The nail-patella syndrome (OMIM #161200) or hereditary osteo-onychodysplasia (HOOD syndrome) is a rare autosomal dominant disorder caused by LMX1B mutations, characterized by limb and pelvic skeletal abnormalities (eg, hypoplastic or absent patella, elbow dysplasia, and iliac horns), dystrophic nails and distal digital abnormalities, and kidney disease, with an estimated incidence of 1/50,000. Renal involvement is the major determinant of prognosis. Besides kidney disease and skeletal and nail abnormalities, other findings may include sensorineural hearing loss, glaucoma, gastrointestinal involvement, and vasomotor dysfunction.

Bile nephrosis occurs in patients with liver failure, and is associated with a clinical history of jaundice and elevated total bilirubin levels, usually greater than 20 mg/dL. Patients can present with acute kidney injury (AKI) or chronic kidney disease.

Patients with light chain cast nephropathy are often middle-aged or older and present with acute kidney injury. They typically have overt multiple myeloma at the time of diagnosis. Conversely, about half of patients with multiple myeloma and kidney disease have light chain cast nephropathy. There is associated nephrotic-range proteinuria, composed largely of light chains. The lesser albuminuria can manifest as low-level proteinuria by dipstick analysis. Patients may also have additional AL amyloid or monoclonal immunoglobulin deposition disease.

The Columbia classification of focal segmental glomerulosclerosis (FSGS) describes 5 variants, of which the cellular variant is the rarest. This variant is more common in children than in adults, and typically presents with nephrotic-range proteinuria. The cellular variant can be diagnosed after excluding collapsing and tip variants, when there is endocapillary hypercellularity involving at least 25% of the tuft of at least one glomerulus, without immune complexes, and typically with extensive foot process effacement.

Glomerulonephritis with dominant C3, a form of C3 glomerulopathy, typically presents with subnephrotic proteinuria and hematuria. Although a minority of patients may present with nephrotic syndrome, about half present with hypertension and impaired glomerular filtration rate. Up to 15% progress to end-stage renal disease. C3 glomerulopathy is rare with a typical age of onset of 30 years (range, 7-70 years).

Antibiotic therapy has decreased the incidence of glomerulonephritis related to subacute bacterial endocarditis (SBE). Kidney involvement may be the initial manifestation of SBE in about 20% of patients. Hematuria and mild proteinuria are commonly present. Hypertension and nephrotic syndrome are rare. Serum complement levels may be low. Gross hematuria may be present in patients with renal infarctions related to embolic events. The degree of GFR loss correlates with the severity of glomerulonephritis; diffuse glomerulonephritis causes moderate GFR loss, and necrotizing glomerulonephritis with crescents can cause a rapid GFR decline.

Antibiotic therapy has decreased the incidence of glomerulonephritis related to subacute bacterial endocarditis (SBE). Kidney involvement may be the initial manifestation of SBE in about 20% of patients. Hematuria and mild proteinuria are commonly present. Hypertension and nephrotic syndrome are rare. Serum complement levels may be low. Gross hematuria may be present in patients with renal infarctions related to embolic events. The degree of GFR loss correlates with the severity of glomerulonephritis; diffuse glomerulonephritis causes moderate GFR loss, and necrotizing glomerulonephritis with crescents can cause a rapid GFR decline.