Trinucleotide Repeat Expansion

**Definition:** An increased number of contiguous trinucleotide repeats in the DNA sequence from one generation to the next. The presence of these regions is associated with diseases such as FRAGILE X SYNDROME and MYOTONIC DYSTROPHY. Some CHROMOSOME FRAGILE SITES are composed of sequences where trinucleotide repeat expansion occurs.

**Tree numbers:** - G02.111.570.080.708.800.140.865 - G02.111.570.080.708.800.500.850.200 - G05.360.080.708.800.074.865 - G05.360.080.708.800.500.850.200 - G05.360.340.024.189.220.865 - G05.360.340.024.850.500.850.200 - G05.365.590.220.865 - G05.558.220.865

**Synonyms:** - Expanded Trinucleotide Repeat