|Number of repeats||Counts (alleles)||Percentage|
Overview of repeats
Expanded stretches of inserted TTTCA repeats in the intron 1 of YEATS2 gene has been described by Yeetong et al. (2019), causing familial adult myoclonic epilepsy type 4 (FAME4) disease. They found this in one Thai family with 21 members (13 affected and 8 unaffected). In one affected member, 819 repeats of TTTTA in conjunction with 221 repeats of TTTCA was found. The allele size for all affected members ranged from 5 to 8 kb which corresponds to approximately 1000-1600 pentanucleotide repeats (including expansions of both repeat unit). Configuration of the mutant sequence was determined as follows: (TTTTA)exp(TTTCA)exp. No TTTCA repeats were found in the unaffected family members nor any of the 1116 control subjects. Moreover, four of the healthy control subjects had TTTTA expansions (in the range of 719-1219 repeats), collectively suggesting the pathogenic role of TTTCA repeats (Yeetong et al., 2019).