Exercise-induced hyperinsulinism, also known as monocarboxylate transporter 1 hyperinsulinemia, is a rare subtype of congenital hyperinsulinism caused by gain-of-function variants in the SLC16A1 gene, which encodes monocarboxylate transporter 1. Fewer than 20 cases have been reported in the literature. In this review, the genetic pathogenesis, current diagnosis, and treatment of exercise-induced hyperinsulinism are systematically reviewed to improve clinicians' understanding of the disease. 运动诱发性高胰岛素血症，也称为单羧酸转运体1型高胰岛素血症，是一种罕见的先天性高胰岛素血症亚型，由编码单羧酸转运体1的SLC16A1基因功能获得性变异所致。目前文献报道的病例不足20例。该文对运动诱发性高胰岛素血症的遗传发病机制、当前诊断和治疗进行系统综述，以提高临床医生对该病的认识。.

Rare defects in the promoter region of SLC16A1, the gene encoding monocarboxylate transporter 1 (MCT-1), result in exercise-induced hyperinsulinism. In this disorder, inappropriate insulin secretion is triggered by anaerobic exercise with consequent hypoglycaemia. We describe the case of a 41-year-old man presenting with a generalised tonic-clonic seizure and severe hypoglycaemia following strenuous exercise. A subsequent prolonged fast with incorporation of exercise into the protocol demonstrated hyperinsulinaemic hypoglycaemia; genetic testing revealed a variant of unknown significance in the SLC16A1 gene. Administration of subcutaneous octreotide resulted in dose-dependent reduction in hyperinsulinaemia and hypoglycaemia.

Hypoglycemia is defined by a low blood glucose level associated to clinical symptoms. Hypoglycemia may be related to treatment of diabetes, but also to drugs, alcohol, critical illness, cortisol insufficiency including hypopituitarism, insulinoma, bariatric or gastric surgery, pancreas transplantation or glucagon deficiency, or may be surreptitious. Some hypoglycemic episodes remain unexplained, and genetic, paraneoplastic and immune causes should be considered. Genetic causes may be related to endogenous hyperinsulinism and to inborn errors of metabolism (IEM). Endogenous hyperinsulinism is related to monogenic congenital hyperinsulinism, and especially to mutations of the glucokinase-activating gene or of insulin receptors, both characterised by postprandial hypoglycemia with major hyperinsulinism. In adulthood, IEM-related hypoglycemia can persist in a previously diagnosed childhood disease or may be a presenting sign. It is suggested by systemic involvement (rhabdomyolysis after fasting or exercising, heart disease, hepatomegaly), sometimes associated to a family history of hypoglycemia. The timing of hypoglycemic episodes with respect to the last meal also helps to orientate diagnosis. Fasting hypoglycemia may be related to type 0, I or III glycogen synthesis disorder, fatty acid oxidation or gluconeogenesis disorder. Postprandial hypoglycemia may be related to inherited fructose intolerance. Exercise-induced hyperinsulinism is mainly related to activating mutation of the SLC16A1 gene. Besides exceptional ectopic insulin secretion, paraneoplastic causes involve NICTH (Non-Islet-Cell Tumour Hypoglycemia), caused by Big-IGF2 secretion by a large tumour, with low blood levels of insulin, C-peptide and IGF1. Autoimmune causes involve antibodies against insulin (HIRATA syndrome), especially in case of Graves' disease, or against the insulin receptor. Medical history, timing, and insulin level orientate the diagnosis.