European Journal of Human Genetics ( IF 5.2 ) Pub Date : 2020-09-24 , DOI: 10.1038/s41431-020-00729-1 Patra Yeetong 1 , Chaipat Chunharas 2, 3 , Monnat Pongpanich 4 , Mark F Bennett 5, 6, 7 , Chalurmpon Srichomthong 8, 9 , Nath Pasutharnchat 2 , Kanya Suphapeetiporn 8, 9 , Melanie Bahlo 5, 6 , Vorasuk Shotelersuk 8, 9
Benign adult familial myoclonic epilepsy type 1 (BAFME1) in several Japanese and Chinese families has recently been found to be caused by pentanucleotide repeat expansions in SAMD12. We identified a Thai family with six members affected with BAFME. Microsatellite studies suggested a linkage to the BAFME1 region on chromosome 8q24. Subsequently, long-read whole-genome sequencing showed the (TTTTA)446(TTTCA)149 in intron 4 of SAMD12 in an affected member. Repeat-primed PCR and long-range PCR revealed that the pentanucleotide repeat expansions segregated with the disease status. Our Thai family is the first non-Japanese and non-Chinese family with BAFME1. SNP array showed that the aberrant repeats had the same haplotype as those previously determined in Japanese and Chinese patients suggesting a common ancestry. The variant is estimated to arise ~12,000 years ago.