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Abstract Objective Idiopathic infantile hypercalcemia (IIH) is a rare disorder of PTH-independent hypercalcemia. CYP24A1 and SLC34A1 gene mutations cause two forms of hereditary IIH. In this study, the clinical manifestations and molecular aspects of six new Chinese patients were investigated. Methods The clinical manifestations and laboratory study of six patients with idiopathic infantile hypercalcemia were analyzed retrospectively. Results Five of the patients were diagnosed with hypercalcemia, hypercalciuria, and bilateral medullary nephrocalcinosis. Their clinical symptoms and biochemical abnormalities improved after treatment. One patient presented at age 11 years old with arterial hypertension, hypercalciuria and nephrocalcinosis, but normal serum calcium. Gene analysis showed that two patients had compound heterozygous mutations of CYP24A1, one patient had a monoallelic CYP24A1 variant, and three patients had a monoallelic SLC34A1 variant. Four novel CYP24A1 variants (c.116G > C, c.287T > A, c.476G > A and c.1349T > C) and three novel SLC34A1 variants (c.1322 A > G, c.1697_1698insT and c.1726T > C) were found in these patients. Conclusions A monoallelic variant of CYP24A1 or SLC34A1 gene contributes to symptomatic hypercalcemia, hypercalciuria and nephrocalcinosis. Manifestations of IIH vary with onset age. Hypercalcemia may not necessarily present after infancy and IIH should be considered in patients with nephrolithiasis either in older children or adults.

Objective: Children born small for gestational age (SGA) are at a greater risk of developing insulin resistance, type 2 diabetes, and cardiovascular disease in adulthood. Gastrointestinal peptides, some secreted by intestinal L cells, regulate glucose and lipid metabolism and act on the hypothalamus to regulate energy homeostasis. The aim of this study was to explore whether gastrointestinal peptides are involved in metabolic disorders in SGA, which remains unclear. Methods: The secretion of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) were investigated in prepubertal children born SGA, the differences between catch-up growth and persistent short stature were compared, and correlation with glucose and lipid metabolism was analyzed. GLP-1, PYY, insulin-like growth factor 1, glucose, insulin, and lipid concentrations were analyzed in prepubertal children aged 4-10 years, stratified into three groups: short-SGA (SGA-s), catch-up growth SGA, and normal growth appropriate for gestational age (AGA). Results: Fasting GLP-1 and PYY concentrations were significantly lower in the SGA group than in the AGA group (p<0.05), and the GLP-1 level in infants born SGA with catch-up growth was lower than that in the SGA-s group (p<0.05). In the SGA population, GLP-1 showed a weak negative correlation with catch-up growth (r=-0.326) and positive correlation with fasting insulin (r=0.331). Conclusion: Lower GLP-1 concentrations may be associated with abnormal glucose metabolism in prepubertal children born SGA with catch-up growth. This is indirect evidence that impaired intestinal L cell function may be involved in the development of metabolic complications in SGA children. [ABSTRACT FROM AUTHOR]