Where measured, an increased glomerular volume significantly correlated with low nephron number and LBW (7,8). clearance 89 cc/min (range 71 to 132 cc/min), mean creatinine 1.2 mg/dl (range 0.9 to 1 1.5 mg/dl), and mean serum albumin 4.1 g/dl (range 3.4 to 4.8 g/dl). No patient had full nephrotic syndrome. Renal biopsy revealed FSGS involving a minority (mean 8.8%) of glomeruli, with a predominance of perihilar lesions of sclerosis (five of six patients), glomerulomegaly (all six patients), and only mild foot process effacement (mean 32%), all features typical of postadaptive FSGS. Conclusions: Our findings support that very LBW and prematurity promote the development of secondary FSGS. Because birth history is often not obtained by adult nephrologists, this risk factor is likely to be underrecognized. The index case is a 15-yr-old Caucasian male who was found to have mild proteinuria during routine urinary screening. His birth was complicated by prematurity (23 wk gestational age) and a very low birth weight (1.40 kg). He had had numerous perinatal problems associated with prematurity including respiratory complications, intracranial hemorrhage, necrotizing enterocolitis, bowel obstruction, sepsis, and retinopathy of prematurity. There was no history of hematuria, urinary reflux, renal insufficiency, recent fevers, hearing loss, or familial renal disease. He was taking no medications. The patient was followed for several weeks and was found to have persistent, mild proteinuria not associated with exercise or posture (nonorthostatic). Physical examination revealed a height of 172 cm and a weight of 75 kg (body mass index = 25.4 kg/m2), BP of 127/79 mmHg (90th percentile), and no edema. Renal ultrasound revealed normal-appearing kidneys measuring 10.5 cm and 9.6 cm in length. Laboratory examination showed a hematocrit of 50% (normal = 37% to 45%), white blood cell count 7.8 109/L (normal = 4.5 to 13.5 109/L) with normal differential, platelet count 221 109/L (normal 150 to 450 109/L), blood urea nitrogen 15 mg/dl (5.8 mmol/L) (normal = 7 to 18 mg/dl [2.5 to 6.4 mmol/L]), creatinine clearance 100 cc/min, serum creatinine 0.9 mg/dl (75.6 mol/L), total serum protein 7.3 AP20187 g/dl (73 g/L) (normal 6 to 8 8.2 g/dl [60 to 82 g/L]), and serum albumin 4.4 g/dl (44 g/L) (normal 3.4 to 5.0 g/dl [34 to 50 g/L]). AP20187 Serum electrolytes, including sodium, potassium, bicarbonate, chloride, and calcium, were normal. The following serologies were negative: anti-nuclear antibody, antidouble-stranded DNA antibody, hepatitis B surface antigen, and hepatitis C antibody. Serum complement levels, including C3 and C4, were within normal range. Urinalysis revealed a specific gravity of 1 1.030, pH 5, and protein > 300 mg/dl, with negative glucose, heme and leukocyte esterase. The 24-h urinary protein was 1.34 g. Microscopic examination of the urine revealed zero to five white blood cells AP20187 per high-power field, no red blood cells, and no hyaline or granular casts. A renal biopsy was performed to determine the cause of persistent subnephrotic proteinuria. Light microscopic examination showed one core of tissue consisting of renal cortex and a small portion of outer medulla. There were 8 glomeruli, none of which were globally sclerotic. The glomeruli appeared hypertrophied but normocellular, with patent capillaries Rabbit Polyclonal to SCARF2 and glomerular basement membranes of normal thickness. No immune-type fuchsinophilic deposits were identified with the trichrome stain. There was patchy, mild tubular atrophy and interstitial fibrosis involving approximately 20% of the cortex, with sparse interstitial infiltrates confined to those areas. Nonatrophic tubules appeared hypertrophied. There was mild, focal arteriolosclerosis; interlobular arteries appeared unremarkable. One of the four glomeruli sampled for immunofluorescence showed 2+ segmental tuft staining for IgM and C3. There was negative staining for IgG, IgA, C1, fibrinogen, and kappa and lambda light chains. The cryostat sections were stained with PAS; light microscopic examination disclosed one glomerulus containing a discrete segmental lesion of sclerosis in the perihilar location (Figure 1e). == Figure 1. == Renal biopsy findings. (a) Normal sized control glomerulus (hematoxylin and eosin stain; original Magnification: 40). (b-e) Representative glomeruli from Patients 1, 2, 5, and 6 demonstrate.