A well-described case report (B Harter et al. JPGN 2016; 62: 577-80) provides a description of proprotein convertase 1/3 (PC1/3) deficiency. To date, only 21 cases have been reported.
Clinical features: congenital diarrhea and polyuria; normal endoscopy/histology. This patient required parenteral nutrition until 11 months of age. Her polyuria resolved at 13 months of age. Low serum levels of c-peptide and insulin along with elevated pro-insulin, combined with the polyuria, were suspicious for PC1/3 deficiency. This patient’s diagnosis was established with genetic analysis of the PCSK1 gene.
PC1/3 is responsible for peptide hormone processing in endocrine cells in the gut, and has targets in the hypothalamus and pancreas. Growth hormone deficiency, adrenal insufficiency, diabetes insipidus, and hypogonadism are commonly observed.
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