Affiliations: Department of Pediatrics, Genetics Unit, Faculty of
Medicine, Mansoura University, Mansoura, Egypt | Genetics Laboratories, Mansoura University Children's
Hospital, Mansoura, Egypt | Department of Pediatric Neurology, Mansoura University
Children's Hospital, Mansoura, Egypt
Note: [] Correspondence: Mohammad Al-Haggar, MD, Department of
Pediatrics, Faculty of Medicine, Mansoura University, Mansoura, Egypt. Tel.:
+96638982022; Fax: +96638951196; E-mail: [email protected]
Abstract: To screen children with idiopathic mental retardation (MR) using a
clinical Ten-Item Checklist (TIC) and to analyze high-risk fragile X syndrome
(FXS) cases by cytogenetic and molecular genetic techniques. This study was
conducted on 192 children with idiopathic MR enrolled from Pediatric clinics of
University Hospitals and MR institutes of Alexandria, Mansoura and Benha
Governorates, Nile Delta, Egypt (age range 2–14 years). Clinical scoring for
patients was done using TIC according to which patients were categorized either
positive checklist with score higher than 5 or negative with score less than 5.
Positive cases underwent cytogenetic analysis that provoke expression of
fragile sites on chromosome X and molecular genetic analysis for detection of
permutation among cases or their 1st degree relatives. Analyzing all cases: IQ
ranged from 30 to 80%, family history of MR was found in 28.6% and
consanguinity was positive in 26%. Positive checklist cases constituted 23.9%
and remainder 76.1% were negative checklist. The most frequent items in
positive cases were large prominent ears, hyper-extensible finger joints,
hyperactivity, and large narrow face with less common macro-orchidism. A
positive linear association was found between laboratory test positivity and
TIC score being stronger with cytogenetic analysis compared to polymerase chain
reaction (PCR) (P 0.001 and 0.02, respectively). Using TIC, 76.1% cases could
be eliminated from the waiting list of genetics laboratories. The relatively
weaker association of TIC score to PCR compared to cytogenetic analysis
together with areas under receiver operating characteristic curve 0.743 and
0.814 respectively denote the higher accuracy and sensitivity of PCR analysis
in final diagnosis of FXS.
Keywords: Fragile X syndrome, cytogenetics, molecular genetics, Egypt
