Rare familial nephropathy due to abnormalities in type IV collagen.
May be inherited in 1 of 4 patterns: X-linked, autosomal recessive, autosomal dominant or autosomal digenic.
Associated with considerable clinical variability of age of onset of chronic renal failure. Frequently associated with sensorineural hearing loss.
Female carriers of X-linked mutations have a significant lifetime risk of developing hypertension and renal disease.
Strong genotype-phenotype correlations in X-linked Alport syndrome have been described in male patients.
Monitoring and treatment of renal disease is the main treatment.
Alport syndrome is an inherited disease of the glomerular basement membrane caused by abnormalities in type IV collagen. It is associated with sensorineural hearing loss, lenticonus (bulging of the lens capsule and the underlying cortex) and retinal abnormalities, as these tissues are additional sites of expression of type IV collagen. The classic thickening and lamellation of the glomerular basement produces a progressive hematuric nephritis that progresses to chronic renal failure in all males with the X-linked form of the disease.
History and exam
Key diagnostic factors
- gross hematuria
- hearing impairment
Other diagnostic factors
- peripheral edema
- foamy-appearing urine
- visual disturbance
- learning disability
- cough or recurrent bronchitis
- growth retardation
- irregular firm central pelvic mass
- family history of Alport syndrome
- family history of thin basement membrane nephropathy
- family history of microscopic hematuria
- microscopic hematuria
1st investigations to order
- metabolic panel
- fasting lipid panel
- serum intact PTH
- renal ultrasound
- renal biopsy
Investigations to consider
- molecular genetic testing
- skin biopsy
- MYH9 disorders (Epstein syndrome and Fechtner syndrome)
- Branchio-oto-renal syndrome
- Thin basement membrane nephropathy
- Alport syndrome: a unified classification of genetic disorders of collagen IV α345: a position paper of the Alport Syndrome Classification Working Group
- Clinical practice recommendations for the treatment of Alport syndrome
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