Intact FGF23 concentration in healthy infants, children, and adolescents, and diagnostic usefulness in patients with X-linked hypophosphatemic rickets.

OBJECTIVE: FGF23 measurement may have a diagnostic role to investigate patients with phosphate disorders. However, normal values for infants, children, and adolescents have not been defined. METHODS: In a total of 282 (males 145, females 137) healthy infants (n = 30), prepubertal (n = 147), pubertal (n = 59), and postpubertal (n = 46), and in twenty patients with X-linked hypophosphatemic rickets (XLH, age 10.2 ± 5.6 years) serum phosphate (automated analyzer), and plasma intact FGF23 (immunochemiluminescent sandwich assay, DiaSorin) concentrations were measured. RESULTS: Intact FGF23 concentrations were higher in healthy infants than in prepubertal (P < 0.01) and postpubertal subjects (P < 0.05); pubertal subjects showed higher values (P < 0.05) than postpubertal subjects. Serum phosphate concentrations were higher (P < 0.001) in healthy infants than in prepubertal, pubertal, and postpubertal subjects. Pubertal subjects had higher (P < 0.001) serum phosphate concentrations than postpubertal subjects. Intact FGF23 and serum phosphate concentrations did not differ (P = NS) by sex, age of menarche, and time after menarche. In healthy subjects, there was no correlation between intact FGF23 and serum phosphate concentrations. Intact FGF23 concentrations were higher (P < 0.0001) in patients with XLH than in healthy subjects according to chronological age and pubertal development. In all patients, intact FGF23 concentrations were above 40 pg/mL; intact FGF23 concentrations were inversely correlated with serum phosphate concentrations (r = -0.65; P < 0.01). CONCLUSION: In healthy subjects, chronological age and puberty were main determinants of intact FGF23 concentrations. Intact FGF23 concentrations may be a useful marker for the early diagnosis of XLH in pediatric patients.

The diagnosis of hypophosphatasia in children as a multidisciplinary effort: an expert opinion.

Hypophosphatasia (HPP) is a rare genetic disorder in which pathogenic variants of the ALPL gene lead to a marked decrease of tissue non-specific alkaline phosphatase (TNSALP) activity. Although HPP is a systemic disorder, its clinical manifestations are more evident on bones, teeth, muscle and central nervous system. The clinical spectrum ranges from severe forms with extreme skeletal deformities, respiratory impairment, seizures, to very mild forms with onset in late adulthood and few clinical signs. The diagnosis can be suspected by measurement of TNSALP activity, but the insufficient awareness among health professionals and the lack of official guidelines are responsible for delayed diagnosis in children with HPP. The purpose of the current document is to provide an expert opinion directed at optimizing the diagnostic pathway of pediatric HPP. From April to December 2022, a multidisciplinary working group of 6 experts including two pediatric endocrinologists, a pediatric neurologist, a pediatric odontologist, a clinical geneticist, and a molecular biologist gathered in a series of periodic meetings to discuss the main issues related to the diagnosis of HPP in children and formalize an Expert Opinion statement. The experts agreed on a diagnostic trail that begins with the recognition of specific clinical signs, leading to biochemical analyses of TNSALP activity and vitamin B6 serum concentration. Very important are the neurological and dental manifestation of the disease that should be thoroughly investigated. The evaluation of TNSALP activity must consider sex and age variability and low activity must be persistent. Repeated blood measurements are thus necessary. The molecular analysis is then mandatory to confirm the diagnosis and for genetic counseling.

Providing high-quality care remotely to patients with rare bone diseases during COVID-19 pandemic.

During the COVID-19 outbreak, the European Reference Network on Rare Bone Diseases (ERN BOND) coordination team and Italian rare bone diseases healthcare professionals created the "COVID-19 Helpline for Rare Bone Diseases" in an attempt to provide high-quality information and expertise on rare bone diseases remotely to patients and healthcare professionals. The present position statement describes the key characteristics of the Helpline initiative, along with the main aspects and topics that recurrently emerged as central for rare bone diseases patients and professionals. The main topics highlighted are general recommendations, pulmonary complications, drug treatment, trauma, pregnancy, children and elderly people, and patient associations role. The successful experience of the "COVID-19 Helpline for Rare Bone Diseases" launched in Italy could serve as a primer of gold-standard remote care for rare bone diseases for the other European countries and globally. Furthermore, similar COVID-19 helplines could be considered and applied for other rare diseases in order to implement remote patients' care.

17ß-hydroxysteroid dehydrogenase type 3 deficiency: female sex assignment and follow-up.

BACKGROUND: Deficiency of 17ß-hydroxysteroid dehydrogenase type 3 (17ß-HSD3) is a rare autosomal recessive 46,XY disorder of sex development (DSD). It is due to pathogenetic variants in the HSD17B3 gene. Mutated genes encode an abnormal enzyme with absent or reduced ability to convert Δ4-androstenedione (Δ4-A) to testosterone (T) in the fetal testis. Affected individuals are usually raised as females and diagnosis is made at puberty, when they show virilization. METHODS: A girl with a presumptive diagnosis of complete androgen insensitivity syndrome underwent endocrine and genetic assessment. Long-term follow-up was reported. RESULTS: The diagnosis of 17ß-HSD3 deficiency was made (stimulated T/Δ4-A ratio: 0.15; HSD17B3 gene analysis: c.277+4A>T in intron 3/c.640_645del (p.Glu214_Glu215del) in exon 9. After extensive information, parents decided to maintain female sex. Gonadal removal was performed and histological evaluation demonstrated deep fibrosis of testicular tissue. Follow-up till 8.5 years of age showed somatic and neuro-psychological development fitting with the female sex. CONCLUSIONS: Management of a child with the rare 17ß-HSD3 deficiency remains challenging. Any decision must be carefully evaluated with parents. Long-term follow-up must be warranted by a multidisciplinary DSD team to evaluate the adequacy of the choices made on quality of life in later life.

Vitamin D status and the immune assessment in 22q11.2 deletion syndrome.

22q11.2 deletion syndrome (22q11.2DS) is characterized by a heterogeneous phenotype, including alterations in phospho-calcium metabolism and immunodeficiency. We analyzed vitamin D status and the immune assessment, focusing on T cell subpopulations and dendritic cells (DCs) in a cohort of 17 pediatric 22q11.2DS patients and 17 age-matched healthy subjects. As antigen-presenting cells, DCs are the main target of vitamin D, promoting a tolerogenic T cell response. Patients were subdivided into three groups according to the parameters of phospho-calcium metabolism and serum levels of 25OHD: normal values, vitamin D deficiency and hypoparathyroidism. Different degrees of T cell deficiency, ranging from normal to partial T cell numbers, were observed in the cohort of patients. The group with vitamin D deficiency showed a significant reduction of naive T cells and a significant increase of central memory T cells compared to controls. In this group the number of circulating DCs was significantly reduced. DC decrease affected both myeloid and plasmacytoid DC subsets (mDCs and pDCs), with the most relevant reduction involving pDCs. A direct correlation between 25OHD levels and recent thymic emigrant (RTE) and DC number was identified. Despite the limited cohort analyzed, our results show that deficiency of the pDC subset in patients with 22q11.2DS may be included among the causative factors of the progressive increase of risk of autoimmune diseases in these patients. As most patients suffer from increased susceptibility to infections and heightened prevalence of autoimmune disorders, we suggest a potential role of vitamin D supplementation in preventing autoimmune or proinflammatory diseases in 22q11.2DS.

X-linked hypophosphatemic rickets: an Italian experts' opinion survey.

BACKGROUND: X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases. OBJECTIVE: Due to the low prevalence of XLH, an experts' opinion survey was conducted across Italian centers to collect data on XLH and on its management. METHODS: A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy. RESULTS: Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5 years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients. CONCLUSIONS: XLH remains a severe condition with significant morbidities.

Genetic and epigenetic alterations in the GNAS locus and clinical consequences in Pseudohypoparathyroidism: Italian common healthcare pathways adoption.

BACKGROUND: Genetic and epigenetic alterations in the GNAS locus are responsible for the Gsα protein dysfunctions causing Pseudohypoparathyroidism (PHP) type Ia/c and Ib, respectively. For these heterogeneous diseases characterized by multiple hormone resistances and Albright's Hereditary Osteodystrophy (AHO) the current classification results inadequate because of the clinical overlap between molecular subtypes and a standard clinical approach is still missing. In the present paper several members of the Study Group Endocrine diseases due to altered function of Gsα protein of the Italian Society of Pediatric Endocrinology and Diabetology (ISPED) have reviewed and updated the clinical-molecular data of the largest case series of (epi)/genetically characterized AHO/PHP patients; they then produced a common healthcare pathway for patients with these disorders. METHODS: The molecular analysis of the GNAS gene and locus identified the causal alteration in 74 subjects (46 genetic and 28 epigenetic mutations). The clinical data at the diagnosis and their evolution during up to 15 years follow-up were collected using two different cards. RESULTS: In patients with genetic mutations the growth impairment worsen during the time, while obesity prevalence decreases; subcutaneous ossifications seem specific for this group. Brachydactyly has been detected in half of the subjects with epigenetic alterations, in which the disease overts later in life, often with symptomatic hypocalcaemia, and also early TSH and GHRH resistances have been recorded. CONCLUSIONS: A dedicated healthcare pathway addressing all these aspects in a systematic way would improve the clinical management, allowing an earlier recognition of some PHP features, the optimization of their medical treatment and a better clinical-oriented molecular analysis. Furthermore, standardized follow-up data would provide new insight into less known aspects.

45,X maleness: clinical and cytogenetic features in two patients.

45,X maleness is a very rare disorder. We report on 2 new 45,X males aged 9 10/12 and 39 years, respectively. The boy presented for developmental delay, while the man was referred to us because of infertility. Both patients showed short stature (boy -2.29 SDS, man -4.05 SDS) and an unbalanced translocation of Yp, including SRY, onto the long arm of chromosome 10 and short arm of chromosome 14, respectively. The growth pattern of the 2 patients and literature data suggest the presence of a specific growth gene in the pericentrometric region of Yq. In addition, developmental delay in some 45,X males may be related to specific deletion of telomeric autosome regions, but involvement of gene(s) on the Y chromosome may play a role as well. Albeit in the boy inhibin B levels were in the normal range for age, azoospermia was demonstrated in the adult, supporting that infertility is a feature of adult 45,X men with AZFa-c deletion.

Bone health in disorders of sex differentiation.

Sex steroids are main regulators of skeletal growth, maturation and mass in both men and women. People with disorders of sex development (DSD) may experience problems in developing normal bone growth, structure and mass, because abnormal sex steroid secretion or action may be operative. In complete androgen insensitivity syndrome several reports documented reduced bone mineral density (BMD). Reduced BMD is evident in patients with not removed or removed gonads, but it is poorer in the latter, mainly when compliance with estrogen replacement therapy is not guaranteed. Large impairment of BMD does not seem to be present in patients with partial androgen insensitivity syndrome or 5alpha-reductase-2 deficiency, providing that gonads are not removed or that substitutive therapy is optimized. In congenital adrenal hyperplasia, BMD may be impaired as a result of not optimal glucocorticoid administration. In Turner syndrome, impaired BMD may result from the combined actions of estrogen deficiency, low bone dimensions, altered bone geometry, deficient cortical bone, and trabecular bone loss. Optimal estrogen administration seems to be important in preserving bone mass and enhancing trabecular bone volume. On the whole, bone health represents a main clinical issue for the management of persons with disorders of sex differentiation, and well designed longitudinal studies should be developed to improve their bone health and well-being.

A girl with tomboy behavior: lesson from misdiagnosis in a baby with ambiguous genitalia.

5alpha-Reductase-2 deficiency is a rare 46,XY disorder of sex differentiation caused by mutations in the 5alpha-reductase type 2 gene. It presents at birth with variable degree of undervirilization. Here, a baby with 5alpha-reductase-2 deficiency and misdiagnosis of complete androgen insensitivity syndrome, female sex assignment and early gonadectomy is described. During primary school, the girl developed tomboy behavior. Molecular analysis demonstrated compound heterozygosity for 5alpha-reductase type 2 gene mutations (exon 2: Q126R; exon 4: H230P). This child underlines the need for adequate endocrine and genetic testing for a definite diagnosis before gender is assigned in children with ambiguous genitalia and surgical interventions are carried out. Inadequate work-up may result in inappropriate gender assignment in infancy with possible inferences on outcome.

Body composition and metabolic profile in women with complete androgen insensitivity syndrome.

Clinical and experimental data suggest that androgen receptor (AR) signaling plays a role on body composition, glucose homeostasis and lipid metabolism. The effect of AR disruption on such parameters was not extensively investigated in human people. A group of young to middle-age adult women with complete androgen insensitivity syndrome (CAIS, n = 18, age 32.2 +/- 9.3 years; women with testes removed n = 14) was investigated for body mass index (BMI), body composition (dual energy X-ray absorptiometry), serum glucose levels, insulin sensitivity (HOMA-IR) and lipid profile. Mean BMI (24.2 +/- 7.4 kg/m(2)) was not significantly increased (T-score 1.0 +/- 2.5, p = NS vs Italian female reference values), but prevalence of obesity was higher in women with CAIS than that reported in age-related Italian females (16.7% vs 3.6%, respectively). The majority of obese individuals with CAIS was in the subgroup with intact testes (3/4). DXA assessment (n = 15) demonstrated values of total free fat mass similar to that of 46,XX female controls. Increased body fat was found in CAIS women in comparison with both female and male controls. Abnormal values of cholesterol (total and LDL) and HOMA-IR were present in a large subset of patients. Our data suggest that in women with CAIS disruption of AR signaling may increase body fat and affect some metabolic parameters. Assessment of body composition, metabolic profile and, likely, cardiovascular risk seems to be advisable with ageing in these individuals.

17beta-Hydroxysteroid dehydrogenase-3 deficiency: from pregnancy to adolescence.

OBJECTIVE: Aim of this study is to report on basal clinical phenotype and follow up after diagnosis, of patients with 17beta-hydroxysteroid-dehydrogenase type 3 (17beta-HSD3) deficiency in Italy. SETTING: Pediatric Endocrine Departments, University Hospitals. PATIENTS: The cases of 5 Italian subjects affected by 17beta-HSD3 deficiency are presented in this study. INTERVENTIONS: Laboratory and genetic assessment. Gonadectomy and female sex assignment (4 patients) or GnRH analog therapy to regress puberty and gender identity disorder (1 patient). RESULTS: Presentation lasted from pregnancy (pre-natal diagnosis of a 46,XY fetus with female external genitalia) to infancy (inguinal hernia containing testes/clitoromegaly) and adolescence (virilisation). All subjects but one (subject 1, Central-Northern Italy) were from small areas of Southern Italy. Endocrine data (baseline and/or stimulated testosterone/ Delta4-androstenedione ratio) were informative. Two girls were homozygous for 17beta-HSD3 gene mutations (G289S/G289S; R80W/R80W), while the others were compound heterozygous (IVS325+4 A>T/A203V; L212Q/M235V; R80W/A235E). Four patients were confirmed as females and were well-adjusted with assigned sex; gender identity disorder improved during treatment with GnRH analog in the last subject. CONCLUSIONS: 17betaHSD3 deficiency may present from pregnancy to puberty for different clinical issues. Albeit testosterone/Delta4-androstenedione ratio represents the most accurate endocrine marker to diagnose the disorder, hCGstimulation is mandatory in pre-puberty. Molecular analysis of 17beta-HSD3 gene should be performed to confirm the diagnosis. Temporary GnRH analog treatment may regress gender identity disorder and provide time to confirm or change the birth sex assignment. Female individuals seems to be compliant with their sex, providing that virilisation does not occur. In Italy, the disorder seems to be more prevalent in the Southern regions and shows genetic heterogeneity.

Prevalence and pathogenesis of dental and periodontal lesions in children with X-linked hypophosphatemic rickets.

AIM: To assess the prevalence and to investigate the pathogenetic mechanisms of dental and periodontal lesions in children with X-linked hypophosphatemic rickets (XLH) examined at diagnosis or during treatment. METHODS: Nine children with XLH (age 7.2 +/- 3.3 years) were enrolled in the study (at diagnosis, n = 2; during treatment with oral inorganic phosphate salts combined with 1,25-dihydroxyvitamin D3, n = 7). Oral examination was performed according to the evidence of carious and gingival lesions. Decayed or filled teeth (dft) index for primary teeth, and the decayed, missing, or filled teeth (DMFT) index for permanent teeth was assessed. All patients with a history of spontaneous dental abscesses underwent orthopantomography examination. RESULTS: d/D ranged from 0 to 9 and f/F from 0 to 3. DMFT/dft index was 0 in the three youngest patients. One patient had enamel hypoplasia and two had enamel dyschromic alterations. Six out of nine patients (67%) had a history of spontaneous fistulae as a consequence of periapical abscesses occurring in the absence of dental decay or history of injury. In these patients, orthopantomographies showed enlarged pulp chambers associated with prominent pulp horns extending up to the dentino-enamel junction in both primary and permanent dentition. CONCLUSION: XLH patients show some peculiar dentinal abnormalities. Treatment prevents only in part dental and periodontal lesions. Genetic mechanisms have a main role in causing defective dentin mineralisation.

Effect of GH treatment on bone mass in children with GH deficiency.

Children with GH deficiency have reduced bone mass and mineral density in comparison with normal individuals. GH treatment improves the accrual of bone mass during childhood and adolescence, but suboptimal GH treatment may cause a reduced bone mass in adulthood. At final height, treated patients with GH deficiency have normal mean values of bone mass, but some patients showed reduced lumbar bone mineral density (BMD) values. Lumbar peak bone mass (PBM) in treated patients who discontinued the treatment at final height is delayed and reduced. GH treatment during the transition from late adolescence to young adulthood can increase bone mass and mineral density. In patients with GH deficiency a possible strategy for avoiding acquisition of a suboptimal bone mass in the young-adult, could be to continue GH treatment during the transition to adulthood up to the acquisition of PBM.

From bone biology to bone analysis.

Bone development is one of the key processes characterizing childhood and adolescence. Understanding this process is not only important for physicians treating pediatric bone disorders, but also for clinicians and researchers dealing with postmenopausal and senile osteoporosis. Bone densitometry has great potential to enhance our understanding of bone development. The usefulness of densitometry in children and adolescents would be increased if the physiological mechanisms and structural features of bone were given more consideration in the design and interpretation of densitometric studies. This review gives an overview on the most relevant techniques of quantitative noninvasive bone analysis. Furthermore it describes the relationship between bone biology, selected surrogates describing the biological processes and the possibilities of measuring these surrogates specifically and precisely by the different devices. The overall recommendation for researchers in this field is to describe firstly the biological process to be analyzed (bone growth in length, remodeling or modeling, or all together), secondly the bone parameter which describes this process, and thirdly the reason for selecting a special device.

Indications and strategies for continuing GH treatment during transition from late adolescence to early adulthood in patients with GH deficiency: the impact on bone mass.

GH plays an important role in longitudinal bone growth and maturation during childhood and adolescence. However, GH has important metabolic functions other than bone growth, which become more apparent during young adulthood, when growth has been completed. Indeed, GH deficiency (GHD) in adult life is a recognized clinical syndrome which includes symptoms such as increased central adiposity, decreased lean body mass, reduced bone mineral density (BMD), increased atherogenic risk, cerebrovascular and cardiac morbidity and mortality, and reduced quality of life. As approximately one quarter of the children with GHD should continue GH administration in adulthood, it is important to reconfirm GHD at the end of growth in order to select patients with severe GHD who need to resume GH therapy with an appropriate age-related dosage. Some evidence indicates that most peak bone mass (PBM) is achieved by the end of adolescence but small increases in BMD continue during the period of transition from late adolescence to young adulthood. Some young adults with GHD show a persistent increase of lumbar BMD after the completion of growth even after discontinuation of treatment suggesting a spontaneous progression towards lumbar PBM or a continuing effect of the treatment. The data indicates that adolescents with GHD who do not reach lumbar PBM at the time of discontinuation of GH treatment can achieve a BMD lower than their genetic potential if they are not treated during the transition to young adulthood.

Hormonal treatment for unilateral inguinal testis: comparison of four different treatments.

BACKGROUND: Hormonal treatment of cryptorchidism has been used since the 30s, but controversies persist on its efficacy. It is also unclear whether there are differences with the use of different hormonal trials. AIMS: To evaluate the efficacy of four hormonal treatments on testicular descent in a homogeneous group of cryptorchid boys. PATIENTS: 155 patients (age 10-48 months) with unilateral inguinal palpable testis were studied. METHODS: The patients were subdivided into four groups according to hormonal treatment: group 1 = hCG [500 IU/week (if the chronological age was <2 years) or 1,000 IU/week (if the chronological age was >2 years) for 6 weeks]; group 2 = hCG + hMG (hCG as in group 1 + hMG 75 IU/week for 6 weeks); group 3 = GnRH (1,200 microg/daily for 28 days); group 4 = GnRH + hCG (1,200 microg/daily for 28 days + 1,500 IU/week for 3 weeks, respectively). The results were evaluated at the end of the treatment period and 6 months later to exclude temporarily positive results. RESULTS: At the end of the hormonal therapy, scrotal testicular descent was present in 30 of 155 boys (success rate 19.3%). Seven testes relapsed during follow-up (23.3%). The long-term success rate was 14.8% (23/155 testes). No significant differences were observed in success rates as well as in relapse rates among the four groups. CONCLUSIONS: Hormonal therapy induced permanent testicular descent in a minority of young cryptorchid boys with inguinal palpable testis. Similar results were obtained with four different trials.