Fragile X syndrome an X-linked disorder caused by expansion of the CGG trinucleotide repeat affecting the Fragile X mental retardation 1 (FMR1) gene on the X chromosome. X-linked dominant – males are more severely affected by this disorder than females. It is the most common inherited form of mental retardation and second only to Down’s syndrome as a cause of mental impairment. Mothers of affected patients are obligate gene carriers.
–
DNA probe to pinpoint the defective gene
Fragile X syndrome is associated with the following characteristics)
a) More common in boys
b) Most common form of inherited mental retardation
c) Involves the long arm of the X chromosome
d) Can be diagnosed with a blood test
e) Treatment is limited to symptomatic management