A 40-year-old man with Alport syndrome presents with a 3-month history of headaches. His blood pressure is 165/100 mm Hg. A urinalysis shows 3+ proteinuria and 2+ hematuria. Laboratory studies disclose elevated levels of BUN (48 mg/dL) and creatinine (3.6 mg/dL). This patient's renal disease is caused by mutation in a gene that encodes which of the following extracellular matrix proteins?
Collagen
Entactin
Fibrillin
Fibronectin
Hereditary nephritis (Alport syndrome) reflects abnormal type IV collagen in the glomerular basement membrane. The syndrome is a proliferative and sclerosing glomerular disease, often accompanied by defects of the ear or the eyes, which is caused by a genetic abnormality in type IV collagen. Hematuria is present early in life in males with X-linked disease and in both sexes with autosomal recessive disease. Proteinuria, progressive renal failure, and hypertension develop later in the course of the disease. Virtually all men with the X-linked syndrome and both sexes with autosomal recessive disease develop end-stage renal disease by ages 40 to 50 years. Patients with Marfan syndrome have mutations in the fibrillin gene (choice C).Diagnosis: Hereditary nephritis, Alport syndrome
Kidney