Kelch Repeat And BTB Domain Containing Protein 13 (KBTBD13)

Kelch is a 50-residue motif, named after the Drosophila mutant in which it was first identified. This sequence motif represents one beta-sheet blade, and several of these repeats can associate to form a beta-propeller. For instance, the motif appears 6 times in Drosophila egg-chamber regulatory protein, creating a 6-bladed beta-propeller. The motif is also found in mouse protein MIPP and in a number of poxviruses.

Defects in KBTBD13 are the cause of nemaline myopathy type 6 (NEM6). A form of nemaline myopathy characterized by childhood onset of slowly progressive proximal muscle weakness, exercise intolerance, and slow movements with stiff muscles. Patients are unable to run or correct themselves from falling over.