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Frontiers in Biology

Front. Biol.    2018, Vol. 13 Issue (6) : 464-468
Prevalence of fragile X syndrome among patients with mental retardation in the west of Iran
Peyman Hadi1, Karimeh Haghani2, Ali Noori-Zadeh3, Salar Bakhtiyari2()
1. Department of biology, Sanandaj Branch, Islamic Azad University, Kurdistan, Iran
2. Department of Clinical Biochemistry, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
3. Department of Clinical Biochemistry, Faculty of Paramedicine, Ilam University of Medical Sciences, Ilam, Iran
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BACKGROUND: Fragile X syndrome (FXS), an X-linked disorder, is the most common cause of inherited mental retardation. This is caused by a trinucleotide CGG repeat expansion (>200) on the fragile X mental retardation 1 gene (FMR1) becoming methylated leading to a deficiency or absence of the FMR1 protein. Determining FXS prevalence in the mentally retarded individuals in the west of Iran was the aim of this study.

METHODS: 200 patients with moderate mental retardation who were clinically suspicious to FXS were screened using cytogenetic and molecular methods. Blood samples were collected and cultured in the specific culture media. The G-Banding method was used for karyotyping and DNA sequencing performed for verifying the results of the cytogenetic tests.

RESULTS: 16 patients (8%) were found to have fragile X syndrome. The results showed that there is no significant association between the fragile X syndrome and economic status and place of residence, however, the relationship between fragile X syndrome and mental retardation in the family history is significant.

CONCLUSION: The frequency of FXS was similar to other reports in the preselected patients. For diagnosis of FXS, chromosome analysis must be accompanied by molecular studies.

Keywords genetic diseases      inborn      FMR1      karyotype      diagnosis      mental retardation     
Corresponding Author(s): Salar Bakhtiyari   
Online First Date: 30 July 2018    Issue Date: 30 November 2018
 Cite this article:   
Peyman Hadi,Karimeh Haghani,Ali Noori-Zadeh, et al. Prevalence of fragile X syndrome among patients with mental retardation in the west of Iran[J]. Front. Biol., 2018, 13(6): 464-468.
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Peyman Hadi
Karimeh Haghani
Ali Noori-Zadeh
Salar Bakhtiyari
Age No. of patients %
≤5 y 7 3.5
>5-10 y 52 26
>10-15 y 78 39
>15-20 y 63 31.5
Total 200 100
Tab.1  Distribution of the mental retardation males according to the age of diagnosis
Fragile X-related features Not seen Minor Medium Severe
Long face 80 31 34 55
Large prominent ears 113 25 18 44
Hypre-extensible joints 75 50 26 63
Macro-orchidism 166 0 0 34
Hyperactivity 21 34 50 95
Autistic features 72 30 37 61
Biting the hand 131 14 15 40
Unusual speech pattern 33 70 31 66
Tab.2  Frequency of fragile X features in the mental retardation males
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