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Context Burosumab has been approved for the treatment of children and adults with X-linked hypophosphatemia (XLH). Real-world data and evidence for its efficacy in adolescents are lacking. Objective To assess the effects of 12 months of burosumab treatment on mineral metabolism in children (aged Design Prospective national registry. Setting Hospital clinics. Patients A total of 93 patients with XLH (65 children, 28 adolescents). Main Outcome Measures Z scores for serum phosphate, alkaline phosphatase (ALP), and renal tubular reabsorption of phosphate per glomerular filtration rate (TmP/GFR) at 12 months. Results At baseline, patients showed hypophosphatemia (−4.4 SD), reduced TmP/GFR (−6.5 SD), and elevated ALP (2.7 SD, each P < .001 vs healthy children) irrespective of age, suggesting active rickets despite prior therapy with oral phosphate and active vitamin D in 88% of patients. Burosumab treatment resulted in comparable increases in serum phosphate and TmP/GFR in children and adolescents with XLH and a steady decline in serum ALP (each P < .001 vs baseline). At 12 months, serum phosphate, TmP/GFR, and ALP levels were within the age-related normal range in approximately 42%, 27%, and 80% of patients in both groups, respectively, with a lower, weight-based final burosumab dose in adolescents compared with children (0.72 vs 1.06 mg/kg, P < .01). Conclusions In this real-world setting, 12 months of burosumab treatment was equally effective in normalizing serum ALP in adolescents and children, despite persistent mild hypophosphatemia in one-half of patients, suggesting that complete normalization of serum phosphate is not mandatory for substantial improvement of rickets in these patients. Adolescents appear to require lower weight-based burosumab dosage than children.

Pediatric diabetes 23(8), 1602-1612 (2022). doi:10.1111/pedi.13450, Published by Wiley-Blackwell, Oxford [u.a.]

Use of continuous glucose monitoring (CGM) systems has become standard of care in type 1 diabetes (T1D) in many countries, particularly in children and adolescents (1,2). Results from clinical trials indicate that use of CGM leads to improved metabolic control and reduction in nonsevere hypoglycemia compared with self-monitoring of capillary blood glucose (3,4). Benefits are seen irrespective of insulin delivery method (pump or pen) (4,5) but are conditioned on near-daily sensor usage (4). Trial participants, however, are often biased toward higher education level, greater therapy adherence, and better self-management. Small sample size and short trial duration very often preclude appropriate assessment of CGM impact on rare events such as severe hypoglycemia (SH) or diabetic ketoacidosis (DKA). We therefore used real-world data from the German-Austrian-Swiss-Luxembourgian Diabetes Prospective Follow-up (DPV) registry to longitudinally assess HbA1c, SH, and DKA during the first year after initiation of CGM, including real-time CGM and intermittently scanned/viewed CGM. Anonymized patient registry records were analyzed. SH was defined as events requiring external assistance by another person and events resulting in coma/convulsion. DKA was defined by pH level

The differential diagnosis of 46,XY disorders of sex development (DSD) is based on the distinction between forms of gonadal dysgenesis and disorders of androgen biosynthesis and action. However, clinical and endocrine evaluations are often not conclusive. Here, we describe an adolescent female with hirsutism and hyperandrogenization at puberty. Her karyotype was 46,XY, and clinical investigation demonstrated clitoromegaly, but no uterine remnants were detected. Histology of the gonads revealed a testicular structure with a Sertoli-cell-only pattern. Endocrine evaluation showed hypergonadotropic hypogonadism, and the Sertoli cell markers inhibin B and anti-Müllerian hormone were also low. Several molecular genetic studies were initiated. While analyses of the androgen receptor gene, the SRD5A2 gene and HSD17B3 gene were uninformative, a novel p.L230R mutation was found in the NR5A1 gene. A mutant construct proved a severe dysfunction of this variant in functional analysis after recreation and transfection into HeLa cells. We conclude that the NR5A1 p.L230R mutation most likely leads to a spatial and time-dependent Leydig cell and Sertoli cell dysfunction during development not causing the classical gonadal dysgenesis phenotype. This case demonstrates that the current classification should be updated to encompass the overlapping phenotypes of some genetic conditions within 46,XY DSD.

Mutations in PAX8, a transcription factor gene, cause thyroid dysgenesis (TD). The extreme variability of the thyroid phenotype makes it difficult to identify individuals harboring PAX8 gene mutations. Here we describe two patients with TD and report two novel PAX8 gene mutations (S54R and R133Q). We performed in vitro studies to functionally characterize these mutations.Using PAX8 expression vectors, we investigated whether the PAX8 mutants localized correctly to the nucleus. To analyze the DNA-binding properties of S54R and R133Q, electrophoretic mobility shift assays were performed. Furthermore, we measured whether the mutant PAX8 proteins were able to activate the thyroglobulin (TG)- and the thyroperoxidase (TPO)-promoters.S54R had an impaired binding to DNA and a negligible activity on the TG- and the TPO-promoters. The DNA-binding property of R133Q, which is located in the highly conserved terminal portion of the PAX8 DNA-binding domain, was normal. Interestingly, it also exhibited dramatically impaired activation of the TG- and TPO-promoters. However, R133Q has no dominant negative effect on the WT protein in vitro. Thus, the underlying molecular mechanism by which the function of R133Q is impaired remains to be elucidated.We identified and functionally characterized two novel mutations of the PAX8 gene that lead to TD by distinct mechanisms. A structural defect of the mutant R133Q leading to a reduced capability for induced fit upon DNA interaction might explain the disparity between its apparently normal binding to DNA, but lack of promoter activation.

Constitutional ring chromosomes can be found for all human chromosomes and are very rare chromosomal abnormalities. A complete ring chromosome without loss of genetic material results from fusion of subtelomeric regions or telomere-telomere fusion. In cases of complete ring chromosome, an increased incidence of severe growth failure with no or only minor anomalies has been observed and attributed to ring syndrome. Ring syndrome is thought to be caused by "dynamic mosaicism" due to ring instability. We report a 6-year-old boy with de novo ring chromosome 4 and typical characteristics of the ring syndrome, namely, proportionate severe growth failure, microcephaly, and minor anomalies. Cytogenetic studies showed complete ring chromosome 4 with mitotic instability. Microarray gave normal results, thus excluding the loss of detectable genetic material. The literature of complete ring chromosome 4 is reviewed. Our case report supports the theory of ring syndrome. No studies about the effects and possible side effects of growth hormone therapy on patients with ring chromosomes have yet been published. We suggest that cytogenetic monitoring of the rate of secondary aberrations in patients with ring chromosome undergoing growth hormone therapy might be feasible. Since the diagnosis would have been missed by molecular karyotyping, our case report underlines the continuing role of classical cytogenetics for the evaluation of structural chromosomal abnormalities in patients with mental and/or physical anomalies. Standard karyotyping is still indispensable and should have an ongoing role as first-tier analysis together with molecular karyotyping. © 2017 Wiley Periodicals, Inc.

Identification of this additional patient from a distant part of the originally described pedigree (Synofzik et al. 2014) confirms pathogenicity of DNAJC3 mutations. Hypothyroidism is a newly identified feature in addition to the known phenotype (diabetes with multisystemic neurodegeneration).

The differential diagnosis of 46,XY disorders of sex development (DSD) is based on the distinction between forms of gonadal dysgenesis and disorders of androgen biosynthesis and action. However, clinical and endocrine evaluations are often not conclusive. Here, we describe an adolescent female with hirsutism and hyperandrogenization at puberty. Her karyotype was 46,XY, and clinical investigation demonstrated clitoromegaly, but no uterine remnants were detected. Histology of the gonads revealed a testicular structure with a Sertoli-cell-only pattern. Endocrine evaluation showed hypergonadotropic hypogonadism, and the Sertoli cell markers inhibin B and anti-Müllerian hormone were also low. Several molecular genetic studies were initiated. While analyses of the androgen receptor gene, the SRD5A2 gene and HSD17B3 gene were uninformative, a novel p.L230R mutation was found in the NR5A1 gene. A mutant construct proved a severe dysfunction of this variant in functional analysis after recreation and transfection into HeLa cells. We conclude that the NR5A1 p.L230R mutation most likely leads to a spatial and time-dependent Leydig cell and Sertoli cell dysfunction during development not causing the classical gonadal dysgenesis phenotype. This case demonstrates that the current classification should be updated to encompass the overlapping phenotypes of some genetic conditions within 46,XY DSD.

OBJECTIVE Type 1 diabetes and multiple sclerosis (MS) are typical autoimmune diseases in children and young adults. We assessed the co-occurrence of type 1 diabetes and MS by estimating the relative risk (RR) for MS in a pediatric and adolescent diabetic population and looked for possible influencing factors. RESEARCH DESIGN AND METHODS Within the Diabetes Patienten Verlaufsdokumentation (DPV)-Wiss Project, from January 1995 to October 2012, data from 56,653 patients with type 1 diabetes were collected in 248 centers in Germany and Austria. Published data on German and Mid-European MS prevalence were taken for comparison. Multivariable regression analysis was used to identify confounders for co-occurrence of type 1 diabetes and MS. RESULTS The RR for MS in patients with type 1 diabetes was estimated at 3.35–4.79 (95% CI 1.56–7.21 and 2.01–11.39, respectively). Immigration status in all patients (P < 0.05) and the presence of thyroid antibodies in male patients only (P = 0.05) were identified as influencing factors on MS incidence within the DPV database. The month-of-birth pattern revealed that risk was higher during the spring and summer months in the population with type 1 diabetes and MS in comparison with the population with type 1 diabetes. CONCLUSIONS The present cohort study demonstrates a higher risk of co-occurrence of MS in a pediatric and adolescent diabetic population. Immigration status and thyroid antibodies in male patients were independent risk indicators for the incidental rate of MS. Diabetic patients born during spring and summer had a higher risk for the development of MS. We suggest that environmental factors modulate the individual’s risk for the co-occurrence of both diseases.

Objective To obtain information on health and quality of life in adults with Noonan syndrome. Study design From a cohort of 144 children with the diagnosis of Noonan syndrome whose height data had been published 23 years ago, 103 pediatric files providing adequate data were identified. Participants were sent questionnaires and asked to provide saliva for DNA analysis and to return for physical examination. Results Ten of 103 individuals had died, 3 of them suddenly (standardized mortality ratio, 3.00; 95% CI, 1.44-5.52). Eighty-one individuals could be contacted by mail, with a positive response from 45. Genotyping in 36 of 45 participants revealed characteristic mutations in 61%. Median age at follow-up was 42.8 years. Mean adult heights were 169.2 cm (men) and 154.4 cm (women). In comparison with the general population, participants had lower educational status and lived more frequently without any partner. According to the response to the Short Form-36 questionnaire, quality of life was not impaired. Conclusions Individuals with Noonan syndrome have higher mortality, lower education, and rarely partnership. Quality of life according to self-reported Short Form-36 was good. Men grew taller than previously reported from this cohort.

Interstitial deletions of the distal part of chromosome 2p are rare, with only six reported cases involving regions from 2p23 to 2pter. Most of these were cytogenetic investigations. We describe a 14-year-old boy with an 8.97 Mb deletion of 2p23.3–24.3 detected by array comparative genomic hybridization (array CGH) who had intellectual disability (ID), unusual facial features, cryptorchidism, skeletal myopathy, dilated cardiomyopathy (DCM), and postnatal overgrowth (macrocephaly and tall stature). We compared the clinical features of the present case to previously described patients with an interstitial deletion within this chromosomal region and conclude that our patient exhibits a markedly different phenotype. Additional patients are needed to further delineate phenotype–genotype correlations © 2012 Wiley Periodicals, Inc.

Diabetes mellitus and neurodegeneration are common diseases for which shared genetic factors are still only partly known. Here, we show that loss of the BiP (immunoglobulin heavy-chain binding protein) co-chaperone DNAJC3 leads to diabetes mellitus and widespread neurodegeneration. We investigated three siblings with juvenile-onset diabetes and central and peripheral neurodegeneration, including ataxia, upper-motor-neuron damage, peripheral neuropathy, hearing loss, and cerebral atrophy. Exome sequencing identified a homozygous stop mutation in DNAJC3. Screening of a diabetes database with 226,194 individuals yielded eight phenotypically similar individuals and one family carrying a homozygous DNAJC3 deletion. DNAJC3 was absent in fibroblasts from all affected subjects in both families. To delineate the phenotypic and mutational spectrum and the genetic variability of DNAJC3, we analyzed 8,603 exomes, including 506 from families affected by diabetes, ataxia, upper-motor-neuron damage, peripheral neuropathy, or hearing loss. This analysis revealed only one further loss-of-function allele in DNAJC3 and no further associations in subjects with only a subset of the features of the main phenotype. Our findings demonstrate that loss-of-function DNAJC3 mutations lead to a monogenic, recessive form of diabetes mellitus in humans. Moreover, they present a common denominator for diabetes and widespread neurodegeneration. This complements findings from mice in which knockout of Dnajc3 leads to diabetes and modifies disease in a neurodegenerative model of Marinesco-Sjögren syndrome.