Alport syndrome

Alport syndrome is a hereditary disease characterized by progressive sensorineural hearing loss, renal disease and, at times, ocular lesions.

Clinical presentation

• hematuria

• sensorineural hearing loss: typically high frequency ²

• ocular abnormalities

  • anterior lenticonus which may result in cataracts

  • perimacular pigmentary changes

  • flecks around the fovea ²

• multiple leiomyomas ^1,2

  • esophagus

  • tracheobronchial tree

  • female genitalia

Pathology

Alport syndrome results from mutations in the type IV collagen genes COL4A3, COL4A4, and COL4A5 ⁸. Type IV collagen is found in the basement membrane of the glomerulus, the cochlea, and the eye.

Genetics

Mutations may be inherited in X-linked dominant (most common), autosomal recessive, or autosomal dominant patterns ^7,8. In its most common form, males are more severely affected, although females also demonstrate abnormalities ².

Associations

• midface hypoplasia ³

Radiographic features

Ultrasound

In the early stage the kidneys are normal in size and echotexture, but in advanced disease they may be atrophic and echogenic. In a patient presenting with new hematuria with an established familial diagnosis of Alport syndrome, the absence of mass or structural abnormality on urinary tract ultrasound is likely to represent Alport syndrome ⁹.

CT

Kidneys may be shrunken with delayed or non-excretion of contrast in advanced stages.

Multiple leiomyomas can be seen in the esophagus ⁵, tracheobronchial tree, or uterus.

MRI

MRI brain may show patchy/nodular lesions in gangliothalamic complexes, with reduced white matter myelination ⁴.

History and etymology

Named for Arthur Cecil Alport (1880-1959), an English physician.