Danon disease

A genetic disorder characterized by heart problems, mental retardation and muscle weakness that affects males who usually die of cardiac arrhythmia or heart failure at around the age of 30. The disease is due to a deficiency of LAMP-2 (which stands for lysosome-associated membrane protein 2.) LAMP-2 is a glycoprotein molecule (a molecule made up of carbohydrate + protein) that is normally located on the membrane surrounding the lysosome (a packet of powerful corrosive enzymes that degrade "garbage" within cells). The gene for LAMP-2 is on the X chromosome which is why Danon disease selectively strikes boys who only have one X chromosome and spares girls who have two X chromosomes and so have a spare X to protect them. Heart transplantation is the only curative treatment at this moment for the fatal cardiac component of Danon disease. Danon disease is named for Dr. M.J. Danon who (together with colleagues) originally described it 1981 as "lysosomal glycogen storage disease with normal acid maltase."