ABSTRACT
BACKGROUND: Familial juvenile hyperuricemic nephropathy (FJHN) is a rare autosomal dominant disease caused by mutations in the uromodulin gene (UMOD) and leading to gout, tubulointerstitial nephropathy and end-stage renal disease. CASE REPORTS AND RESULTS: A Latvian family suffering from FJHN is described. The father of the family developed ESRD at age 36. His daughter was diagnosed with gout and chronic kidney disease at age 14 years. A renal biopsy revealed tubulointerstitial disease; 2 sons were diagnosed at age 9 and 4 with elevated uric acid levels and reduced fractional uric acid excretion. Urinary uromodulin was normal in the younger boy, but markedly decreased in the 2 other patients. Genetic analysis revealed a previously undescribed D196Y mutation in the UMOD gene. The female patient became pregnant at age 23. During pregnancy serum creatinine decreased from 2.0 to 1.5 mg/dl and blood pressure remained low. Analysis of the baby's umbilical cord blood and a mouth swab showed the presence of the D196Y mutation. Its urinary uromodulin excretion was in the low normal range. CONCLUSION: The uromodulin excretion pattern observed in the investigated family suggests that urinary uromodulin decreases in FJHN from low normal values at childhood to extremely low levels in early adulthood. In addition, this first report on pregnancy in a patient with FJHN shows normal adaptation despite markedly reduced renal function.
Subject(s)
Hyperuricemia/genetics , Kidney Diseases/genetics , Mucoproteins/genetics , Mutation/genetics , Pregnancy Complications/genetics , Adolescent , Age Factors , Child, Preschool , Female , Humans , Hyperuricemia/metabolism , Hyperuricemia/therapy , Infant, Newborn , Kidney Diseases/metabolism , Kidney Diseases/therapy , Male , Mucoproteins/metabolism , Pedigree , Pregnancy , Pregnancy Complications/metabolism , Pregnancy Complications/therapy , Pregnancy Outcome , Uromodulin , Young AdultABSTRACT
Childhood renal osteodystrophy (ROD) is the consequence of disturbances of the calcium-regulating hormones vitamin D and parathyroid hormone (PTH) as well as of the somatotroph hormone axis associated with local modulation of bone and growth cartilage function. The resulting growth retardation and the potentially rapid onset of ROD in children are different from ROD in adults. The biochemical changes of ROD as well as its prevention and treatment affect calcium and phosphorus homeostasis and are directly associated with the development of cardiovascular disease in pediatric renal patients. The aims of the clinical and biochemical surveillance of pediatric patients with CRF or on dialysis are prevention of hyperphosphatemia, avoidance of hypercalcemia and keeping the calcium phosphorus product below 5 mmol(2)/l(2). The PTH levels should be within the normal range in chronic renal failure (CRF) and up to 2-3 times the upper limit of normal levels in dialysed children. Prevention of ROD is expected to result in improved growth and less vascular calcification.
