Prognosis
For a male with X-linked Alport syndrome (XLAS), the disease follows a consistent but variable course, partly influenced by the COL4A5 genotype. At present the effect of any intervention prior to the development of end-stage kidney disease, including ACE inhibition, requires further prospective study in different genotype groups but current studies support a significant reduction in rate of progression following early intervention. Microscopic haematuria with episodic gross haematuria develops from an early age. Proteinuria then develops, which is a prelude to the development of hypertension and progressive renal failure. All males will eventually develop chronic kidney disease. The rate of progression to chronic kidney disease is mutation dependent in XLAS. Over 90% will develop chronic kidney disease before aged 30 years if they have a loss-of-function mutation in COL4A5.[4] In women with XLAS 12% may develop chronic kidney disease before aged 40 years; significant hearing loss may also develop in 10%. In autosomal forms of Alport syndrome, the natural history of the disease is less well characterised. In one series of 40 individuals with autosomal-recessive Alport syndrome, the median age was 31 years and the median age at end-stage renal disease (ESRD) was 22.5 years (range 10 to 38 years). A third of adults were found to have normal renal function.[61] Equal numbers were due to mutations in COL4A3 and COL4A4. The presence of at least one loss-of-function allele predicted an earlier onset of ESRD. Once chronic kidney disease has developed, patients with all types of Alport syndrome can be offered renal replacement therapy.[48] Hearing loss is irreversible and does not improve with renal transplant.[3]
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