Estimation of the reference values and decision limits for growth hormone in newborns using dried blood spots.

OBJECTIVES: Severe deficiency of growth hormone (GHD) of the newborn is a rare but potentially life-threatening disease. GH measured during the first week of life, using dried blood spots (DBS), may offer several advantages. Aim of the study was to estimate the reference values for GH in newborns by a new analytical method using DBS. METHODS: Using a new developed analytical method, GH was estimated from DBS of 1,036 healthy newborns attending the Neonatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of Milan in the period July-October 2021. Reference values for GH deficiency were estimated by the Harrell-Davis bootstrap method, with 90 %CI calculated by the bias-corrected and accelerated bootstrap method. RESULTS: All GH measurements required 33 analytical sessions (8 months) with a CV% for calibration curve slopes equal to 6.9 %. Intermediate precision evaluated by measurement of low (3 µg/L) and high (10 µg/L) quality controls was, respectively, 14 and 6.5 %. GH reference values, estimated at percentiles 1.0st, 2.5th and 5.0th, and their 90 %CI, were, respectively, 4.5 µg/L (90 %CI 3.8-5.1), 5.9 µg/L (90 %CI 5.4-6.4) and 7.0 µg/L (90 %CI 6.7-7.3). GH levels were not associated with sex, standard deviation scores, birth weight, gestational age, type of delivery or mother's variables (age, smoking habit, gestational diabetes). CONCLUSIONS: Validation data suggest that this method can be used to measured GH in newborns using DBS. The reference values estimated in this study are in accordance with previous published works using ELISA and may help confirming the clinical suspicion of neonatal GHD.

Trabecular Bone Score (TBS) and Bone Metabolism in Patients Affected with Type 1 Neurofibromatosis (NF1).

In patients with neurofibromatosis type 1 (NF1), decreased bone mineral density (BMD) and low levels of 25-hydroxy vitamin D3 (25OHD) have been reported. Recently, the trabecular bone score (TBS) measurement has been proposed as index of bone microarchitecture and fracture risk. In 74 NF1 patients (48 females, 26 males, age 41 ± 12), we measured TBS and investigated clinical stage, lifestyle, vitamin D, serum bone turnover markers, vertebral and femoral BMD. A homogenous cohort of 61 healthy subjects was used as control group. TBS was lower in NF1 patients (1.266 ± 0.113 vs. 1.346 ± 0.105) without differences between sexes. No correlations with 25OHD, low exercise, low calcium intake, reduced sun exposure, and number of skin neurofibromas were observed. As expected, hypovitaminosis D was common (98.6%), as well as BMD reduction in hip and spine sites: In NF1 patients, bone texture evaluated by TBS was low in both sexes without any correlation with clinical or metabolic parameters, suggesting a direct role of the fibromin mutation.

Evaluation of pituitary function after infectious meningitis in childhood.

BACKGROUND: A number of studies of adults have shown that pituitary deficiencies can develop in a considerable proportion of subjects during the acute phase of meningitis or years after the infection has disappeared. The results of the very few studies of the impact of pediatric meningitis on hypothalamic-pituitary function are conflicting. METHODS: In order to determine the incidence of pituitary dysfunction in children with central nervous system infection, we evaluated pituitary function and anthropometric parameters in 19 children with meningitis of different etiologies (15 males; mean age ± standard deviation [SD] at pituitary evaluation, 5.9 ± 4.0 years; mean time from the acute event ± SD, 18 ± 10 months). RESULTS: All of the subjects had a normal stature and growth velocity for their age and gender, and none of them was obese. On the basis of Tanner's reference charts, 17 subjects (13 boys and all four girls) were pre-pubertal; two boys were in Tanner stage 2. None of the subjects had central hypothyroidism. All of the patients had normal serum of insulin growth factor (IGF)-I and prolactin. Their sex steroid and gonadotropin levels were concordant with their age and pubertal status. Early morning urine osmolality and serum electrolyte levels showed no signs of diabetes insipidus. All of the patients had normal plasma adrenocorticotropic hormone (ACTH) levels. Peak cortisol responses to the standard dose Synacthen test (SDST) were normal in all cases. CONCLUSIONS: The results showed that hypopituitarism following infectious meningitis appears to be infrequent in childhood and children's pituitary glands seem to be less vulnerable to damage than those of adults.

Short stature in PRMT7 Mutations: first evidence of response to growth hormone treatment.

Protein arginine methyltransferase 7 (PRMT7) pathogenetic variants have been associated with the human disorder of Short Stature, Brachydactyly, Intellectual Developmental Disability and Seizures syndrome (SBIDDS). Only 15 cases have been described in the literature. Here we report two female dizygotic twins with novel compound heterozygous deleterious variants of PRMT7 and describe the associated endocrine manifestations and short-term response to recombinant growth hormone (rGH) treatment. They were born at 36 + 3 weeks from a dichorionic diamniotic twin pregnancy. Twin A was appropriate for gestational age while Twin B was small for gestational age. Whole exome sequencing analyses showed the same novel compound heterozygous genetic defects in the PRMT7 gene (c.1220 G > A of maternal origin; c.1323 + 2 T > G of paternal origin, Fig. 1). Due to severe short stature and growth impairment, at six years of age, endocrine investigations were performed to rule out growth hormone (GH) deficiency, and revealed GH deficiency (GHD) in Twin A and an appropriate GH response in Twin B. Therefore, both started rGH, albeit at different dosages according to the underlying diagnosis. Both showed a satisfactory short-term response to treatment with height gain (∆HT) of +0.52 SDS (Twin A) and +0.88 SDS (Twin B) during the first year. In conclusion, our findings expand the knowledge about the endocrine manifestations associated with PRMT7 pathogenetic variants, including GH deficiency and rGH response. Further studies are needed to investigate long-term outcomes and establish whether PRMT7 genetic defects can be included among syndromic short stature treatable with rGH.

Towards an individualized management of pubertal induction in girls with hypogonadism: insight into the best replacement outcomes from a large multicentre registry.

OBJECTIVE: An evidence-based pubertal induction scheme in hypogonadal girls is still to be established. Interestingly, literature data report a suboptimal uterine longitudinal diameter (ULD) in >50% of treated hypogonadal women, negatively influencing their pregnancy outcomes. This study aims to investigate auxological and uterine outcomes of pubertal induction in girls in the light of underlying diagnosis and therapeutic schemes used. DESIGN: Retrospective analysis of longitudinal data from a multicentric registry. METHODS: Auxological, biochemical, and radiological data were collected at baseline and during follow-up in 95 hypogonadal girls (chronological age > 10.9 years, Tanner stage ≤ 2) treated with transdermal 17ß-oestradiol patches for at least 1 year. Induction was started at a median dose of 0.14 mcg/kg/day with a 6-monthly increase and was considered completed for 49/95 patients who started progesterone with a concomitant oestrogen adult dose. RESULTS: At the end of induction, the achievement of the complete breast maturation was associated with a 17ß-oestradiol dose at progesterone introduction. ULD showed a significant correlation with a 17ß-oestradiol dosage. Final ULD was >65 mm in only 17/45 girls. At multiple regression analysis, pelvic irradiation represented the major determinant of reduced final ULD. After correction for uterine irradiation, ULD was associated with the 17ß-oestradiol dose at progesterone introduction. Final ULD was not significantly different from the one assessed after progesterone introduction. CONCLUSIONS: Our results provide evidence that progestins, hampering further changes in uterine volume and breast development, should be introduced only in the presence of a concomitant adequate 17ß-oestradiol dose and an appropriate clinical response.

A single-centre study on predictors and determinants of pubertal delay and growth impairment in Epidermolysis Bullosa.

BACKGROUND: Delayed puberty is a possible complication of Epidermolysis Bullosa (EB), though the actual incidence is still unknown. In chronic illnesses delayed puberty should be correctly managed since, if untreated, can have detrimental effects on adult height attainment, peak bone mass achievement and psychological health. AIMS AND METHODS: This is a single-centre study on pubertal development, growth and bone status in EB. Auxological, densitometric (areal Bone Mineral Density-aBMD Z-score, Bone Mineral Apparent Density-BMAD Z-score, Trabecular Bone Score-TBS and Bone Strain Index-BSI at Lumbar spine) and body composition data (Total Body DXA scans) were collected. Disease severity was defined according to Birmingham Epidermolysis Bullosa Severity (BEBS) score. RESULTS: Twenty-one patients (12 Recessive Dystrophic EB-RDEB, 3 Dominant Dystrophic EB, 3 Junctional EB-JEB, 2 EB Simplex and one Kindler EB) aged 13 years (females) or 14 years (males) and above were enrolled (age 16.2±2.5 years, M/F 11/10). Short stature was highly prevalent (57%, mean height -2.12±2.05 SDS) with 55% patients with height <-2SD their mid-parental height. 7/21 patients (33%, 6 RDEB and 1 JEB) had delayed puberty with a median BEBS of 50 (range 29 to 63), a height SDS of -2.59 SDS (range -5.95 to -2.22) and a median lumbar BMAD Z-score of -4.0 SDS (range -5.42 to -0.63 SDS). Pubertal status was negatively associated with BEBS, skin involvement, inflammatory state and positively with height SDS and BMI SDS. CONCLUSIONS: Pubertal delay is highly prevalent in EB, especially in patients with RDEB and JEB, high severity score and inflammatory state. Moreover, pubertal delay worsens growth impairment and bone health. A study on pubertal induction is ongoing to enlighten possible beneficial effects on adult height attainment and peak bone mass accrual.

Effect of Vitamin D and Docosahexaenoic Acid Co-Supplementation on Vitamin D Status, Body Composition, and Metabolic Markers in Obese Children: A Randomized, Double Blind, Controlled Study.

Obese children are at high risk of developing vitamin D deficiency. Omega-3 polyunsaturated fatty acids and their derivatives might have a beneficial effect on vitamin D status of obese children, due to their anti-inflammatory action, and increasing its absorption. This multicenter, randomized, double-blind controlled study aims to investigate the effect of vitamin D and docosahexaenoic acid (DHA) co-supplementation for six months on vitamin D status, body composition, and metabolic markers of obese children with vitamin D deficiency. A total of 108 children were enrolled and 73 children completed the study: 33 were supplemented with an oral dose of 500 mg of DHA and 1200 IU/day of vitamin D3 and 41 were supplemented with 1200 IU/day of vitamin D3 + wheat germ oil. At the end of the study, more than 50% of the subjects improved their vitamin D status. However, co-supplementation was not more effective than vitamin D plus wheat germ oil. Fat mass percentage was significantly reduced, and body mass index improved in both groups, even if all the subjects were still obese at the end of the study. Children receiving both vitamin D and DHA presented a higher increase of DHA levels that could be relevant to prevent inflammatory-associated complications of obesity, but they had no effect on vitamin D levels.

GH Deficiency and Replacement Therapy in Hypopituitarism: Insight Into the Relationships With Other Hypothalamic-Pituitary Axes.

GH deficiency (GHD) in adult patients is a complex condition, mainly due to organic lesion of hypothalamic-pituitary region and often associated with multiple pituitary hormone deficiencies (MPHD). The relationships between the GH/IGF-I system and other hypothalamic-pituitary axes are complicated and not yet fully clarified. Many reports have shown a bidirectional interplay both at a central and at a peripheral level. Signs and symptoms of other pituitary deficiencies often overlap and confuse with those due to GH deficiency. Furthermore, a condition of untreated GHD may mask concomitant pituitary deficiencies, mainly central hypothyroidism and hypoadrenalism. In this setting, the diagnosis could be delayed and possible only after recombinant human Growth Hormone (rhGH) replacement. Since inappropriate replacement of other pituitary hormones may exacerbate many manifestations of GHD, a correct diagnosis is crucial. This paper will focus on the main studies aimed to clarify the effects of GHD and rhGH replacement on other pituitary axes. Elucidating the possible contexts in which GHD may develop and examining the proposed mechanisms at the basis of interactions between the GH/IGF-I system and other axes, we will focus on the importance of a correct diagnosis to avoid possible pitfalls.

Influence of biochemical diagnosis of growth hormone deficiency on replacement therapy response and retesting results at adult height.

Isolated growth hormone deficiency (IGHD) is the most frequent endocrinological disorder in children with short stature, however the diagnosis is still controversial due to the scarcity of reliable diagnostic criteria and pre-treatment predictive factors of long term-response. To evaluate recombinant growth hormone (rGH) long-term response and retesting results in three different groups of children divided in accordance with the biochemical criteria of initial diagnosis. Height gain (∆HT) at adult height (AH) and retesting results were evaluated in 57 rGH treated children (M = 34, 59.6%) divided into 3 groups according to initial diagnosis: Group A (n = 25) with max GH peak at stimulation test < 8 µg/L, Group B (n = 19) between 8 and 10 µg/L and Group C (n = 13) with mean overnight GH < 3 µg/L (neurosecretory dysfunction, NSD). Retesting was carried out in all patients after at least one month off therapy upon reaching the AH. 40/57 (70.2%) patients were pre-pubertal at diagnosis and showed ∆HT of 1.37 ± 1.00 SDS, with no significant differences between groups (P = 0.08). Nonetheless, 46% patients in Group B showed ∆HT < 1SDS (vs 13% and 12% in Group A and C, respectively) and 25% children failed to reach mid-parental height (vs 6% and 0% in Group A and C, respectively). At AH attainment, IGHD was reconfirmed in 28% (7/25) and 10% (2/19) in Group A and B, respectively. A reduction of diagnostic cut-off at GH stimulation tests could better discriminate between "good" and "poor responders" and predict the persistence of IGHD through transition. Group C response and the predictive value of baseline IGF-I SDS bring back to light NSD: should we consider an underlying hypothalamic derangement when the clinical presentation is strongly consistent with IGHD but pharmacological stimulation test is normal?

Adrenal Insufficiency at the Time of COVID-19: A Retrospective Study in Patients Referring to a Tertiary Center.

CONTEXT: Coronavirus disease 2019 (COVID-19) represents a global health emergency, and infected patients with chronic diseases often present with a severe impairment. Adrenal insufficiency (AI) is supposed to be associated with an increased infection risk, which could trigger an adrenal crisis. OBJECTIVE: Our primary aim was to evaluate the incidence of COVID-19 symptoms and complications in AI patients. DESIGN AND SETTING: We conducted a retrospective case-control study. All patients were on active follow-up and lived in Lombardy, Italy, one of the most affected areas. PATIENTS: We enrolled 279 patients with primary and secondary AI and 112 controls (patients with benign pituitary lesions without hormonal alterations). All AI patients had been previously trained to modify their replacement therapy on stress doses. INTERVENTION: By administering a standardized questionnaire by phone, we collected data on COVID-19 suggestive symptoms and consequences. RESULTS: In February through April 2020, the prevalence of symptomatic patients (complaining at least 1 symptom of viral infection) was similar between the 2 groups (24% in AI and 22.3% in controls, P = 0.79). Highly suggestive COVID-19 symptoms (at least 2 including fever and/or cough) also occurred equally in AI and controls (12.5% in both groups). No patient required hospitalization and no adrenal crisis was reported. Few nasopharyngeal swabs were performed (n = 12), as indicated by sanitary regulations, limiting conclusions on the exact infection rate (2 positive results in AI and none in controls, P = 0.52). CONCLUSIONS: AI patients who are adequately treated and trained seem to display the same incidence of COVID-19-suggestive symptoms and disease severity as controls.

Adrenal Insufficiency at the Time of COVID-19: A Retrospective Study in Patients Referring to a Tertiary Center.

CONTEXT: Coronavirus disease 2019 (COVID-19) represents a global health emergency, and infected patients with chronic diseases often present with a severe impairment. Adrenal insufficiency (AI) is supposed to be associated with an increased infection risk, which could trigger an adrenal crisis. OBJECTIVE: Our primary aim was to evaluate the incidence of COVID-19 symptoms and complications in AI patients. DESIGN AND SETTING: We conducted a retrospective case-control study. All patients were on active follow-up and lived in Lombardy, Italy, one of the most affected areas. PATIENTS: We enrolled 279 patients with primary and secondary AI and 112 controls (patients with benign pituitary lesions without hormonal alterations). All AI patients had been previously trained to modify their replacement therapy on stress doses. INTERVENTION: By administering a standardized questionnaire by phone, we collected data on COVID-19 suggestive symptoms and consequences. RESULTS: In February through April 2020, the prevalence of symptomatic patients (complaining at least 1 symptom of viral infection) was similar between the 2 groups (24% in AI and 22.3% in controls, P = 0.79). Highly suggestive COVID-19 symptoms (at least 2 including fever and/or cough) also occurred equally in AI and controls (12.5% in both groups). No patient required hospitalization and no adrenal crisis was reported. Few nasopharyngeal swabs were performed (n = 12), as indicated by sanitary regulations, limiting conclusions on the exact infection rate (2 positive results in AI and none in controls, P = 0.52). CONCLUSIONS: AI patients who are adequately treated and trained seem to display the same incidence of COVID-19-suggestive symptoms and disease severity as controls.

A case of testicular atrophy associated with cystic fibrosis.

SUMMARY: An 8-year-old boy with cystic fibrosis came to our attention for an empty scrotum. General physical examination showed a normal penis and hypoplastic scrotum with non-palpable testes bilaterally. Routine blood investigations showed low levels of LH, testosterone, inhibin B and antiMullerian hormone and elevated levels of FSH. Karyotype was normal. An abdominal ultrasound confirmed the absence of the testes into the scrotum, in the inguinal region and abdomen. At laparoscopy were noted bilaterally hypotrophic spermatic vessels, absence of the vas deferens and a closed inner ring. Inguinal exploration found out a small residual testis and histological examination showed fibrotic tissue. This is the first case of testicular atrophy associated to CFTR mutation described. The process that led to bilateral testicular and vas deferens atrophy remains unexplained, a possible influence of CFTR dysfunction cannot be ruled out, although it is possible that these conditions are independently associated. LEARNING POINTS: Cystic fibrosis produces a multisystemic disease which can affect also the reproductive tract. Nearly 97-98% of male patients are infertile because of congenital bilateral absence of vas deferens. A correlation between cystic fibrosis and bilateral testicular atrophy could be possible.

A nutrition-based approach to epidermolysis bullosa: Causes, assessments, requirements and management.

Inherited epidermolysis bullosa (EB) is a clinically and genetically heterogeneous group of rare diseases characterized by skin and mucous membrane fragility. EB primarily involves the skin and, in specific subtypes, the mucous membrane, resulting in complications which can strongly affect nutritional status (e.g. gastrointestinal complications, hand deformities, pain). The aims of nutritional support mainly include improving nutritional status, alleviating the stress of oral feeding and minimizing nutritional deficiencies, thus consequently improving growth, pubertal development, bowel function, immune status and wound healing. The aim of this review is to discuss knowledge of different aspects of the disease related to nutrition and growth.

Case Report: Late-Onset Congenital Adrenal Hyperplasia and Acute Covid-19 Infection in a Pregnant Woman: Multidisciplinary Management.

Background: The impact of the Covid-19 infection on patients with chronic endocrine disease is not fully known. We describe here the first case of a pregnant woman with Covid-19 acute infection and non-classical congenital adrenal hyperplasia (NCAH). Case description: A woman at 36 weeks of gestation was referred to our Maternity Hospital for premature rupture of membranes (PROM). Her medical history was positive for NCAH on chronic steroid replacement till the age of 17 years (cortisone acetate and dexamethasone, both in the morning). At admission, her naso-oro-pharyngeal swab resulted positive for SARS-CoV-2. Due to hyperpyrexia and late preterm PROM, cesarean section was planned, and she was started on a 100 mg-bolus of hydrocortisone, followed by continuous infusion of 200 mg/24 h. A female neonate in good clinical condition and with a negative nasopharyngeal Covid-19 swab was delivered. On second postpartum day, the mother was in good condition and was switched to oral steroid therapy. On third postpartum day she worsened, with radiological signs of acute pulmonary embolism. Oro-tracheal intubation and mechanical ventilation were started, and she was switched back to intravenous steroid therapy. On April 30, pulmonary embolism was resolved, and on May 13th she was discharged in good condition. Conclusions: We report the first case of Covid-19 acute infection that occurred in late-pregnancy in a woman with NCAH on chronic steroid replacement. The management of the patient in a reference center with early involvement of a multidisciplinary team granted prompt care and adequate protection for all the involved sanitary operators.

Pediatric dual-energy X-ray absorptiometry in clinical practice: What the clinicians need to know.

The importance of childhood and adolescence for bone development and mineral accrual is increasingly accepted, leading to a need of suitable methods for monitoring bone health even in pediatric setting. Among the several different imaging methods available for clinical measurement of bone mineral density (BMD) in children, dual-energy X-ray absorptiometry (DXA) is the most widely available and commonly used due to its reproducibility, negligible radiation dose and reliable pediatric reference data. Nevertheless, DXA in children has some technical specific features that should be known by those physicians who interpret and report this examination. We provide recommendations for optimal DXA scan reporting in pediatric setting, including indications, skeletal sites to be examined, parameters to be measured, timing of follow-up BMD measurements. Adequate report and analysis of DXA examinations are essential to prevent over- and underdiagnosis of bone mineral impairment in pediatric patients. In conclusion, a complete and exhaustive DXA report in children and adolescents is mandatory for an accurate diagnosis and a precise monitoring of pediatric bone status.

Progressive bone impairment with age and pubertal development in neurofibromatosis type I.

Bone density impairment represents an established complication in adults with neurofibromatosis type 1, while few data exist in the pediatric population. Age- and gender-adjusted bone mass decreases with age and pubertal development, identifying childhood as the best time frame to introduce prevention strategies aiming at peak bone mass achievement. PURPOSE: The present study aims at evaluating bone mineral density (BMD) in a population of children with neurofibromatosis type I (NF-1), with particular focus on changes occurring during growth and pubertal development. METHODS: Bone metabolic markers and bone status [by dual-energy X-ray absorptiometry scans (DXA) of the total body and lumbar spine with morphometric analysis] were assessed in 50 children (33 males; mean age ± SD, 11.6 ± 4 years). Bone mineral apparent density (BMAD), trabecular bone score (TBS), and bone strain (BS) of the lumbar spine (LS) DXA were also obtained. RESULTS: In our cohort areal BMD (aBMD) Z-score was below the mean in 88% of the patients at LS (70% after correction for bone size) and in 86% considering total body (TB) DXA. However, aBMD Z-score was < - 2 in 12% after correction for bone size at LS and TB, respectively. Lumbar spine aBMD Z-score (r = - 0.54, P < 0.0001), LS BMAD Z-score (r = - 0.53, P < 0.0001), and TB Z-score (r = - 0.39, P = 0.005) showed a negative correlation with growth and pubertal development (P = 0.007, P = 0.02, P = 0.01, respectively), suggesting that patients failed to gain as much as expected for age. CONCLUSION: Bone density impairment becomes more evident with growth and pubertal development in NF-1 patients, thus identifying childhood as the best time frame to introduce prevention strategies aiming at peak bone mass achievement. TBS and BS, providing bone DXA qualitative information, could be useful during longitudinal follow-up for better characterizing bone impairment in these patients.

Central hypothyroidism - a neglected thyroid disorder.

Central hypothyroidism is a rare and heterogeneous disorder that is characterized by a defect in thyroid hormone secretion in an otherwise normal thyroid gland due to insufficient stimulation by TSH. The disease results from the abnormal function of the pituitary gland, the hypothalamus, or both. Moreover, central hypothyroidism can be isolated or combined with other pituitary hormone deficiencies, which are mostly acquired and are rarely congenital. The clinical manifestations of central hypothyroidism are usually milder than those observed in primary hypothyroidism. Obtaining a positive diagnosis for central hypothyroidism can be difficult from both a clinical and a biochemical perspective. The diagnosis of central hypothyroidism is based on low circulating levels of free T4 in the presence of low to normal TSH concentrations. The correct diagnosis of both acquired (also termed sporadic) and congenital (also termed genetic) central hypothyroidism can be hindered by methodological interference in free T4 or TSH measurements; routine utilization of total T4 or T3 measurements; concurrent systemic illness that is characterized by low levels of free T4 and normal TSH concentrations; the use of the sole TSH-reflex strategy, which is the measurement of the sole level of TSH, without free T4, if levels of TSH are in the normal range; and the diagnosis of congenital hypothyroidism based on TSH analysis without the concomitant measurement of serum levels of T4. In this Review, we discuss current knowledge of the causes of central hypothyroidism, emphasizing possible pitfalls in the diagnosis and treatment of this disorder.

Focus on GH deficiency and thyroid function.

The relationships between GH system and hypothalamic-pituitary-thyroid axis are complex and not yet fully understood. The reported effects of GH administration on thyroid status of GHD patients have been remarkably divergent. This review will focus on the main studies aimed to clarify the effects of GH on thyroid function, firstly going through the diagnosis of central hypothyroidism and its possible pitfalls, then elucidating the possible contexts in which GHD may develop and examining the proposed mechanisms at the basis of interactions between the GH-IGF-I system and the hypothalamic-pituitary-thyroid axis.