Genetic abnormality in fragile x syndrome-

Fragile X syndrome is the prototype of diseases in which the mutation is characterized by a long repeating sequence of 3 nucleotides. These mutations are characterized by amplification of a sequence of three nucleotides. Although the specific nucleotide sequence that undergoes amplification differs in various disorders, almost all affected sequences share the nucleotides Guanine (G) and cytosine (C). Also, know - It is the second most common cause of mental retardation after Down's syndrome. It is an X linked disorder characterized by an inducible cytogenetic abnormality in the X chromosome and an unusual mutation within the familial mental retardation (-1 FMR-1 gene). Trinucleotide Repeat disorders Expansions affecting the non-coding region Fragile X syndrome Frederich's ataxia Myotonic dystrophy Expansions affecting coding region Spinobulbar muscular atrophy Huntington's disease Dentatorubral pallidoluysian Spinocerebellar ataxia type 1 Spinocerebellar ataxia type 2 Spinocerebellar ataxia type 3 Spinocerebellar ataxia type 6 Spinocerebellar ataxia type 7