Prader-Willi syndrome (PWS) is a neurobehavioral disorder characterized mainly by neonatal hypotonia, dysmorphic features, hypogonadism, mental retardation and behavioral problems. The PWS has not been associated with renal complications. We report the case of an infant with Prader-Willi syndrome due to loss of the paternal copy of chromosome 15q11.2-13, who presented with severe proteinuria and microscopic hematuria. Renal biopsy revealed mesangioproliferative glomerulonephritis (MPGN). The early onset of the primary MPGN in this infant make us consider a possible association between the deficiency of the paternally expressed genes from the 15q11-q13 region and the renal disease.