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Context Familial short stature (FSS) is a term describing a growth disorder that is vertically transmitted. Milder forms may result from the combined effect of multiple genes; more severe short stature is suggestive of a monogenic condition. The etiology of most FSS cases has not been thoroughly elucidated to date. Objectives To identify the genetic etiology of severe FSS in children treated with GH because of the diagnosis of small for gestational age or GH deficiency (SGA/GHD). Design, Settings, and Patients Of 736 children treated with GH because of GHD/SGA, 33 with severe FSS (life-minimum height −2.5 SD or less in both the patient and shorter parent) were included in the study. The genetic etiology was known in 5 of 33 children prior to the study [ACAN (in 2], NF1, PTPN11, and SOS1). In the remaining 28 of 33, whole-exome sequencing was performed. The results were evaluated using American College of Medical Genetics and Genomics standards and guidelines. Results In 30 of 33 children (90%), we found at least one variant with potential clinical significance in genes known to affect growth. A genetic cause was elucidated in 17 of 33 (52%). Of these children, variants in growth plate-related genes were found in 9 of 17 [COL2A1, COL11A1, and ACAN (all in 2), FLNB, FGFR3, and IGF1R], and IGF-associated proteins were affected in 2 of 17 (IGFALS and HMGA2). In the remaining 6 of 17, the discovered genetic mechanisms were miscellaneous (TRHR, MBTPS2, GHSR, NF1, PTPN11, and SOS1). Conclusions Single-gene variants are frequent among families with severe FSS, with variants affecting the growth plate being the most prevalent.

Objective: Data on closed loop systems in young children with type 1 diabetes (T1D) are limited. We tested the efficacy and safety of an open-source, do-it-yourself automated insulin delivery system AndroidAPS in preschool and school-aged children.Research Design and Methods: This retrospective study analyzed diabetes control in 18 preschool (3-7 years) and 18 school-aged children (8-14 years) with T1D who switched from a sensor-augmented pump (SAP) to AndroidAPS. We compared the CGM parameters and HbA1c levels 3 months before and 6 months after the initiation of AndroidAPS therapy and evaluated frequency of severe adverse events during AndroidAPS use, the most frequent reasons for its interruption, and the experience and psychosocial benefits of AndroidAPS use.Results: General glycemic control was significantly improved after the switch from SAP to AndroidAPS. Time in range (TIR) increased in both preschool (70.8%-78.6%, p = 0.004) and school-aged children (77.2%-82.9%, p < 0.001), whereas HbA1c levels decreased (preschool children 53.8-48.5 mmol/mol, p < 0.001; school-aged children 52.6-45.1 mmol/mol, p = 0.001). Time spent in range of 3.0-3.8 mmol/L increased slightly in school children (2.6%-3.8%, p = 0.040), but not in preschool children (3.0%-3.0%, p = 0.913). Time spent at <3 mmol/L remained unchanged in both preschool (0.95%-0.67%, p = 0.432) and school-aged children (0.8%-0.8%, p = 1.000).No episodes of severe hypoglycemia or DKA and significant improvement of quality of life were reported by AndroidAPS users.Conclusions: AndroidAPS seems effective for T1D control both in preschool and school-age children but further validation by prospective studies is necessary.

Context The C-type natriuretic peptide receptor encoded by the NPR2 gene is a paracrine regulator of the growth plate; heterozygous NPR2 variants cause short stature with possible presence of different signs of bone dysplasia. To date, the effect of growth hormone (GH) treatment has been described in a few individuals with NPR2 gene variants with inconsistent results. Objectives To identify NPR2 gene variants among children with familial short stature (FSS) and to describe their phenotype, including GH treatment response. Design, Settings and Patients Out of 747 patients with short stature treated with GH in a single center, 87 with FSS met the inclusion criteria (pretreatment height ≤ –2 standard deviation in both the patient and the shorter parent, unknown genetic etiology). Next-generation sequencing methods were performed to search for NPR2 gene variants. The results were evaluated using the American College of Medical Genetics and Genomics guidelines. The GH treatment response (growth velocity improvement and height standard deviation score development over the first 5 years of treatment) was evaluated. Results In 5/87 children (5.7%), a (likely) pathogenic variant in the NPR2 gene was identified (p.Ile558Thr [in 2], p.Arg205*, p.Arg557His, p.Ser603Thr). Two children had disproportionate short-limbed short stature, 1 a dysplastic 5th finger phalanx. The growth velocity in the first year of GH treatment accelerated by 3.6 to 4.2 cm/year; the height improved by 1.2 to 1.8 SD over 5 years of treatment. Conclusions NPR2 gene variants cause FSS in a significant proportion of children. Their GH treatment response is promising. Studies including final height data are necessary to assess the long-term efficacy of this therapy.