ABSTRACT
To evaluate the cytogenetic findings among Saudi referred for suspected chromosomal anomalies that caused a variety of clinical disorders. Secondly, to estimate the frequency of chromosomal abnormalities in these patients and to compare our results with those reported in Saudi Arabia and elsewhere. Thirdly, to evaluate if there overuse by some clinicians who refer cases for cytogenetic study before exhausting other less expensive and time-consuming tests that may lead to the final diagnosis. Chromosomal analysis was performed on three hundreds and twenty five cases referred to the Cytogenetics Laboratory between June 2005 and May 2006 at King Fahad Medical City, Riyadh, Saudi Arabia [SA]. Indications for referrals for exclusion of chromosomal abnormalities was multiple congenital anomalies, dysmorphic features, unclassified mental retardation, developmental delay, primary amenorrhea, recurrent abortions and positive consanguinity. Data were collected from the referred patients' files. Lymphocyte culture was carried out according to standard procedures. Various types of chromosomal anomalies were recorded in 39 [12%] of the studied group of those, 35 [89.7%] showed numerical chromosomal abnormalities in the form of trisomy 21 [28; 71.7%]; trisomy 18 [2; 5.1%], trisomy 13 [2; 5.1%]; trisomy X [1; 2.5%] and monosomy 21 [2; 5.1%]. The remaining cases [4] showed structural chromosomal abnormalities in the form of dysmorphic features; 2 [5.1%]; mental retardation; 1 [2.5%] and Turner syndrome; 1 [2.5%]. Our results were compared to other studies results in SA and worldwide. Trisomy 21 was the most frequent chromosomal abnormality in this study. This study in addition to other similar studies in the same community figure out the chromosomal aberrations pattern in this area. It was concluded that awareness of the chromosomal aberrations frequencies will help clinicians working in Saudi Arabia and surrounding countries to determine the priority of requesting cytogenetic study in individual cases