Trinucleotide repeat disorders

Trinucleotide repeat disorders


Trinucleotide repeat disorders are caused by the abnormal presence of an expanded sequence of trinucleotide repeats. 

The hallmark of these disorders is the concept of anticipation. This refers to the amplification of the number of repeats over successive generations. This results in an earlier age of onset and often a more sever form of the condition.

The following table lists the trinucleotide repeat disorders and illustrates the repeats considered to give rise to the condition:

ConditionRepeat sequence involved
Fragile X syndromeCGG
Myotonic dystrophyCTG
Huntington's diseaseCAG
Friedreich's ataxiaGAA
Spinocerebellar ataxiaCAG

The mutations seen in trinucleotide repeat disorders are referred to as 'dynamic'