See the first aid entry on Tuberous sclerosis. It is associated with increased incidence of subependymal giant cell astrocytoma and many other conditions.

Tuberous sclerosis = "ash-leaf spots" = oval-shaped areas pale areas on skin. often d/t hamartomas

This pretty much answers 3-4 of the mnemonic for tuberous sclerosis: "HAMARTOMASS"

H-amartomas in CNS and skin/ A-ngiofibromas/ M-itral regurgitation/ A-sh leaf spots (hypopigmented macule) / R-cardiac Rhabdomyoma/ T-uberous Sclerosis/ O-autosomal dOminant/ M-mental retardation / A-renal Angiomyolipoma/ S-eizures/ S-hagreen patches /