Molecular Characterization of X Chromosome Fragility In Idiopathic Mental Retardation
Heba Alla Ahmad Hosny Omar;
Abstract
Summary
T
he current study included 64 males with idiopathic mental retardation. All patients underwent, history taking, and full clinical examination, blood sample for DNA analysis to detect FMR1 genotyping using a new PCR-based approach that combines modification of the betaine protocol with a use of a CGG-targeted (chimeric) primer. 57.8% of cases were above 10 years and 42.2% were below 10 years, their IQ ranges from mental subnormal to profound. 12.5% of cases have full mutation, and 9.4 % had permutation. We found similar prevalence of the fragile X syndrome among mentally retarded individuals in Middle East as reported from Kuwait, Saudi Arabia and turkey. The high prevalence in Middle East was due to clinical preselection for DNA testing for FXS in mentally retarded males using a scoring list. The scoring list included family history of MR, long face, large prominent ears, hyperextensibility of the finger joints, macro-orchidism (in post pubertal males), hyperactivity, autistic features and unusual speech pattern.
Among enrolled cases, 57.1 % have positive family history for mental retardation either from the paternal or maternal side, 35.7% have macroorchadism, 57.1% had autistic like behavior, 64.3% have hyperactivity, 71.4 % have speech problems, 50% have long faces, 57.1% have hyperextensability of joints, 78.6% have large ears, 35.7 % have a history of seizures and or abnormal EEG finding. There was a significant association between large prominent ears, hyperextansbility of joints and macro-orchadism (in postpubertal males) and FXS diagnosis.
The mean score for fragile X group with permutation was 3.64 and for fragile X full mutation was 5.5.indicating that genetic analysis of the fragile X syndrome can be restricted to selected males. Using a simple checklist with current new PCR technique would eliminate most of fragile X testing leading to negative results without missing any affected male.
The present study was conducted using a rapid screening method for fragile X syndrome among male patients with isolated idiopathic mental retardation. This method is a rapid, inexpensive screening tool that would be capable of detecting all expanded alleles in both males and females.
T
he current study included 64 males with idiopathic mental retardation. All patients underwent, history taking, and full clinical examination, blood sample for DNA analysis to detect FMR1 genotyping using a new PCR-based approach that combines modification of the betaine protocol with a use of a CGG-targeted (chimeric) primer. 57.8% of cases were above 10 years and 42.2% were below 10 years, their IQ ranges from mental subnormal to profound. 12.5% of cases have full mutation, and 9.4 % had permutation. We found similar prevalence of the fragile X syndrome among mentally retarded individuals in Middle East as reported from Kuwait, Saudi Arabia and turkey. The high prevalence in Middle East was due to clinical preselection for DNA testing for FXS in mentally retarded males using a scoring list. The scoring list included family history of MR, long face, large prominent ears, hyperextensibility of the finger joints, macro-orchidism (in post pubertal males), hyperactivity, autistic features and unusual speech pattern.
Among enrolled cases, 57.1 % have positive family history for mental retardation either from the paternal or maternal side, 35.7% have macroorchadism, 57.1% had autistic like behavior, 64.3% have hyperactivity, 71.4 % have speech problems, 50% have long faces, 57.1% have hyperextensability of joints, 78.6% have large ears, 35.7 % have a history of seizures and or abnormal EEG finding. There was a significant association between large prominent ears, hyperextansbility of joints and macro-orchadism (in postpubertal males) and FXS diagnosis.
The mean score for fragile X group with permutation was 3.64 and for fragile X full mutation was 5.5.indicating that genetic analysis of the fragile X syndrome can be restricted to selected males. Using a simple checklist with current new PCR technique would eliminate most of fragile X testing leading to negative results without missing any affected male.
The present study was conducted using a rapid screening method for fragile X syndrome among male patients with isolated idiopathic mental retardation. This method is a rapid, inexpensive screening tool that would be capable of detecting all expanded alleles in both males and females.
Other data
| Title | Molecular Characterization of X Chromosome Fragility In Idiopathic Mental Retardation | Other Titles | التشخيص الجزيئى لهشاشة كروموسوم X بين المصابين بالتأخر العقلى غير معروف السبب | Authors | Heba Alla Ahmad Hosny Omar | Issue Date | 2015 |
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