Diagnosis, treatment and genetic analysis of two cases of congenital hyperinsulinemic hypoglycemia caused by GCK gene mutation.

Congenital hyperinsulinemia (CHI) is a heterogeneous disorder characterized by persistent hypoglycemia due to inappropriate insulin secretion. A total of 15 gene mutations have already been reported to be associated with CHI. Among them, CHI caused by the GCK mutation is named GCK-CHI, which is considered to be a rare form of CHI. Here, we reported two cases of GCK-CHI diagnosed by genetic testing and summarized the clinical characteristics. In patients with recurrent or persistent hypoglycemia, CHI should be taken into consideration. Genetic testing should be perfomed in these patients to avoid misdiagnosis and provide accurate intervention, thus to improve prognosis.

Diagnosis, Genetics, and Management of 24 Patients With Cardiac Paragangliomas: Experience From a Single Center.

Context: Paragangliomas located within the pericardium represent a rare yet challenging clinical situation. Objective: The current analysis aimed to describe the clinical characteristics of cardiac paragangliomas, with emphasis on the diagnostic approach, genetic background, and multidisciplinary management. Methods: Twenty-four patients diagnosed with cardiac paraganglioma (PGL) in Peking Union Medical College Hospital, Beijing, China, between 2003 and 2021 were identified. Clinical data was collected from medical record. Genetic screening and succinate dehydrogenase subunit B immunohistochemistry were performed in 22 patients. Results: The median age at diagnosis was 38 years (range 11-51 years), 8 patients (33%) were females, and 4 (17%) had familial history. Hypertension and/or symptoms related to catecholamine secretion were present in 22 (92%) patients. Excess levels of catecholamines and/or metanephrines were detected in 22 (96%) of the 23 patients who have completed biochemical testing. Cardiac PGLs were localized with 131I-metaiodobenzylguanidine scintigraphy in 11/22 (50%), and 99mTc-hydrazinonicotinyl-tyr3-octreotide scintigraphy in 24/24 (100%) patients. Genetic testing identified germline SDHx mutations in 13/22 (59%) patients, while immunohistochemistry revealed succinate dehydrogenase (SDH) deficiency in tumors from 17/22 (77%) patients. All patients were managed by a multidisciplinary team through medical preparation, surgery, and follow-up. Twenty-three patients received surgical treatment and perioperative death occurred in 2 cases. Overall, 21 patients were alive at follow-up (median 7.0 years, range 0.6-18 years). Local recurrence or metastasis developed in 3 patients, all of whom had SDH-deficient tumors. Conclusion: Cardiac PGLs can be diagnosed based on clinical manifestations, biochemical tests, and appropriate imaging studies. Genetic screening, multidisciplinary approach, and long-term follow-up are crucial in the management of this disease.