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Context Severe forms of growth hormone insensitivity (GHI) are characterized by extreme short stature, dysmorphism, and metabolic anomalies. Objective This work aims to identify the genetic cause of growth failure in 3 “classical” GHI individuals. Methods A novel intronic growth hormone receptor gene (GHR) variant was identified, and in vitro splicing assays confirmed aberrant splicing. A 6Ω pseudoexon GHR vector and patient fibroblast analysis assessed the consequences of the novel pseudoexon inclusion and the impact on GHR function. Results We identified a novel homozygous intronic GHR variant (g.5:42700940T > G, c.618+836T > G), 44 bp downstream of the previously recognized intronic 6Ψ GHR pseudoexon mutation in the index patient. Two siblings also harbored the novel intronic 6Ω pseudoexon GHR variant in compound heterozygosity with the known GHR c.181C > T (R43X) mutation. In vitro splicing analysis confirmed inclusion of a 151-bp mutant 6Ω pseudoexon not identified in wild-type constructs. Inclusion of the 6Ω pseudoexon causes a frameshift resulting in a nonfunctional truncated GHR lacking the transmembrane and intracellular domains. The truncated 6Ω pseudoexon protein demonstrated extracellular accumulation and diminished activation of STAT5B signaling following GH stimulation. Conclusion Novel GHR 6Ω pseudoexon inclusion results in loss of GHR function consistent with a severe GHI phenotype. This represents a novel mechanism of Laron syndrome and is the first deep intronic variant identified causing severe postnatal growth failure. The 2 kindreds originate from the same town in Campania, Southern Italy, implying common ancestry. Our findings highlight the importance of studying variation in deep intronic regions as a cause of monogenic disorders.

Context Acute kidney injury (AKI) and renal tubular damage (RTD), especially if complicated by acute tubular necrosis (ATN), could increase the risk of later chronic kidney disease. No prospective studies on AKI and RTD in children with type1diabetes mellitus (T1DM) onset are available. Objectives To evaluate the AKI and RTD prevalence and their rate and timing of recovery in children with T1DM onset. Design Prospective study. Settings and patients 185 children were followed up after 14 days from T1DM onset. The patients who did not recover from AKI/RTD were followed-up 30 and 60 days later. Main outcome measures AKI was defined according to the KDIGO criteria. RTD was defined by abnormal urinary beta-2-microglobulin and/or neutrophil gelatinase-associated lipocalin and/or tubular reabsorption of phosphate 2%. ATN was defined by RTD+AKI, prerenal (P)-AKI by AKI+FENa Results Prevalence of diabetic ketoacidosis (DKA) and AKI were 51.4% and 43.8%, respectively. Prevalence of AKI in T1DM patients with and without DKA was 65.2% and 21.1%, respectively; 33.3% reached AKI stage 2, and 66.7% of patients reached AKI stage 1. RTD was evident in 136/185 (73.5%) patients (32.4% showed ATN; 11.4%, P-AKI; 29.7%, ATD). All patients with DKA or AKI presented with RTD. The physiological and biochemical parameters of AKI and RTD were normal again in all patients. The former within 14 days and the latter within 2months. Conclusions Most patients with T1DM onset may develop AKI and/or RTD, especially if presenting with DKA. Over time the physiological and biochemical parameters of AKI/RTD normalize in all patients.

Context: Studies examining vitamin D levels in association with childhood obesity usually do not consider the effect of insulin on vitamin D–binding protein and do not calculate the unbound, bioavailable vitamin D. Objective: This study aimed to evaluate in a group of children 1) the concentrations of both total 25-hydroxyvitamin D and bioavailable fraction, and 2) the potential role of insulin resistance in modulating the concentrations of bioavailable vitamin D. Design, Setting, and Patients or Other Participants: This was a cross-sectional study at a University Pediatric Department in which 63 obese children and 21 lean controls were enrolled. Main Outcome Measures: Total 25-hydroxyvitamin D and vitamin D–binding protein were measured, twosingle-nucleotide polymorphisms in the coding region of the vitaminD–binding protein (rs4588 and rs7041) were studied, and the vitamin D bioavailable fraction was calculated. Results: Obese children showed total 25-hydroxyvitamin D levels lower compared with nonobese children (21.36.7 ng/mL vs 29.611.7 ng/mL; P.0004). Bioavailable 25-hydroxyvitaminDlevels were not different among the two groups (3.1 1.6 ng/mL vs 2.6 1.2 ng/mL; P .05). Insulinresistant children showed higher bioavailable levels of 25-hydroxyvitamin D compared with noninsulin- resistant children (3.4 1.4 ng/mL vs 2.0 0.9 ng/mL; P .013) and an inverse correlation between insulin resistance and vitamin D–binding protein was found (r: 0.40; P .024). Conclusions: Obese children present levels of bioavailable 25-hydroxyvitamin D similar to those of normal-weight children due to reduced concentration of vitamin D–binding protein. The insulin resistance could play a role in this reduced concentrati

Objective: The insulin variable number of tandem repeats (VNTR) polymorphism located in the insulin gene promoter (INS VNTR) has been associated with insulin levels in obese children. Hyperinsulinemia is a pivotal factor in the development of metabolic syndrome, an emerging complication in childhood obesity. With the present study, we aimed to test the associations between INS VNTR and the metabolic syndrome in juvenile-onset obesity. Subjects and Methods: We screened for the INS VNTR in 320 obese children (152 girls; mean age, 11.2 ± 2.3 yr; mean z-score body mass index, 3.6 ± 1.1). All of them underwent a standard oral glucose tolerance test; baseline measurements included blood pressure and plasma lipid and fasting insulin levels. By using the data derived from the oral glucose tolerance test, the whole-body insulin sensitivity and the insulinogenic index were calculated. Results: The prevalence of metabolic syndrome reached 39%. No differences in INS VNTR genotype distribution were observed between obese subjects and 200 lean, age- and sex-matched children (P = 0.7). Among obese subjects, the prevalence of the metabolic syndrome was significantly higher in subjects with the I/I genotype (P = 0.006); the risk for developing the metabolic syndrome was significantly higher in subjects carrying the I/I genotype (odds ratio, 2.5; 95% confidence interval, 1.5–3.9). Obese subjects homozygous for the class I allele showed higher insulin levels and insulinogenic index but lower whole-body insulin sensitivity. Conclusions: We conclude that the I variant of the insulin promoter, when expressed in homozygotes, can predispose obese children to develop the metabolic syndrome.