In our case, the onset of the cysts was uncertain, but we assume that they appeared in infancy at the latest because our patient had already developed polycystic kidney disease by the initial MRI. Since no clinical markers have been identified in TSC2/PKD1 contiguous gene syndrome, clinicians should consider the possibility of this syndrome when they detect early-onset polycystic kidney lesions in patients with typical manifestations of TSC. The gene discussed is PKD1; the disease is tuberous sclerosis.