Alport syndrome

Clinical presentation and symptom triad

This pathology belongs to a group of heterogeneous hereditary and familial disorders with primary injury to the renal glomeruli. The best-known and most common form of this group is Alport syndrome.

The classical clinical picture consists of three main manifestations:

1. Nephritis — the leading renal syndrome.
2. Deafness or pronounced hearing loss.
3. Eye diseases, among which lens dislocation, corneal dystrophy, and posterior cataract are found.

Epidemiological data show gender differences: men are affected significantly more severely and more frequently than women, and end-stage renal disease develops earlier in them. Gross or microscopic hematuria, red blood cell casts, and proteinuria predominate in the urinary system, while nephrotic syndrome is less commonly observed.

Pathogenesis and histological changes

The underlying cause of the disease is a primary defect in the synthesis of the glomerular basement membrane (GBM). This leads to structural changes in the renal tissue.

On light microscopy, the renal glomeruli are invariably affected, usually in the form of mesangioproliferative glomerulonephritis. A characteristic morphological feature is "foam cells" — glomerular and tubular epithelial cells that accumulate neutral fat and mucopolysaccharides.

Over time, the pathological process steadily progresses. Morphologists record:

• development of nephrosclerosis;
• pronounced narrowing of vascular lumens;
• tubular atrophy;
• proliferation of interstitial fibrosis.

Electron microscopy in hereditary nephritis

Electron microscopy plays a key role in diagnosis and reveals the most specific changes affecting the basement membranes:

• Irregularly shaped areas of pathological thickening and thinning of the GBM.
• Characteristic marked splitting and lamination of the lamina densa.
• Similar destructive changes are also found in the tubular basement membrane.

This ultrastructural picture is of paramount differential diagnostic significance, being the most specific for Alport syndrome.

Class and exam questions

What else to study on this topic

• Pathogenetic mechanisms of impaired glomerular basement membrane synthesis
• Differential diagnosis of mesangioproliferative glomerulonephritis in hereditary nephritis
• Ultrastructural features of tubular basement membrane involvement
• Mechanisms of formation and composition of "foam cells" in glomeruli and tubules
• Morphogenesis of interstitial fibrosis and nephrosclerosis in the progression of Alport syndrome

Other topics in the section "Diseases of the Kidneys and Urinary Tract"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.