Inherited renal diseases.
Genetic disorders of the kidney include cystic diseases, metabolic diseases and immune glomerulonephritis. Cystic diseases include autosomal dominant and recessive polycystic kidney disease (ADPKD, ARPKD, respectively). Neonates with enlarged, cystic kidneys should be evaluated for PKD. Patients with ADPKD have cysts and renal enlargement. Most patients present with hypertension, hematuria or flank pain; the most common extrarenal manifestation is polycystic liver disease. Oligohydramnios, bilaterally enlarged kidneys and decreased urine are featured in utero in ARPKD. Medullary sponge kidney is uncommon and features nephrocalcinosis, recurrent calcium stones and a history of polyuria/nocturia and/or urinary tract infections. Alport syndrome (AS) is an inherited disease of the glomerular basement membrane that is usually inherited as an X-linked dominant trait. Most patients with AS present in the first two decades of life with persistent microscopic or gross hematuria. Later, proteinuria is seen and its presence portends disease progression. Other findings may include sensorineural hearing loss and ocular abnormalities. There are various inherited tubulopathies, including Bartter syndrome, a group of renal tubular disorders that consist of two phenotypes with four genotypes. Patients usually present early in life with salt wasting, hypokalemia and metabolic alkalosis. Other features, depending on genotype, may include polyhydramnios and premature birth. Gitelman syndrome is also a salt-losing tubulopathy characterized by hypokalemic alkalosis. The majority of patients with Gitelman syndrome present during adolescence or early adulthood.