Use of Array Comparative Genomic Hybridization for the Diagnosis of DiGeorge Syndrome in Saudi Arabian Population.

DiGeorge syndrome (DGS) is a genetic disorder known as a clinically variable syndrome with over 180 associated phenotypic features. It is caused by a common human deletion in the 22q11.2 chromosomal region and currently is affecting approximately 1 in 4,000 individuals. Despite the prevalence of inherited diseases mainly due to consanguineous marriages, the current diagnosis of DGS in Saudi Arabia is mainly based on conventional high-resolution chromosome banding (karyotyping) and FISH techniques. However, advanced genome-wide studies for detecting microdeletions or duplications across the whole genome are needed. The aim of this study is to implement and use aCGH technology in clinical diagnosis of the 22q11.2 deletion in Saudi Arabian DGS patients and to confirm its effectiveness compared to conventional FISH and chromosome banding techniques. Thirty suspected DGS patients were assessed for chromosome 22q11.2 deletion using high-resolution G-banding, FISH, and aCGH. The aCGH results were compared with those obtained by the other 2 cytogenetic techniques. G-banding detected the 22q11.2 deletion in only 1 patient in the cohort. Moreover, it detected additional chromosomal aberrations in 3 other patients. Using FISH, allowed for detection of the 22q11.2 deletion in 2 out of 30 patients. Interestingly, the use of aCGH technique showed deletions in the chromosome 22q11.2 region in 8 patients, indicating a 4-fold increase in diagnostic detection capacity compared to FISH. Our results show the effectiveness of aCGH to overcome the limitations of FISH and G-banding in terms of diagnostic yield and allow whole genome screening and detection of a larger number of deletions and/or duplications in Saudi Arabian DGS patients. Except for balanced translocations and inversions, our data demonstrate the suitability of aCGH in the diagnostics of submicroscopic deletion syndromes such as DGS and most chromosomal aberrations or complex abnormalities scattered throughout the human genome. Our results recommend the implementation of aCGH in clinical genomic testing in Saudi Arabia to improve the diagnostic capabilities of health services while maintaining the use of conventional cytogenetic techniques for subsequent validation or for specific and known aberrations whenever required.

Urinary enzymes and microalbuminuria as indicators of renal involvement in patients with diabetes mellitus in saudi arabia.

There is a high prevalence of diabetes mellitus in the population of Saudi Arabia with the majority having non-insulin dependent diabetes mellitus (NIDDM). Random mid-day urine samples were obtained from 100 male [37 insulin dependants DM (IDDM) and 63 NIDDM] and 100 female (51 IDDM and 49 NIDDM) diabetic patients. Eighty-four patients were hypertensive (46 males and 28 females). One hundred and fifty-five subjects, not under medication and without clinical evidence of renal disease, hypertension, or diabetes mellitus were used as controls. Two urinary enzymes, N-acetyl-beta-D-glucosaminidase (NAG) and alanine amino-peptidase (AAP) were measured in the urine, together with total protein and creatinine concentration. Microalbuminuria, glucose and pH were measured using test strips. Increased levels of both NAG and AAP were found in the diabetic subjects. Increased excretion of both these enzymes as well as microalbuminuria was found in the hypertensive groups. The high levels of urinary enzymes found, suggest that renal complications were prevalent in the groups studied. Because of the high incidence of diabetes in Saudi Arabia, a screening program should be established which would include urinary biomarkers for the early detection of renal damage.