A clinical study of mentally retarded children with fragile X syndrome in Saudi Arabia

Background: Studies on fragile X syndrome are scarce in Saudi Arabia and other countries of the Arabian Peninsula. The few studies previously done have either been in the form of case reports or those performed on institutionalized mentally retarded patients. The aim of this study was to determine the prevalence of fragile X syndrome among cases with mental retardation who have been referred to the pediatric neurology clinics of King Khalid University Hospital (KKUH) in Riyadh. Patients and Methods: Cytogenetic studies were performed in 94 cases who were referred to the pediatric neurology clinics of KKUH because of mental retardation and/or delayed milestones of development, From July 1995 to December 1997. Results: Six male probands (6.4%) showed the classic fragile X chromosome and another six (including a four-year-old girl) were detected, following extension of the cytogenetic studies to all 32 first-degree relatives. Affection of more than one sibling was ascertained in four families. One family had four brothers with fragile X syndrome, whereas another formed part of a large kindred with twelve males and five females who were mentally retarded. A clinical, physical and psychological screening checklist was applied to the eleven affected males. Large testicular size, long face and short attention span were the most frequent features, and each was detected in nine patients (82%). Pes planus and history of delayed speech were found in eight patients (73%). Conclusion: The study showed that the fragile X syndrome clinical screening checklist that has been applied in other populations might equally be valuable and applicable among the population of Saudi Arabia. However, the presence of pale blue eyes can be excluded and more weight given to positive family history of mental retardation. The study also highlighted the need for further emphasis on the orientation of primary care physicians to the most common clinical diagnostic features of fragile X syndrome.