|
Document Type |
: |
Thesis |
|
Document Title |
: |
The Evaluation of DiGeorge Syndrome Gene Deletion by Molecular Cytogenetic Applica-tions تقييم حذف مورث متلازمة دي جورج بتطبيق الوراثة الخلوية الجزيئية |
|
Subject |
: |
genetic diseasesinborm |
|
Document Language |
: |
English |
|
Abstract |
: |
DiGeorge Syndrome (DGS) is known as 22q11.2 deletion syndrome. It is a ge-netic disorder that is being recognized with increasing frequency with a documented incidence of approximately 1 in 4000 and is the most common human deletion syn-drome, typically present early in life and is rarely appearing in adult patients. Micro-deletion of chromosome 22q11.2 is one of the most clinically variable syndromes, with more than 180 features associated with the deletion. The syndrome is caused by genetic deletions (loss of a small part of the genetic material) found on one of the two 22nd chromosomes. Very rarely, patients with similar clinical features may have deletions on the chromosome 10. There is no genetic cure for 22q11.2 deletion syn-drome. Evaluations are recommended at regular intervals to monitor progress and as-sess changing needs; for example of some needs: patients with hypocalcaemia they will be supplemented with calcium and vitamin D and patients with congenital heart disease surgical should be done. In this study, the deletion of 22q11.2 was screened in 30 suspected DGS patients depending on their symptoms, using cytogenetic, FISH (Fluorescence in situ Hybridization) and Array-CGH (Comparative Genomic Hybridi-zation) techniques for each patient. The purpose of this study is to compare the effec-tiveness of using these techniques in detecting the deletion of chromosome 22q11.2. Out of 30 patients, only 1 patient was detected for the 22q11.2 deletion by cytoge-netic technique while other chromosomal aberrations were detected in three patients (48,XXXX / 46,XX,del(18)(p11.2)/ 47,XX,+18), 2 patients were detected for the 2q11.2 deletion by FISH and 8 patients were detected by array-CGH. From the number of patients that were detected to have the 22q11.2 deletion, array-CGH technique detects the highest number comparing to FISH and cytogenetic analysis. Array-CGH is a highly sensitive technique because it depends on the scanning of the whole genome in each patient; therefore any other genetic aberration such as any gain or loss can be detected. However, a cryptic chromosomal aberration uncovered by array-CGH can be confirmed back using cytogenetic G-banding technique. High – resolution banded chromosomes is require to detect the deletion, and therefore it is practically difficult to be achieved for all the patients. This technique may however be useful in case of misdiagnose given from the clinical variation of this Syndrome. In FISH, the probe used will enable detection of a specific region only and may not cover the entire DGS region. The limitation can be overcome to some extent by use of different probes to screen the entire gene. We, therefore conclude that array-CGH is a highly sensitive technique compare to cytogenetics and FISH in the diagnosis of DGS. |
|
Supervisor |
: |
Sahira Lary |
|
Thesis Type |
: |
Master Thesis |
|
Publishing Year |
: |
1434 AH
2013 AD |
|
Number Of Pages |
: |
94 |
|
Co-Supervisor |
: |
Mohammed Al qahtani |
|
Added Date |
: |
Thursday, September 11, 2014 |
|
Researchers
| عبير احمد باحمط | Bahmamat, Abeer Ahmed | Investigator | Master | |
|