Deteksi Sindrom Fragile X dengan Pemeriksaan Sitogenetik dan PCR Pada Siswa SLB Hj. Soemiyati Himawan Semarang

Abstract

Background: Mental retardation is a condition in which the intellectual function is significantly below the average and accompanied by limitation in adaptive behavior. Causes of mental retardation varies widely, in which genetic factors play role for about 25-50%. Fragile X syndrome is the second most genetic disease that cause mental retardation after Down syndrome. Cytogenetics and molecular genetic examination should be done to confirm the presence of Fragile X syndrome. The aim of this study is to determine the number of students with Fragile X syndrome at HSH SLB. Methods: This descriptive observational study used non-probability sampling with consecutive sampling method. Thirty eight students at special school who met the inclusion criteria were being examined with cytogenetic and molecular genetic examination (PCR). Results: Two out of 38 samples were suspicious of Fragile X Syndrome based on cytogenetic examination. Two samples were confirmed as Fragile X Syndrome based on PCR, one showed full mutation in the FMR1 gene, while the other has a mosaic pattern premutation-full mutation. Other chromosomal abnormalities obtained in this study was Down Syndrome trisomy 21 in one sample. Conclusion: Patients with Fragile X syndrome who have been examined by PCR still needs confirmation with Southern Blot examination as a definitive diagnostic test of Fragile X syndrome. Tracing the family of the patient also important in order to figure out other family members who have similar genetic abnormalities. Keywords: Fragile X Syndrome, cytogenetic examination, PCR for FMR1 gene