An asymptomatic patient has proteinuria and hematuria that is glomerular in origin on a routine urinalysis. Which of the following is the most likely diagnosis?

Other causes of asymptomatic hematuria, with or without proteinuria, include sickle cell disease, Alport's syndrome, resolving glomerulonephritis, and thin basement disease. Berger's disease is characterized by immunoglobulin A (IgA) deposits in the mesangium. It most commonly affects older children and young adults, and is more common in Blacks than Whites. Macroscopic hematuria may occur with inter-current illness or vigorous exercise. The prognosis is variable but tends to progress slowly. Spontaneous remissions are more common in children than in adults. About 20-50% of patients develop end-stage renal disease within 20 years of diagnosis.