Fragile -X(FMR1) Genetic Mutation:
Why Fragile – X (FMRI) - Genetic Mutation Test?
CLINICAL INFORMATION
Fragile X Syndrome (FXS) is also called Marker X Syndrome, Martin-Bell Syndrome etc. FXS is also represented as Fra(X)(Q27,3). This is named Fragile X syndrome because some patients with this disorder were found to have a segment of their X chromosome that appears to be fragile or broken and the location of FMR1 gene is located exactly at that same position where the X chromosome seems to be partially mutilated and distorted. Although it is not completely disconnected. FMR1 gene synthesizes a protein known as FMRP, which is necessary for normal brain development. FMRP protein is present in the brain, testes, ovaries etc, and is required for normal cell function it is also believed from scientific research that FMRP plays a key role in the development of connections between neurons (nerve cells) called synapses required for inter-communication between the neurons (nerve cells) in the brain. Fragile X Syndrome (FXS) is a genetic disorder is caused due to FMR1 gene mutation hence patients with FXS do not synthesize FMRP Protein. The mutation is caused by the duplication of the genetic segment “CGG”-Triplet repeat from 50 to sometimes 200 times (normal: if less than 45 CGG Repeats, intermediate: if in between 45 to 54 CGG repeats, Pre-mutation: if in between 55 to 200 CGG repeats and Full mutation: if greater than 200 CGG repeats). Therefore this test is also known as ‘Fragile X CGG repeat analysis’ or ‘Fragile X DNA Test’. Clinical manifestations with FXS include signs and symptoms of developmental delays (not sitting, walking or talking at the same time as other children with similar age groups), learning disabilities, social and behaviour problems (hyperactive, anxiety, trouble paying attention, speaking or acting without thinking hand flapping), intellectual disabilities, cognitive impairments etc. Moreover, patients with FXS also overlap with Autism Spectrum Disorders. Fragile X syndrome is also associated with certain other conditions such as Fragile X – Associated tremors/ataxia syndrome (FXTAS) or Fragile X – associated primary ovarian insufficiency (FXPOI) accompanied with infertility. Some of the salient features of FXS patients present with physical features that include a large head, long and narrow face, elongated chin, large and protruding ears, prominent jaw and forehead, flexible hyper extendable fingers, loose joints etc. Complications of FXS in certain cases also include seizures. Additional tests include suspected females with infertility, FSH levels, Pre-mature ovarian failure, primary ovarian insufficiency, irregular menses etc. methylation status and the presence of mosaicism – if it can be detected. Other tests include PCR, Southern Blot Analysis, karyotyping, chromosomal microarray analysis, Exome sequencing, and specific DNA test for Fragile X syndrome.
General Instructions:
Sample Requirement: Specimen - Blood sample collected from the vein or other specimen for DNA testing as per the guidance of the physician. Test Preparation: None.
NOTE - Sample for specimen collections may vary based on the patient’s condition/cases according to the patient’s presenting complaints/signs or symptoms:
SPECIMEN REQUIREMENT (Special or Rare Cases) - As instructed and guided by Physician / Clinician / Pathologist / as per Laboratory’s requirements, according to procedures and protocols.
This Multi-Specialty Clinical Referral Laboratory RTDIAGNOSTICS provides precise and accurate tests with an extensive range of testing services to the medical centres to help in the diagnosis and identification of pathology in the test specimens for infectious diseases and also to evaluate the function of organ systems of the patient. It prevents further complications and helps to stabilize and restore health to near normalcy at the earliest without delay.
