The dystrophin gene

The human dystrophin gene (DMD) is located on
the short arm of the X chromosome in region 2,
band 1.1 (Xp21.1). Dystrophin is by far the largest
known gene in man, spanning 2.4 million base
pairs (2.4 Mb or 2400 kb) in 79 exons (2). The
large DMD transcript has 14 kb. The dystrophin
gene contains at least seven intragenic promoters.
The primary transcript is alternatively
spliced into a variety of different mRNAs that
encode smaller proteins expressed in other tissues
than muscle cells, especially in the central
nervous system.