Renal histopathology in Alagille's syndrome.

Various renal abnormalities have been reported in Alagille's syndrome (arteriohepatic dysplasia), usually as single case reports. The renal findings at autopsy of four patients with Alagille's syndrome, ranging in age from 4 1/2 months to 7 years, 2 of whom had evidence of renal dysfunction, are described and are compared with kidneys from patients with other cholestatic liver diseases of childhood. Two of the Alagille's patients had histologic findings suggestive of membranous nephropathy and special stains revealed accumulation of lipid in the glomerular and tubular basement membranes. Immunofluorescence of 1 revealed extensive accumulation of IgG and IgM. One patient had medullary cysts and mild interstitial fibrosis, and the fourth had a large subcapsular cyst and mild tubulointerstitial nephritis. All 4 cases, when examined with the electron microscope, revealed varying degrees of basement membrane thickening, splitting, and vacuolation with dense osmiophilic particles, most prominent in the patients with membranous nephropathy. These ultrastructural findings did not correlate with the degree of hyperlipidemia, but rather with the patient's age, and were also observed in other cholestatic diseases. The findings suggest that Alagille's syndrome is frequently associated with renal abnormalities, including lipid deposition, which may in some instances, lead to clinically significant renal impairment.