Alport Syndrome (Collagen IV-Related Nephropathies)

Background and History: 

Alport syndrome was first reported perhaps as early as 1875, but the significance of the association of lethal renal disease and deafness as a familial disease was recognized by AC Alport in 1927 and his name became attached.  It is a common disorder and a member of a group of diseases known as collagen IV-related nephropathies. 

Clinical Correlations: 

This is a progressive disorder involving primarily three organs: kidney, eye, and inner ear.  The kidney becomes progressively damaged leading to eventual failure manifest by red blood cells in the urine.  Hearing loss begins in childhood resulting in deafness in many individuals although some adults retain some hearing.  High frequency loss is the earliest sign and can be detected in young children.  The lens and retina are often normal in childhood but cataracts and a characteristic deformity (lenticonus) are seen as the disease progresses. There is a tendency for cells on the surface of the cornea to spontaneously detach causing painful scratches that are slow to heal. The retina has a characteristic 'speckled' appearance although this has little impact on vision.

In general, males are more severely affected but even in X-linked disease carrier females can have symptoms. 

Genetics: 

Alport syndrome is not a single disease as evidenced by the fact that there are at least three patterns of inheritance: X-linked in which males are primarily involved, autosomal recessive, and autosomal dominant.  However, all affected individuals have a defect in a component of connective (fibrous) tissue that is an important constituent of tissue membranes.  The risk of recurrence, of course, depends upon the pattern of inheritance.

Diagnosis and Prognosis: 

The diagnosis is based on the association of kidney disease, ocular findings, and deafness.  Mutations in the connective tissue genes provide confirmation but are not always present.  Kidney failure is the most serious threat to longevity and a kidney transplant may be required.  Cataract surgery may also be required if lens abnormalities interfere with light reaching the retina.

Additional Information