Endocrinopathy due to proproteinkovertase 1/3 deficiency: primary enteropathy, diabetes insipidus, secondary hypothyroidism

Proprotein convertase 1/3 (PC1/3) deficiency is an autosomal recessive disease caused by rare mutations in the proprotein convertase subtilisin/kexin type 1 (PCSK 1)gene, associated with severe malabsorptive diarrhea, obesity and some endocrine abnormalities. Proprotein convertase 1/3 is acalcium-dependent serine endoprotease involved in the proteolytic processing of various prohormones (peptide hormones in enteroendocrine cells that are necessary for the absorption of nutrients and is also expressed in the arcuate and paraventricular nuclei of the hypothalamus, in the beta cells of the pancreas) in their bioactive forms. The onset of the disease in the neonatal period of life is characterized by aclinical picture of severe malabsorption diarrhea, accompanied by developmental delays, and requires long-term parenteral nutrition. As the disease progresses, additional endocrine abnormalities develop, including diabetes insipidus, growth hormone deficiency, primary hypogonadism, adrenal insufficiency, hypothyroidism, and obesity. We conducted aprospective observation of apatient with agenetic disease due to proprotein convertase 1/3 deficiency confirmed during follow-up. The patient was examined and treated at the State Novosibirsk Regional Clinical Hospital in Novosibirsk for 11 months, with repeated (3-fold) hospitalizations. Purpose: to demonstrate the features of the onset and course of the disease, as well as the difficulties in verifying the clinical diagnosis of an ultra-rare genetic disease from the category of endocrinopathies, the complexity of medical support and therapy. Apeculiarity of this case is the fact that the identified mutation in the gene was not previously registered in control Russian samples of the genetic mutation of proprotein convertase 1/3 deficiency, as well as apreviously undescribed variant of the nucleotide sequence in exon 4 of the PCSK1 gene in aheterozygous state and was not registered in control samples gnomAD and RUSeq. Proprotein convertase 1/3 deficiency is adisease that is amultidisciplinary problem, since etiopathogenetic therapy has not yet been developed. The disease has achronic course with constant relapses of intestinal syndrome, is difficult to manage with symptomatic treatments and, as it progresses, has ahigh risk of developing additional endocrinopathies and death. All of the above emphasizes the need for early diagnosis and selection of rational replacement and accompanying therapy to save the lives of patients.