New features in a rare monogenic obesity: CPE DEFICIENCY.

Abstract

Introduction: CarboxypeptidaseE (CPE) is an enzyme involved in the neuropepetides/hormones processing. Its deficiency is associated with endocrinopathies comparable to those caused by proprotein convertase1/3(PC1/3) deficiency. In this case report we expand the clinical features of CPE deficiency by examining the index case's clinical/laboratory results, which are also indicative of PC1/3 deficiency.

Case presentation: The index case, 13.5 years old, had obesity, central hypothyroidism, developmental delay, hypogonadotropic hypogonadism, enuresis. A four-hour oral-glucose-tolerance-test revealed glucose intolerance with a partial insulin deficiency and postprandial hypoglycemia. Proinsulin level was high. Partial central diabetes insipidus was verified with a water-deprivation-test. Administration of desmopressin successfully alleviated the symptoms of polyuria-polydipsia and enuresis. Brain-derived-neurotrophic-factor level, which might be linked to ID, was low. The eight-month-old sibling had central hypothyroidism and hypotonicity,but has not yet developed obesity.

Conclusion: Patients with CPE deficiency should undergo evaluation not only for hypothyroidism and hypogonadism but also for glucose and water metabolism disorders. The presentation of new cases may lead to the discovery of novel findings, and the identification of other pituitary hormone deficiencies.