الفهرس 
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Abstract
Congenital heart diseases are the most common of all birth defects and are the leading cause of mortality in the first year of life with a prevalence of 7-10 per 1000 live birth. CHD may occur as an isolated malformation or may be part of a syndrome. One of the most common syndromes associated with CHDs is the 22q11.2 DS. It is the most frequent interstitial deletion found in man with an incidence of about 1 in 4000 live birth.
The various conditions associated with 22q11.2DS include DiGeorge anomaly, velocardiofacial syndrome, conotruncal anomaly face syndrome, isolated conotruncal heart defects, Cayler cardiofacial syndrome and other syndromes.
The vast majority of patients with 22q11.2 DS (90%) share a deletion of approximately 3Mb. The deletion is not detectable by classic cytogenetic techniques. In order to detect the deletion, other techniques, such as FISH or microarray, must be used. FISH is the gold standard method in this domain.
The aim of the present work was to detect 22q11.2 microdeletion among patients with conotruncal heart defects. The parents of patients in whom 22q11.2 deletion was confirmed, were studied genetically as well. This would allow accurate diagnosis, more effective management, proper genetic counseling and ultimately prenatal diagnosis in affected families.
The study was carried out on 22 patients with conotruncal heart defects, diagnosed by echocardiography. All cases were subjected to careful history taking with pedigree construction, complete clinical examination, and cytogenetic analysis using G-banding technique. Patients with normal karyotype were subjected to FISH technique using TUPLE1 probe to detect 22q11.2 microdeletion. Lastly patients and their families were offered proper genetic counseling.
Examination of the studied cases revealed growth retardation in 6 patients (27.3%) and delayed milestones in 2 patients (9.1%) with mild dysmorphic features in 19 patients.
The types of conotruncal heart defects among the studied patients by echocardiography were TOF in 19 patients, DORV with PS in three patients and DORV without PS in five patients. Cytogenetic examination revealed normal karyotype in the studied patients.
FISH study revealed that two patients (9.1%) had 22q11.2 microdeletion, one of them was mosaic. The remaining 20 patients (90.9%) had normal chromosome 22. FISH analysis was offered to the parents of the two patients with 22q11.2 DS and revealed normal chromosome 22.
Dolicocephaly, minor ear anomalies, long face, slanting palpebral fissure, long philtrum and ocular hypertelorism were more frequently detected among 22q11.2 DS patients. The poor clinical outcome together with severe growth retardation ending with early demise observed in the patient showing non mosaic 22q11.2 microldeletion, was evident compared to the second patient with normal growth percentiles and better clinical outcome having mosaic microdeletion.