Härter, Bettina, Fuchs, Irene, Müller, Thomas, Akbulut, Ulas Emre, Cakir, Murat, and Janecke, Andreas R.
Autosomal recessive proprotein convertase 1/3 (PC1/3) deficiency, caused by mutations in the PCSK1gene, is characterized by severe congenital malabsorptive diarrhea, early-onset obesity, and certain endocrine abnormalities. We suspected PC1/3 deficiency in a 4-month-old girl based on the presence of congenital diarrhea and polyuria. Sequencing the whole coding region and splice sites detected a novel homozygous PCSK1splice-site mutation, c.544–2A>G, in the patient. The mutation resulted in the skipping of exon 5, the generation of a premature termination codon, and nonsense-mediated PCSK1messenger ribonucleic acid decay, which was demonstrated in complementary DNA derived from fibroblasts.