Severe hypoglycemia with Hyperprolinemia and Pituitary Stalk Interruption Syndrome in a 5-year-old boy: A Case Report and Literature Review

Background: Hyperprolinemia is a rare autosomal recessive disorder with two distinct types: I (HPI) and II (HPII). The clinical presentation varies widely, with some individuals remaining asymptomatic and others exhibiting neurological, renal or auditory defects and seizures. However, it has never been associated with hypoglycemia. The present case report describes a boy with HPII, with an episode of severe hypoglycemia and Pituitary Stalk Interruption Syndrome (PSIS) with isolated growth hormone (GH) deficiency (GHD). Case presentation: A 5-year and 6/12-month-old boy presented to the Department of Pediatric Endocrinology for routine thyroid function assessment due to hypothyroidism. He was diagnosed as having HPII at the age of 2 years during an investigation for seizure episodes. Clinically, the boy exhibited attention deficit hyperactivity disorder (ADHD) and a reduction in growth velocity (1.6 cm/year). Hematological and biochemical analyses were within the reference range. Hormone profiling revealed lower-than-expected insulin-like growth factor-1 (IGF-1) concentrations, prompting a GH stimulation test, which, in turn, revealed GHD. Brain magnetic resonance imaging (MRI) showed features consistent with PSIS. Noteworthy is the occurrence of severe hypoglycemia during the evaluation, leading to hospitalization, eventually attributed to GHD. Following the exogenous administration of recombinant human GH, the boy exhibited increased growth velocity, with no adverse events over the follow-up period. Conclusion: Hyperprolinemia is a rare condition; in this context, the occurrence of severe hypoglycemia accompanied by a low growth velocity poses a challenge for the clinical pediatrician.