS). PNS mostly accompany malignancy of adulthood and are exceedingly rare in children. PATIENT: A girl aged 6 years and 9 months presented with a 2-month history of rapidly progressive weight gain, abdominal distension, and polyuria/pollakiuria accompanied by short episodes of abdominal pain. She showed the typical clinical features of Cushing's syndrome and a huge hepatic mass. An abdominal computed tomography (CT) scan revealed a large liver tumor. Blood glucose and serum calcium were greatly elevated. DESIGN AND OBJECTIVE: Case report describing the causative relationship of the clinical findings. METHODS: Physical examination; ultrasound of the abdomen; CT scan of the abdomen and the chest; conventional X-rays; routine hematology; blood chemistry and multiple parameters of calcium and phosphorus metabolism; multisteroid analysis in serum and urine; adrenocortical stimulation and suppression tests; histopathological assessment of the resected tumor; immunohistochemistry for ACTH, beta-endorphin, corticotrophin-releasing hormone (CRH), and PTH-related peptide (PTHrP); electron microscopy of tumor cells; ACTH and CRH extraction from the tumor tissue; and clinical follow-up for more than 20 years. RESULTS: Giant hepatoblastoma (HB; approximately 1000 ml volume) of the right lobe of the liver with combined ectopic ACTH syndrome and PTHrP-induced tumor-associated hypercalcemia. Wide local excision and polychemotherapy led to complete reversal of the paraneoplastic phenotype. CONCLUSIONS: This is the first report of an endocrine-active HB causing both Cushing's syndrome and PTHrP-related 'humoral hypercalcemia of malignancy'. This information should be added to the well-known beta-human chorionic gonadotropin-related paraneoplastic effects of HB in children.

Daily insulin requirement of children and adolescents with type 1 diabetes: effect of age, gender, body mass index and mode of therapy.

DESIGN: The purpose of this study was to generate insulin dose (ID) percentiles for children and adolescents with type 1 diabetes mellitus (DM1) having the opportunity to assess this important parameter in relation to age and sex. METHODS: Daily IDs per weight (ID/kg) were recorded in 22,177 patients with DM1 (3-25 years of age, DM1 duration of more than 2 years, 48% female) and ID percentiles (ID-Perc) were created statistically. The ID-Perc were compared between male and female, and between multiple insulin injection therapy (MIT) and continuous s.c. insulin infusion (CSII). A multivariate regression analysis was performed for ID in the third year of DM1 with ID/kg, body weight, age, gender, and insulin delivery regimen as variables. RESULTS: The 50th ID-Perc (P50) varied among 0.67 IU/kg (age 3 years), 0.93 IU/kg (13 years), and 0.70 IU/kg (23 years) increasing from early childhood to adolescence and decreasing toward adulthood. Highest P50 ID was found at 12 years in females (0.94 IU/kg) and at 14 years in males (0.92 IU/kg). Using ICT, the ID was significantly higher compared with CSII (P50: 0.94 IU/kg versus 0.79 IU/kg at 13 years). In multivariate regression analysis, ID was significantly (P>0.001) associated with age, gender, and insulin delivery regime. CONCLUSION: The ID-Perc were significantly different during various periods of childhood and were influenced by gender, body weight, and insulin injection regimes. Therefore, the presented data 1) provide evidence to interpret individual ID in children and adolescents with DM1 and 2) more specifically identify children with unusually high (insulin resistance and non-compliance) or low (MODY and persistent remission) insulin requirement.