Because the tandem repeats have identical sequence to one another, base pairing between two DNA strands can take place at multiple points along the sequence. This may lead to the formation of loop out structures during DNA replication or DNA repair synthesis. This may lead to repeated copying of the repeated sequence, expanding the number of repeats. Additional mechanisms involving hybrid RNA:DNA intermediates have been proposed. Diagnosis
See also
C9orf72
RAN translation

References
External links
Trinucleotide+Repeat+Expansion at the US National Library of Medicine Medical Subject Headings (MeSH)
GeneReviews/NCBI/NIH/UW entry on DRPLA
National Institute of Neurological Disorders and Stroke
Genetics Home Reference
Transient lingual papillitis  are painful, hypertrophic, red and white lingual papillae on the tongue. Cause
Transient lingual papillitis can affect males and females as early as 3 years of age. In many cases, the cause is unknown. Some dental professionals believe the inflammation is due to chronic irritation from teeth, fillings, or dental appliances. Stress, poor nutrition, smoking, and alcohol use may also be initiating factors. == References ==