Table 2.
| No. | Exon | Mutation | Age at onset | Duration (month) | Site of onset | Cognitive decline | |
|---|---|---|---|---|---|---|---|
| 1 | 14 | p.G472VfsX57 | c.1420_1421 ins GT | 26 | 12 | L/E | - |
| 2 | 14 | p.G497AfsX527 | c.1485 del A | 18 | 11 | Neck, U/E(P) | MR |
| 3 | 14 | p.K510E | c.1528 A > G | 28 | 10 | Neck | - |
| 4 | 14 | p.S513P | c.1537 T > C | 62 | 84 | L/E | - |
| 5 | 14 | p.S513P | c.1537 T > C | 52 | 156 | L/E | - |
| 6 | 14 | p.R514S | c.1542 G > C | 42 | 43 | Bulbar | - |
| 7 | 14 | p.R514S | c.1542 G > C | 51 | Bulbar, U/E(P) | - | |
| 8 | 15 | p.H517P | c.1550 A > C | 31 | 24 | Bulbar | - |
| 9* | 15 | p.H517D | c.1551 C > G | 39 (n = 2) | 20 | Neck, U/E(P) | - |
| 10 | 15 | p.Q519E | c.1555 C > G | 60 (n = 2) | alive > 192 ‡ | L/E | - |
| 11* | 15 | p.R521S | c.1561 C > A | 35.5 (n = 2) | 49 | Bulbar, U/E(P) | - |
| 12* | 15 | p.R521L | c.1562 G > T | 38.5 (n = 2) | 17 | Neck, U/E(P) | FTD |
| 13* | 15 | p.R521L | c.1562 G > T | 35.7 (n = 13) | 17.7 | Neck, U/E(P) | - |
| 14 | 15 | p.R521L | c.1562 G > T | 44 | Neck | - | |
| 15 | 15 | p.R521H | c.1562 G > A | 39 | L/E | - | |
| Average | 40.1 | 40.3 |
We have identified 11 mutations in all 15 families, concentrated in Ex14 and Ex15. Most are young-onset and rapidly progressing, with spherical symptoms and cervical spinal cord region onset. p.Q519E and p.S513P families have older age, slightly slower progression, and lower extremity onset.
n number of patients, FTD frontotemporal dementia, L/E lower extremity, MR mental retardation, U/E(p) upper extremity with proximal dominancy, − absent