The titin gene (TTN) produces a very large muscle protein called titin, which is found in the heart and skeletal muscles. A mutation of this gene can lead to the following conditions: Centronuclear Myopathy and Limb-Girdle Muscular Dystrophy type 2J (LGMD2J)

Severe weakness in skeletal muscles, delayed motor skills, wheelchair use, atrophy, high palate, scoliosis and respiratory failure can be seen.