Syndromes and Diseases Caused by Mutations Due to Expansion of DNA Trinucleotide

Overview

A novel type of mutation – due to expansion of DNA trinucleotide repeats – has been discovered about 10 yearsago. Nowadays 15 genetic syndromes and diseases caused by these mutations are known such as FRA X A syndrome,FRA X E syndrome, Kennedy syndrome spinobulbare muscle atrophy, Curschmann-Steinert syndrome of myotonicdystrophia, Huntington disease, Friedreich ataxia, spinocerebellare ataxias types I., II., III., VI., VII., VIII., XII. andTaylor’s oculopharyngeal muscle dystrophy. The mutations of instable trinucleotids represent some exceptions fromthe regular monogenic transmission such as premutation, genomic imprinting, generation anticipation (acceleration,accentuation), somatic mosaicism. A good understanding of their special properties is necessary for efficientinterdisciplinar collaboration of medical teams taking care for these patients and their families.

Key words:
triplet repeats, premutation, fragile X syndrome A and E, Curschmann-Steinert syndrome, Huntingtonchorea, Friedreich ataxia, spinocerebellar ataxias, Taylor syndrome oculopharyngeal muscle dystrophy.