Annalisa Calcagno

Central Diabetes Insipidus in Children and Young Adults: Etiological Diagnosis and Long-Term Outcome of Idiopathic Cases

CONTEXT Central diabetes insipidus (CDI) is considered idiopathic in 20% to 50% of affected subjects. OBJECTIVE The purpose of this study was to determine whether a systematic diagnostic workup could achieve better etiologic diagnosis in children and adolescents presenting with polyuria and polydipsia. DESIGN AND SETTING This is a prospective study conducted at a tertiary referral center. Patients underwent clinical and endocrine evaluations every 6 months and neuroimaging every 6 months for 2 years and yearly for 3 years. Endocrine function and neuroimaging were also reassessed after adult height achievement. PARTICIPANTS A total of 85 consecutive patients with CDI were enrolled at a median age of 7.5 years; those with idiopathic CDI were stratified based on pituitary stalk thickness. MAIN OUTCOME MEASURES To establish the etiology of CDI, we determined the time lag between its onset and the specific diagnosis, the long-term impact on pituitary function, and the overall long-term outcomes. RESULTS Of the subjects, 24 (28.2%) received an etiologic diagnosis at presentation and 11 (13%) within 2.5 years (n = 7 germinomas and n = 4 Langerhans cell histiocytosis), 7 (8.2%) were lost to follow-up, and 43 (50.6%) were considered to have idiopathic disease and were followed until the median age of 17.3 years. Neuroimaging identified 40 of 43 patients with self-limited inflammatory/autoimmune pituitary stalk thickness within the first 6 months, the severity of which was significantly correlated to pituitary dysfunction. The probability of >10-year-survival without an anterior pituitary defect was related to the severity of pituitary stalk thickness, and 53% showed permanent anterior pituitary defects. Three patients developed Langerhans cell histiocytosis and 1 developed Hodgkin lymphoma after a median of 9 and 13 years, respectively. CONCLUSIONS A diagnostic etiology was achieved in 96% of patients with CDI. Risk stratification based on the degree of pituitary stalk thickness is of prognostic value for long-term outcomes including permanent pituitary dysfunction. New guidance is provided for the management of these patients.

Reassessment of the Growth Hormone Status in Young Adults with Childhood-Onset Growth Hormone Deficiency: Reappraisal of Insulin Tolerance Testing

CONTEXT The 2007 Consensus Statement suggested a peak GH cutoff to insulin tolerance test (ITT) of less than 6 microg/liter in the diagnosis of permanent GH deficiency (GHD) in young adults with childhood-onset GHD (COGHD), although further validation was recommended. OBJECTIVE The aim of the study was to evaluate the accuracy of ITT, mean 12-h spontaneous nocturnal GH (SNGH), and IGF-I in the definition of permanent GHD. DESIGN AND SETTING The study was conducted in two Pediatric Endocrinology Centers. PATIENTS AND METHODS ITT, 12-h SNGH, and IGF-I were evaluated as single or combined tests in 79 subjects with COGHD (median age, 18.0 yr). The cohort consisted of 48 subjects with isolated GHD or one additional pituitary defect and normal MRI or anterior pituitary hypoplasia (group LLGHD, low likelihood GHD), and 31 subjects with structural hypothalamic-pituitary abnormalities or multiple pituitary hormone deficiencies (group HLGHD, high likelihood GHD). RESULTS Receiver operating characteristic analysis showed the best diagnostic accuracy for peak GH cutoffs to ITT of 5.62 microg/liter or less [sensitivity, 77.4%; specificity, 93.8%; area under the curve (AUC) = 0.92], mean 12-h SNGH of 1.20 microg/liter or less (sensitivity, 90.3%; specificity, 89.6%; AUC = 0.93), and IGF-I of -2.83 sd score or less (sensitivity, 80.7%; specificity, 95.7%; AUC = 0.93). Seven patients in group HLGHD showed a peak GH to ITT above 5.62 microg/liter, but a median IGF-I that was significantly lower than that of group LLGHD (-3.30 vs. -0.73 sd score; P = 0.0001). Peak GH to ITT of 3.6 microg/liter or less and arginine of 3.1 microg/liter or less at childhood diagnosis can predict a future permanent GHD condition. CONCLUSIONS The adopted peak GH to ITT below 5.62 microg/liter is an accurate diagnostic cutoff point for HLGHD in young adults with COGHD. In addition, IGF-I is a reliable marker providing information about the severity of GHD. Careful follow-up is required for subjects with discordant ITT and IGF-I results.

The Accuracy of the Glucagon Test Compared to the Insulin Tolerance Test in the Diagnosis of Adrenal Insufficiency in Young Children with Growth Hormone Deficiency

CONTEXT The accuracy of the glucagon test in the diagnosis of central adrenal insufficiency in young children has not yet been definitively established. OBJECTIVE The aim of this study was to investigate the diagnostic accuracy of the glucagon test as an alternative to the insulin tolerance test (ITT) in children with GH deficiency under 6 yr of age. DESIGN AND SETTING This was a prospective study conducted in two Pediatric Endocrinology Centers. PATIENTS AND METHODS Forty-eight children (median age, 4.2 yr) with GH deficiency confirmed by a peak GH to ITT and arginine less than 10 microg/liter were enrolled: 24 with normal hypothalamic-pituitary anatomy, seven with isolated anterior pituitary hypoplasia, and 17 with structural hypothalamic-pituitary abnormalities at magnetic resonance imaging. Twelve subjects had central adrenal insufficiency defined by a peak cortisol response of less than 20 microg/dl to ITT. All children underwent a glucagon stimulation test with blood sampling for cortisol and glucose (time 0 to 180 min) after the im administration of 30 microg/kg of glucagon. RESULTS The mean peak cortisol after glucagon was not significantly different from that obtained after ITT in the whole cohort (25.9 vs. 26.0 microg/dl; P = 0.908), and it was significantly reduced in patients with structural hypothalamic-pituitary abnormalities (P < 0.001). Receiver operating characteristic curve analysis showed that the best diagnostic accuracy was obtained with a peak cortisol cutoff to glucagon of 14.6 microg/dl (sensitivity, 66.67%; specificity, 100%; area under the curve = 0.91; 95% confidence interval, 0.82-0.99). Using this cutoff, 91.67% of the patients were correctly classified. CONCLUSIONS This study shows that glucagon is an accurate and safe diagnostic test for adrenal function in young children who are at risk for adrenal insufficiency.

Classical and non-classical causes of GH deficiency in the paediatric age

Growth hormone deficiency (GHD) may result from a failure of hypothalamic GHRH production or release, from congenital disorders of pituitary development, or from central nervous system insults including tumors, surgery, trauma, radiation or infiltration from inflammatory diseases. Idiopathic, isolated GHD is the most common sporadic form of hypopituitarism. GHD may also occur in combination with other pituitary hormone deficiencies, and is often referred to as hypopituitarism, combined pituitary hormone deficiency (CPHD), multiple pituitary hormone deficiency (MPHD) or panhypopituitarism. Children without any identifiable cause of their GHD are commonly labeled as having idiopathic hypopituitarism. MRI imaging is the technique of choice in the diagnosis of children with hypopituitarism. Marked differences in MRI pituitary gland morphology suggest different etiologies of GHD and different prognoses. Pituitary stalk agenesis and ectopic posterior pituitary (EPP) are specific markers of permanent GHD, and patients with these MRI findings show a different clinical and endocrine outcome compared to those with normal pituitary anatomy or hypoplastic pituitary alone. Furthermore, the classic triad of ectopic posterior pituitary gland, pituitary stalk hypoplasia/agenesis, and anterior pituitary gland hypoplasia is generally associated with permanent GHD. T2 DRIVE images aid in the identification of pituitary stalk without the use of contrast medium administration. Future developments in imaging techniques will undoubtedly reveal additional insights. Mutations in a number of genes encoding transcription factors - such as HESX1, SOX2, SOX3, LHX3, LHX4, PROP1, POU1F1, PITX, GLI3, GLI2, OTX2, ARNT2, IGSF1, FGF8, FGFR1, PROKR2, PROK2, CHD7, WDR11, NFKB2, PAX6, TCF7L1, IFT72, GPR161 and CDON - have been associated with pituitary dysfunction and abnormal pituitary gland development; the correlation of genetic mutations to endocrine and MRI phenotypes has improved our knowledge of pituitary development and management of patients with hypopituitarism, both in terms of possible genetic counseling, and of early diagnosis of evolving anterior pituitary hormone deficiencies.

Small metacarpal bones of low quality in obese children

It is still not known whether fat mass excess could exert a positive effect on bone. The aim of our study was to evaluate bone strength and quality in a group of overweight and obese children and adolescents by assessing bone geometry at metacarpal bones and ultrasound at phalangeal level.

Quantitative ultrasound detects bone changes following bone marrow transplantation in pediatric subjects with hematological diseases: A longitudinal study

Background: Bone marrow transplantation (BMT) is associated with bone morbidity. We investigated bone status with quantitative ultrasound (QUS) in pediatric patients with hematological diseases prior to and up to 3 yr following BMT. Methods: Phalangeal QUS measures for amplitude-dependent speed of sound (Ad-SoS) and bone transmission time (BTT) were obtained in 40 hematological patients (25 with malignant, 15 with non-malignant disease; 9.7±4.9 yr) before BMT and 6, 12, 24, and 36 months after BMT. Bone parameters were expressed as Z-scores based on age-sex-matched normal controls. Results: Mean Ad-SoS and BTT Z-scores were normal before BMT and reduced at 36 months (analysis of variance: p=0.0542 and p=0.0233). Ad-SoS and BTT Z-scores remained relatively stable in the first 6 months after BMT and then progressively decreased reaching a plateau at 12–36 months. In non-malignant patients, BTT Z-score decreased at 6–12 months (p=0.029) and subsequently increased, while in malignant patients BTT Z-score showed a decrease at 12–24 months. Pre-pubertal subjects displayed a drop of BTT Z-Score values at both 12 (p=0.023) and 36 months after BMT (p=0.049), while BTT Z-score remained relatively unchanged in pubertal subjects. Early impairment of BTT Z-score was found in patients who suffered acute graft versus host disease (GVHD) compared to patients without this clinical condition; BTT Z-score was lower at 36 months (p=0.045). Conclusions: Longitudinal assessment by QUS of pediatric BMT survivors evidenced that bone status is mildly affected up to 36 months after BMT, mainly in malignant patients, in pre-pubertal subjects at BMT and in patients who suffered acute GVHD.

CNNM2 homozygous mutations cause severe refractory hypomagnesemia, epileptic encephalopathy and brain malformations

Magnesium (Mg2+) plays a crucial role in many biological processes especially in the brain, heart and skeletal muscle. Mg2+ homeostasis is regulated by intestinal absorption and renal reabsorption, involving a combination of different epithelial transport pathways. Mutations in any of these transporters result in hypomagnesemia with variable clinical presentations. Among these, CNNM2 is found along the basolateral membrane of distal tubular segments where it is involved in Mg2+ reabsorption. To date, heterozygous mutations in CNNM2 have been associated with a variable phenotype, ranging from isolated hypomagnesemia to intellectual disability and epilepsy. The only homozygous mutation reported so far, is responsible for hypomagnesemia associated with a severe neurological phenotype characterized by refractory epilepsy, microcephaly, severe global developmental delay and intellectual disability. Here, we report the second homozygous CNNM2 mutation (c.1642G > A,p.Val548Met) in a Moroccan patient, presenting with hypomagnesemia and severe epileptic encephalopathy. Thus, we review and discuss the phenotypic spectrum associated with CNNM2 mutations.

Novel CNS malformations and skeletal anomalies in a patient with Beaulieu-boycott-Innes syndrome

THO/TREX (transcription/export) is a conserved eukaryotic complex that plays a crucial role in gene expression and prevents DNA damage during mitosis and meiosis. In mammals, TREX is essential during embryogenesis, determining stem cell fate specification by regulating posttranscriptional self‐renewal and differentiation in several tissues. It is composed of a core called THO, consisting of THOC1, 2, 5, 6, 7, and additional proteins. Bi‐allelic mutations in THOC6 have been associated to Beaulieu–Boycott–Innes syndrome (BBIS), a syndromic form of intellectual disability (ID). To date, nine patients harbouring homozygous or compound heterozygous mutations in THOC6 have been reported. Despite the clinical heterogenity and subtle dysmorphic features in some individuals, distinctive facial features are tall forehead, short and upslanting palpebral fissures, deep set eyes, flat philtrum, and malocclusion. Nonlife threatening congenital anomalies are common, including cardiac and renal malformations, anteriorly displaced anus, cryptorchidism in males, submucous cleft palate, and corpus callosum dysgenesis. Affected patients usually have short stature, mild microcephaly, and mild to moderate ID. Here, we describe an Italian patient with BBIS, carrying two compound heterozygous loss‐of‐function (LoF) variants in THOC6 (c.577C > T, p.R193* and c.792_793delCA, p.V264Vfs*48). In addition to the common phenotype, she displays cerebellar hypoplasia with severe vermian dysgenesis and hydrocephalus due to aqueductal stenosis, multiple skeletal anomalies and hypergonadotropic hypogonadism. Thus, we review the previous cases and discuss the phenotypic spectrum of BBIS, providing further evidence regarding the pivotal role of TREX complex in human development.

PO2-15: Insulin tolerance test and GHRH plus arginine in the reassessment of pituitary function at adult height achievement

N . Di Iorgi1, M .C . Salerno2, M . Cappa3, S . Loche4, G . Radetti5, D . Capaldo6, A . Allegri7, F . Napoli8, A . Calcagno7, O .B . Iovovich9, S . Noli7, S . Parodi10, M . Maghnie1 . 1DINOGMI, Endocrine Unit, IRCCS G Gaslini, University of Genova, Genova, Italy, 2Traslational Medical Sciences, Pediatric Endocrinology Unit, University Federico II, Naples, Italy, 3Unit of Endocrinology and Diabetology, Bambino Gesu Children’s Hospital, IRCCS, Rome, Italy, 4Pediatric Endocrine Unit, Ospedale Microcitemico, Cagliari, Italy, 5Pediatrics, Regional Hospital, Bolzano, Italy, 6Traslational Medical Sciences, Pediatric Endocrinology Unit, Federico II, Naples, Italy, 7DINOGMI, Endocrine Unit, University of Genova, Genova, Italy, 8Endocrine Unit, IRCCS, G Gaslini, Genova, Italy, 9Divisione di Laboratorio, IRCCS, G Gaslini, Genova, Italy, 10Institute of Electronics, Computer and Telecommunication Engineering, National Research Council of Italy, Genova, Italy