Glomerulonephritis is a disease which affect the kidneys. Occasionally these diseases can
progress to a loss of kidney function in some patients. Glomerulosclerosis or focal segmental
glomerulosclerosis (FSGS) is one form of glomerulonephritis.
The cause of FSGS is unknown and often occurs on its own (idiopathic), or it can be
associated with HIV (Human Immunodeficiency Virus). FSGS occurs more commonly among black
patients than Caucasian or Hispanic patients. Researchers believe that environmental factors
may interact with genetic mutations to cause FSGS, at least in some patients.
This study will attempt to identify genetic factors associated with the development of FSGS.
The study population will be made up of 600 total subjects divided into 3 groups. Group one
will be 200 African-Americans with FSGS. Group two will be 200 African-Americans with HIV but
without FSGS. Group three will be 200 non-African-Americans with FSGS.
Study participation requires that researchers obtain 20 ml (2 tubes of blood). The genetic
material (DNA) will be prepared from the white blood cells and analyzed. The results of each
group will be compared with the results from the other groups to determine if one or more
genes predisposes to FSGS. In the long run, studies that demonstrate a genetic basis for FSGS
may help us identify patients earlier and may lead to improved therapies....
Focal segmental glomerulosclerosis (FSGS) and a related condition, collapsing glomerulopathy,
are chronic renal diseases affecting the glomerular podocytes. Currently, over thirteen
genetic mutations are associated with FSGS. We are interested in expanding our understanding
of these and other genes that may cause FSGS and collapsing glomerulopathy. We will study
individuals with affected family members. We will also study sporadic cases; the rationale
for studying this population is that FSGS and collapsing glomerulopathy are significantly
more common among individuals of African descent. The latter observation suggests that
particular FSGS-susceptibility alleles may be more common among African Americans. In the
present study, we are addressing the hypothesis that genetic variation contributes to the
pathogenesis of idiopathic FSGS and collapsing glomerulopathy, both idiopathic and HIV
We are studying the following groups:
1. African-Americans with idiopathic or HIV-associated collapsing glomerulopathy. We will
exclude post-adaptive FSGS, associated with glomerular hyperfiltration, and medication
2. Other patients with idiopathic FSGS<TAB>
3. African Americans with HIV and without kidney disease (hyper-normal controls)
4. African descent controls (controls).<TAB>
5. Healthy European and Asian descent controls (controls).<TAB>
6. Relatives of patients with familial FSGS
7. Kidney donors
We are taking three methodologic approaches. First, we are examining known FSGS risk genes or
candidate genes, looking for disease-causing mutations and for disease-susceptibility
haplotypes. Second, we have undertaken a genome scan, in the African descent population. We
may also undertake a whole genome scan in European and Asian descent. Evidence of linkage
disequilibrium among these markers will be sought between patients with and without FSGS.
Third, when we identify families with multiple affected individuals and which lack known
genetic mutations affecting FSGS genes, we will pursue positional cloning.
- INCLUSION AND EXCLUSION CRITERIA, BY GROUP:
1. African-descent with FSGS: renal biopsy showing FSGS or collapsing
glomerulopathy, including HIV-associated collapsing glomerulopathy
(HIV-associated nephropathy). We will include adult and pediatric patients. We
will exclude patients with hyperfiltration FSGS.
2. Other patients with FSGS (similar inclusion and exclusion criteria as in group
3. African descent 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 <0.5 or 24 hour urine protein excretion <500 mg/d.
4. African descent (controls). We will include adults only. Exclusions will include
HIV-1 infection, cardiovascular disease, and renal disease.
5. European and Asian descent (controls). These samples represent DNA already
obtained by Dr. Winkler s group under IRB approved protocols and these patients
will not be recruited as part of the present study.<TAB>
6. Relatives of patients with FSGS. In selected families (in which a patient has
been found to have a mutation in an FSGS risk gene whose pathologic role has not
been established), we will obtain individual histories of renal disease
(hematuria, proteinuria, hypertension, nephrolithiasis) 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 <18
years by obtaining a urine sample; if urinalysis and urine protein excretion are
normal, we will not request a blood sample unless blood is being obtained for a
7. 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. 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.
8. Tamil population. We will recruit from a Tamil population. A Tamil will be
defined as anyone that identifies themselves, their parents and their
grandparents as Tamilian. We will ask these patients about their family history.
We will exclude subjects under 18 and multiple subjects within the same family.
We will draw blood for genetic testing. Our purpose is to determine whether
particular genetic variants, including those in MYH9, are prevalent in a Tamilian
population. If prevalence is indicated, we hope to study how these variants
influence the progression of kidney disease in this population.
9. Women who are pregnant will be excluded from participating in the apheresis
component of this protocol.