• INCLUSION CRITERIA:

All patients with idiopathic FSGS and idiopathic and HIV-associated collapsing glomerulopathy, and kidney donors are eligible.

AFRICAN-AMERICANS WITH FSGS:

Renal biopsy showing FSGS or collapsing glomerulopathy, including HIV-associated collapsing glomerulopathy (HIV-associated nephropathy).

We will include adult and pediatric patients.

OTHER PATIENTS WITH FSGS:

Renal biopsy showing FSGSor collapsing glomerulopathy, including HIV-associated collapsing glomerulopathy (HIV-associated nephropathy).

We will include adult and pediatric patients.

AFRICAN AMERICANS WITH HIV AND WITHOUT KIDNEY DISEASE (CONTROLS):

We will include adult patients who have had serologically confirmed HIV-1 infection for at least 8 years and lack clinical renal disease, as evidenced by normal creatinine and urine protein/creatinine ratio less than 0.5 or 24 hour urine protein excretion less than 500 mg/d.

AFRICAN AMERICAN BLOOD DONORS (CONTROLS):

We will include adults only.

HEALTHY CAUCASIAN CONTROLS (CONTROLS):

These samples represent DNA already obtained.

RELATIVES OF PATIENTS WITH FSGS:

In selected families (in which a patient has been found to have a mutation in a FSGS risk gene whose pathologic role has not been established), we will obtain individual histories of renal disease (hematuria, proteinuria, hypertension,nehrolithiasis) and will measure serum creatinine and urine protein excretion. We will include adults with and without renal disease and children with renal disease. We will evaluate children less than 18 years by obtaining a urine sample; if urinalysis and urine protein excretion are normal, we will not a request a blood sample.

KIDNEY DONORS:

We will include NIH kidney donors only. We will obtain individual histories that provide information as to age, sex, race, surgical and medical histories, and family history. Dr. Cho, as part of another protocol, will measure urinary albumin and kidney size (which by comparison with radiologic studies done at the time of kidney donation will allow determination of kidney hypertrophy following donation). Our purpose is to examine whether particular genetic variants, including those in MYH9, influence the ability of the kidney to undergo hypertrophy following renal donation or the propensity to manifest albuminuria as a sign of glomerular stress. These findings have the potential to extend our understanding of the biology of MYH9 and might have clinical relevance for selecting kidney donors.

EXCLUSION CRITERIA:

AFRICAN-AMERICANS WITH FSGS:

We will exclude patients with hyperfiltration FSGS (reduced renal mass, chronic interstitial nephritis, sickle cell anemia, obesity with BMI greater than 40 kg/m(2)).

OTHER PATIENTS WITH FSGS:

No patients with hyperfiltration FSGS (reduced renal mass, chronic interstitial nephritis, sickle cell anemia, obesity with BMI greater than 40 kg/m(2)).

AFRICAN AMERICAN BLOOD DONORS (CONTROLS):

HIV-1 infection.

Renal disease.

HEALTHY CAUCASIAN CONTROLS (CONTROLS):

Patients will not be recruited as part of the present study.