PROPROTEIN CONVERTASE 1/3 DEFICIENCY WITH PELVIC EWING SARCOMA.

Proprotein convertase 1/3 (PC 1/3) deficiency is a rare, autosomal recessive disorder caused by mutations in the PCSK1 gene. The disease is characterized by early-onset chronic diarrhea/malabsorption, followed by severe obesity and hormonal deficiencies such as hypocortisolism, hypothyroidism, diabetes insipidus, hypogonadism, growth deficiency, and diabetes mellitus. Ewing's sarcoma is a rare tumor, usually of small dimensions of neuroectodermal origin that is difficult to distinguish pathologically from a primitive neuroectodermal tumor. A 22-year-old female patient with PC 1/3 deficiency was admitted to our clinic with recurrent urinary tract infections. Magnetic resonance imaging (MRI) revealed an 11x12 cm pelvic mass displacing the uterus. A core-needle biopsy was performed on the pelvic mass. As a result of the pathological evaluation, it was diagnosed with pelvic Ewing's sarcoma. The patient was started on the VAC-IE chemotherapy protocol. We report a case of pelvic Ewing's sarcoma in a patient with PC 1/3 deficiency. Further research is needed to assess malignancy risk in metabolic disorders including very rare disorders like PC 1/3 deficiency.

Diazoxide-Induced Neutropenia and Long-Term Follow-up in a Patient with Hyperinsulinemia-Hyperammonemia due to GLUD1 Mutation.

Hyperinsulinism/hyperammonemia (HI/HA) syndrome is caused by activating mutations in GLUD1 gene, and causes fasting as well as protein sensitive symptomatic hypoglycemia, in addition to persistently elevated plasma ammonia levels. First-line treatment is diazoxide, and most patients respond well to this agent, however side effects may be observed. The most frequent side effect of diazoxide is fluid retention and hypertrichosis, while hyperuricemia and hematologic side effects are observed less often. Herein, we report a case who had a heterozygous mutation of GLUD1 gene and who developed diazoxide related neutropenia 8 years after the start of treatment. On follow-up, leucopenia and mild neutropenia persisted and the treatment was changed to somatostatin analogues. However, she developed persistent severe symptomatic hypoglycemia and required diazoxide retreatment. A lower dose of diazoxide (6 mg/kg/day) successfully controlled hypoglycemia and cell counts increased even though they were not normalized. Neutropenia in current case presented after a long period of time of diazoxide use and this period is the longest defined in the literature. Long-term endocrine and hematologic follow-up of this patient up to 18 years old will also be presented.