Table 3.
Repeat expansion details
| Gene | Disease | Inheritance | Location of repeat in gene | Repeat unit | Normal repeat size | Premutation repeat size | Pathogenic repeat size |
|---|---|---|---|---|---|---|---|
| CNBP | DM2 | AD | Intron | CCTG | <27 | 27–74 | >74 |
| DMPK | DM1 | AD | 3′ UTR | CTG | 5–35 | 36–49 | >49 |
| RFC1 | CANVAS | AR | Intron | AAGGG (pathogenic) AAAAG (benign) AAAGG (benign) |
11 (AAAAG) | n/a | >400a |
-
aSOC for RFC1 repeat expansions is not suited to detect full repeat sizes. It uses a combination of locus-spanning PCR, resulting in allelic dropouts for repeats >120 units, and RP-PCR to detect the repeats up to 20 units. For the sake of this technical study, repeat sizes >20 units were already considered expansions irrespective of their pathogenicity. Table adjusted from van der Sanden et al. (2021).
