A four-year-old child is diagnosed with Duchennemuscular dystrophy, an X-linked recessive disorder. Genetic analysis shows that the patient's gene for the muscle protein dystrophin contains a mutation in its promoter region. What would be the most likely effect of this mutation?

Initiation of dystrophin transcription will be deficient Transcription of DNA gene into RNA is a 4 step process involving: Initiation, Elongation, Termination and Posttranscriptional modification (capping, splicing, addition of poly-A tail) The 'promoter' region of DNA is responsible for initiation of the RNA transcription, hence any mutation in this region is going to effect the initiation process of mRNA. (Transcription is an impoant topic and a detailed study from standard textbooks is a must; an easy and good explanation is given in Lippincott)