Endocrine Abstracts

JOINT941

Background: Hyperinsulinemic hypoglycemia is a common cause of hypoglycemia in neonates and infants, with several etiologies including syndromic disorders such as Turner syndrome. Turner syndrome linked to glycaemic dysregulation, including diabetes mellitus and, less typically, neonatal hyperinsulinemic hypoglycemia. Turner syndrome and hyperinsulinism are linked by an unknown aetiology.

Case Presentation: We report the case of a 4.5-year-old girl who developed a seizure at the age of 3 months as a result of hypoglecemia. She was born at term, weighing 3,120 g, with AGA. At a blood glucose level of 34 mg/dL, the critical blood sample revealed insulin 3.0 uIU/mL, serum ketones < 0.3 mmol/l, growth hormone (GH) 9.81 ng/mL, and cortisol 16.6 ng/dL. As a result, hyperinsulinemic hypoglycemia is diagnosed, and she has now begun therapy with Diazoxide at a dose of 10 mg/kg/day. The Diazoxide dose has been titrated based on blood sugar, and the most current dose is 3.5 mg/kg/day, which is well managed. A whole genome sequencing investigation for common hyperinsulinism target genes yielded no results. Height velocity has diverged from the 3^rd percentile from the age of two, with an average annual height gain of 3.3 cm. At the age of 4.5 years, her height was 91 cm (-3.4 SDS), her BW was 13.5 kg (-1.7 SDS). The paternal and maternal height are 178 and 160 cm, respectively and mid-parental height is 162.5 cm. The normal workup for short stature was completed, including a karyotype analysis. Mild dysmorphic characteristics, such as a bilateral epicanthal fold, clinodactyly in both hands, and hyperconvex nails, were discovered, but otherwise are unremarkable. A film X-ray of the hand reveals slight shortening of the 4^th metacarpal bone. A karyotype examination of 50 metaphases found mosaic Turner syndrome with a marker chromosome (46,X,dup(X)(q22q28)/45,X(1)/46,X,+mar(1)).

Discussion: Unlike usual cases of congenital hyperinsulinism, which are linked with increased height and weight, this individual had short stature and borderline low weight, indicating Turner syndrome. Reports from case series and case reports in the literature suggest a link between Turner syndrome and hyperinsulinism, albeit the mechanism is unknown. Some instances have been associated with islet cell nucleomegaly and KDM6A haploinsufficiency.

Conclusion: This report emphasizes the significance of examining Turner syndrome in females who appear with unexplained hyperinsulinemic hypoglycemia, especially when coupled with growth failure. More study is needed to understand the processes driving hyperinsulinism in Turner syndrome.