Case Report Hyperinsulinemic Hypoglycaemia in a Turner Syndrome with Ring (X) Michela Cappella, 1 Vanna Graziani, 1 Antonella Pragliola, 2 Alberto Sensi, 2 Khalid Hussain, 3 Claudia Muratori, 1 and Federico Marchetti 1 1 Department of Paediatrics, Santa Maria delle Croci Hospital, 48121 Ravenna, Italy 2 Department of Clinical Pathology, Medical Genetics Unit, Pievesestina, 47522 Cesena, Italy 3 London Centre for Pediatric Endocrinology and Metabolism, Great Hormond Street Hospital for Children NHS Trust and the Institute of Child Health, London WC1N 3JH, UK Correspondence should be addressed to Federico Marchetti; federico.marchetti@ausl.ra.it Received 30 January 2015; Accepted 13 April 2015 Academic Editor: Ozgur Cogulu Copyright © 2015 Michela Cappella et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Hyperinsulinemic hypoglycaemia (HH) is a group of clinically, genetically, and morphologically heterogeneous disorders characterized by dysregulation of insulin secretion by pancreatic beta cells. HH can either be congenital genetic hyperinsulinism or associated with metabolic disorder and syndromic condition. Early identiication and meticulous management of these patients is vital to prevent neurological insult. here are only three reported cases of HH associated with a mosaic, r(X) Turner syndrome. We report the four cases of an infant with a mosaic r(X) Turner genotype and HH responsive to diazoxide therapy. 1. Introduction Hyperinsulinaemic hypoglycaemia (HH) is an important cause of hypoglycaemia in childhood based on an unregu- lated insulin secretion by  cells [1]. Early identiication and meticulous management of these patients is vital to prevent neurological insult. We report a case of a child with a mosaic genotype of Turner’s syndrome in association with otherwise unexplained persistent HH. his association suggests that HH may be another atypical feature of mosaic Turner’s syndrome. 2. Case Report We report a case of a girl, born preterm at 32 weeks of gestation by caesarean section due to intrauterine growth retardation and alteration of fetal blood low. Her birth weight was 1455 g(10th–25th centile), length was 40 cm (10th– 25th centile), and head circumference was 27 cm (10th). he pregnancy was uneventful and her mother was healthy and nondiabetic. Her family history was unremarkable. Prenatal ultrasound scans were negative, without any evidence of heart disease. Soon ater birth a diagnosis of aortic stenosis with bicuspid aortic valve was made and, at the age of three weeks, she underwent aortic valvuloplasty. Neonatal metabolic screening was normal. No episodes of neonatal hypoglycaemia were documented. Ater discharge she had no serious illnesses or hospitalization, the cardiologic follow-up was carried out without complications, and she had been growing and developing normally. At 11 months of age, during her irst feed in the morning, she presented an episode of generalized tonic-clonic seizures and staring that lasted ive minutes. he episode was not associated with fever or any sign of infection. By the time she arrived at our emergency department, she was a little drowsy, but she could be awakened easily. Because of her previous history of congenital cardiac defect, we immediately performed an echocardiogram and an electrocardiogram although they did not show any cardiovas- cular acute disease. Respiratory, abdominal, and neurologic examinations were normal. A complete blood count, C- reactive protein, and electrolyte panel were normal but hypo- glycaemia with a blood glucose concentration of 1.8 mmol/l Hindawi Publishing Corporation Case Reports in Pediatrics Volume 2015, Article ID 561974, 4 pages http://dx.doi.org/10.1155/2015/561974