Detection of Intragene Deletion and Duplication Sequences

                         Capillary gel electrophoresis has been applied to the analysis of PCR products in the detection of small gene deletions in several genetic diseases. 

                          Examples of this application include the detection of over 98% of deletions occurring on the dystrophin gene for the diagnosis of Duchenne muscular dystrophy; an 8-bp deletion in exon 3 of the P450c21B gene in individuals affected by 21-hydroxylase deficiency, a recessively inherited disease, and the ΔF508 mutation, a 3-bp deletion in the gene CFTR that is the most frequently mutation found in individuals affected with cystic fibrosis. 

                            Another example is detection of the internal tandem duplication (ITD) in the juxtamembrane domain-coding sequence of the FLT3 gene in acute leukemias. The mutation of this receptor is important in acute myelogenous and lympho blastic leukemias because patients with this mutation generally have a poorer prognosis for survival than patients without it.