This is a mechanism module, not a specific disease. Disorder entries reference individual nodes via conforms_to (e.g., "nephrotic_podocyte_injury#Glomerular Filtration Barrier Breakdown"). The module defines the expected pathophysiology structure; conforming nodes in disorder files should include the corresponding podocyte cell type, biological processes, and causal edges, specialized to their etiologic context. Key disorder-specific substitutions: genetic forms substitute the mutated slit-diaphragm/cytoskeleton gene product (nephrin in NPHS1, podocin in NPHS2); minimal change disease and primary FSGS substitute a circulating permeability factor or immune mechanism as the trigger; secondary forms (diabetic nephropathy, lupus, membranous) substitute their specific glomerular insult while preserving podocyte injury as the central lesion.
Podocyte Injury
trigger
A circulating permeability factor, immune or toxic mechanism, or an inherited mutation in a slit-diaphragm or cytoskeletal protein (nephrin, podocin, or actin-regulating proteins) injures the glomerular podocyte. Across primary, genetic, and secondary nephrotic syndromes the initiating lesion converges on the podocyte and its actin cytoskeleton, the central target whose perturbation begins the pathway to filtration barrier failure.
Downstream
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Foot Process Effacement and Slit Diaphragm Disruption
Show evidence (2 references)
"Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by..."
Review evidence establishes podocyte injury as the central lesion and lists the converging triggers — circulating permeability factors and genetic defects in slit diaphragm, actin cytoskeleton, and foot process structure. Evidence source is OTHER because this is a pathogenesis review.
"it has become obvious that the podocyte is crucial in the pathogenesis of not only genetic but also of many acquired glomerulopathies such as focal segmental glomerulosclerosis, membranous glomerulopathy and diabetic nephropathy."
Establishes that the podocyte is the conserved central target across genetic and acquired glomerulopathies, supporting podocyte injury as the shared trigger node. Evidence source is OTHER because this is a review.
Glomerular Filtration Barrier Breakdown
central effector
Loss of foot process and slit diaphragm integrity, together with podocyte, glomerular basement membrane, and endothelial dysfunction, breaks down the size- and charge-selective glomerular filtration barrier. The barrier can no longer restrain plasma proteins, so albumin and larger proteins pass into the urinary space. This is the central effector step that converts a podocyte structural lesion into pathological filtration.
Downstream
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Massive Proteinuria with Podocyte Loss
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"any glomerular insult may alter the glomerular filtration barrier, which in turn is composed by the podocyte, the glomerular basement membrane, and the capillary endothelial cell."
States that glomerular insults alter the filtration barrier and defines its podocyte/GBM/endothelial composition, supporting barrier breakdown as the central effector. Evidence source is OTHER because this is a review.
"Disruption of the glomerular filter composed of the glomerular endothelium, glomerular basement membrane and podocytes, results in albuminuria."
Directly connects disruption of the glomerular filter to albuminuria, i.e., failure of the filtration barrier producing protein loss. Evidence source is OTHER because this is a methods paper reviewing the glomerular filter.
Massive Proteinuria with Podocyte Loss
effector
Sustained barrier failure produces massive proteinuria. Because podocytes are terminally differentiated and do not normally divide, ongoing injury leads to their detachment from the glomerular basement membrane and progressive podocyte loss. Once podocyte loss exceeds a critical threshold in a glomerulus, glomerulosclerosis develops and the glomerulus is progressively obliterated, establishing chronic, often progressive disease.
Show evidence (2 references)
"As the insult progresses, podocytes start to detach from the glomerular basement membrane. When the podocyte loss is over 40% in a glomerulus, glomerulosclerosis develops, and obliteration of the glomerulus is the rule. In clinical grounds, this phenomenon is diagnosed mainly by proteinuria and..."
Directly links progressive podocyte detachment and loss to glomerulosclerosis and proteinuria, the effector step of the module. Evidence source is OTHER because this is a review.
"Angptl3 knockout effectively delayed glomerulosclerosis formation by attenuating podocyte loss through rescuing podocytes from detachment and apoptosis."
Murine adriamycin nephropathy data show that reducing podocyte detachment and loss delays glomerulosclerosis, confirming the causal podocyte-loss to glomerulosclerosis link. Evidence source is MODEL_ORGANISM (mouse model).
Nephrotic Syndrome
consequence
The convergent clinical consequence of glomerular filtration barrier failure is nephrotic syndrome: nephrotic-range proteinuria with hypoalbuminemia, peripheral edema, and hyperlipidemia. Whatever the initiating podocyte insult — minimal change disease, focal segmental glomerulosclerosis, genetic podocyte-gene disorders, or secondary causes — the disease-defining phenotype is shared, with complications including thrombosis and infection.
Show evidence (2 references)
"Nephrotic syndrome is characterized by edema, proteinuria, hypoalbuminemia, and hyperlipidemia."
Defines the convergent clinical phenotype of nephrotic syndrome, the consequence node of the module. Evidence source is OTHER because this is a review.
"Most cases of NS are considered idiopathic or primary; membranous nephropathy and focal segmental glomerulosclerosis are the most common histologic subtypes of primary NS in adults."
Confirms that distinct primary glomerulopathies converge on the shared nephrotic syndrome phenotype, supporting it as the conserved consequence. Evidence source is OTHER because this is a review.