Which of the following is an example of Trinucleotide repeat mutation ?

Ans. is 'd' i.e., All of the above Trinucleotide repeat mutation In this type of mutation a codon (i.e. trinucleotide sequence) undergoes amplification and the same codon is repeated continuously so many times in the chain. Diseases associated with trinucleotide repeat mutation are Huntington's disease (CAG repeat), Spinocerebellar ataxia (CAG repeat), friedreich ataxia (GAA repeat), fragile-X-syndrome (GGG or GCC repeat), dystrophia myotonica (CTG/CUG repeat), X-linked spinobulbar muscular atrophy (CAG repeat) and dentorubral pallidolusian atrophy (CAG repeat).