Dopa - responsive dystonia is a disorder that involves involuntary muscle contractions, tremors, and other uncontrolled movements (dystonia) in humans. One of the causes of the disorder is Tyrosine hydroxylase (TH) deficiency. Recently, it was determined that many cases of the disease are NOT caused by mutations in the exon sequence. Instead, these individuals are unable to transcribe the gene when needed due to mutations unrelated to the exon segments. This is likely caused by
a. Mutations associated with spliceosome formation.
b. Mutations in the Shine - Delgarno sequence
c. Mutations in the gene's response element.
d. Mutations in the gene's silencer sequence
e. Mutations associated with the translational start codon.