Hyperinsulinaemic Hypoglycaemia and Polycystic Kidney Disease - A Rare Case Concerning PMM2 Gene Pleiotropy.

Co-occurrence of hyperinsulinaemic hypoglycaemia and polycystic kidney disease (HIPKD) has been recently described. It is caused by a non-coding variant in the promoter region for phosphomannomutase 2 (PMM2), c.-167G>T, both in homozygous or compound heterozygous variants with deleterious coding. Although PMM2 has been associated with congenital disorder of glycosylation, patients do not present with this phenotype and have normal carbohydrate-deficient transferring testing. The authors present a rare case where specific PMM2 study was performed as a result of clinical suspicions. The patient was a 6-year-old female followed at our clinic due to congenital hyperinsulinism since she was 1 month old. She also presented with bilateral polycystic kidneys, detected in prenatal set, and simple hepatic cysts, for which she was treated with diazoxide and captopril. Initial metabolic and genetic studies were normal. PMM2 gene sequence study revealed the promotor variant c.-167G>T in compound heterozygosity with the previously described pathogenic variant c.422G>A (p.Arg141His), confirming the diagnosis of HIPKD. This is a notable case as it highlights the importance of keeping this diagnostic hypothesis in mind and serves as a reminder to perform proper clinical and genetic investigation. A correct, and early, diagnosis will avoid unnecessary additional investigations and will allow appropriate genetic counselling for this autosomal recessive disorder.

BK virus nephropathy complicated with meningoencephalitis after kidney transplantation.

BK disease is an opportunistic infection in organ transplant recipients and patients with other cellular immunodeficiencies. To the best of our knowledge, we report the second case of BK meningoencephalitis associated with nephropathy in a kidney transplant recipient. A 15-yr-old boy underwent a cadaveric kidney transplant without complications; however, 11 wk after the transplantation, he was admitted to the hospital for graft dysfunction and cytopenia, which were confirmed by BK nephropathy (plasma viral replication and histological evidence). Four days after his hospital admission, he developed a high-grade fever and headache. CSF analysis revealed pleocytosis with a positive PCR for BK virus. Reduction in immunosuppression and supportive care conducting cycles of immunoglobulin and cidofovir were successful in treating the patient. BK meningoencephalitis should be considered in kidney transplant recipients who present with signs and symptoms of meningoencephalitis.

Post-transplantation encapsulating peritoneal sclerosis in a pediatric patient.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is a serious complication of long-term peritoneal dialysis (PD), but only a few cases have been described in the pediatric patient population. There is no established medical treatment, and surgery has been reported with variable success. The number of reports of EPS being successfully treated with tamoxifen, based on its anti-fibrotic effects, are increasing. The role of sirolimus, an mTOR inhibitor with immunomodulatory and anti-proliferative properties, has been less well-defined. CASE-DIAGNOSIS/TREATMENT: A 17-year-old kidney transplant recipient, with a previous cumulative time on PD of 8 years and 3 months, developed severe bowel obstruction 8 months after undergoing a second kidney graft. Her immunosuppressive regimen consisted of tacrolimus, mycophenolate mofetil, and prednisolone. The patient underwent laparotomy, which revealed multiple thick leathery adhesions with an encapsulated small bowel. Enterolysis was performed, and total parenteral nutrition was commenced after surgery to provide an adequate food intake. Treatment with tamoxifen was initiated, but the patient developed significant liver toxicity 2 weeks later, and the drug was withdrawn. The immunosuppressive regimen was changed to an increased dose of prednisolone, and tacrolimus was replaced with sirolimos. At 20 months of follow-up, the patient remains symptom-free, with a functioning kidney transplant. CONCLUSION: Although EPS is a very rare condition in the pediatric population, it should be considered when a child or adolescent with a long-term history of PD presents with nonspecific gastrointestinal symptoms or with signs of bowel obstruction. There is an urgent need for alternative immunosuppressive protocols. The use of sirolimus in this group of patients remains controversial.