الوصف
Fragile X syndrome is the most prevalent cause of inheritable mental retardation. This X-linked disorder is caused by the absence of the fragile X mental retardation protein (FMRP) due to an expansion of a polymorphic CGG repeat in the 5’ untranslated region of the FMR1 gene. This expansion in the CGG repeat to more than 200, results in the methylation of the CGG and the surrounding promoter region of the FMR1 gene inhibiting FMR1 transcription and causing absence of the protein product.
دواعي الإستعمال
This test is used in the diagnosis of Fragile X syndrome. Although the number of CGG repeats is highly variable, the majority of normal individuals have around 30 repeats that are interrupted by two AGGs. Individuals with fragile X pre-mutation have CGG repeats between 50 and 200. Pre-mutation gene may become unstable when passed maternally and cause Fragile X syndrome in the foetus. Moreover, the length of the CGG repeat in pre-mutation may increase in subsequent generations.
نوع العينة والكمية والشروط
5-10 ml EDTA Blood Room Temperature
إحتياطات خاصة
Collect in EDTA vacutainer tube. Avoid contamination with DNA of phlebotomist. Avoid Haemolysed samples. Do not freeze samples. Send tube unopened.
المعدل الطبيعي
By Report
