Clinical Presentation and Triad of Symptoms
This pathology belongs to a group of heterogeneous hereditary and familial disorders with primary damage to the renal glomeruli. The most well-known and frequent form of this group is Alport syndrome.
The classic clinical presentation consists of three main manifestations:
- Nephritis — the leading renal syndrome.
- Deafness or pronounced sensorineural hearing loss.
- Eye disorders, including lens dislocation (lenticonus), corneal dystrophy, and posterior cataracts.
Epidemiological data show gender differences: males suffer significantly more severely and more frequently than females, and end-stage renal disease develops earlier in them. Gross or microscopic hematuria, red blood cell casts, and proteinuria prevail in the urinary system, while nephrotic syndrome is less common.
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 alterations in the renal parenchyma.
On light microscopy, renal glomeruli are invariably involved, typically presenting as mesangioproliferative glomerulonephritis. A characteristic morphological feature is «foamy cells» — glomerular and tubular epithelial cells that accumulate neutral fats and mucopolysaccharides.
Over time, the pathological process steadily progresses. Pathologists record:
- development of nephrosclerosis;
- marked narrowing of vascular lumens;
- tubular atrophy;
- progression of interstitial fibrosis.
Electron Microscopy in Hereditary Nephritis
Electron microscopy plays a key role in diagnosis, revealing the most specific changes affecting basement membranes:
- Irregular areas of pathological thickening and thinning of the GBM.
- Characteristic pronounced splitting and lamination of the lamina densa.
- Similar destructive changes are also found in the tubular basement membrane.
This ultrastructural picture has crucial differential diagnostic value, being most specific precisely for Alport syndrome.