Very low birth weight is a risk factor for secondary focal segmental glomerulosclerosis

Abstract

Background and objectives: Low birth weight (LBW), resulting from intrauterine growth retardation (IUGR) or prematurity, is a risk factor for adult hypertension and chronic kidney disease. LBW is associated with reduced nephron endowment and increased glomerular volume; however, the development of secondary focal segmental glomerulosclerosis (FSGS) has not been reported previously.

Design, setting, participants & measurements: The authors describe six patients with clinical and pathologic findings suggesting a secondary form of FSGS, in whom a history of prematurity and very LBW was obtained. No other known causes of secondary FSGS were identified.

Results: The cohort consisted of two women and four men with a mean age of 32 yr. Patients were born at 22 to 30 wk gestation with mean birth weight of 1054 g (range 450 to 1420 g). Mean 24-h urine protein was 3.3 g/d (range 1.3 to 6.0 g/d), mean creatinine clearance 89 cc/min (range 71 to 132 cc/min), mean creatinine 1.2 mg/dl (range 0.9 to 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.

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 glomerulomegaly and segmental occlusion of glomerular capillaries by matrix accumulation and hyalinosis in a perihilar distribution in all but one (b) (PAS stain; original magnification: ×40). Patient 6, the index case, is (e). (f) Ultrastructural examination of a glomerular capillary from Patient 4 demonstrates minimal foot process effacement (electron micrograph; original magnification: ×5000)