Employing Real Time PCR for the Diagnosis of Huntington Disease

Background: Huntington disease (HD) is a dominantly inherited, neurodegenerative disease characterized by choreiform movement disturbances and dementia. The onset age of this disease is varied but usually is between the ages 40-50. Huntington's disease is caused by a triplet-repeat expansion in the IT15 gene (also known as huntingtin or HD) which is located on chromosome 4p3.1. Since many clinical picture of HD are indistinguishable from other distinct genetic disorders molecular test such as PCR is the only way to confirm the disease. The aim of this study was to introduce a new and fast technique for the diagnosis of Huntington disease. Materials and Methods: Blood specimens were collected from individuals suspected for Huntington disease and also people with no symptoms and family history of this disease. DNAs were extracted according to standard protocol. Using conventional PCR, patient positive for Huntington disease were diagnosed. Then employing real time PCR on the basis of difference between melting temperature (Tm) a new and fast diagnostic method was introduced. Results: Among 29 patients suspected to be HD only 8 HD patients were confirmed using PCR and real time PCR. The numbers of CAG repeat were between 42-50 and melting temperatures were between 89-92. Conclusion: The concept of using melting temperature in real time PCR protocol presented in here could be employed for the rapid diagnosis of the diseases caused by the increased in triple repeat sequences. It is fast, robust and has the potential use for the prenatal diagnosis.