Table 4. Analysis of MTM1-LOVD missense mutations.
| Missense mutations | Nonsense mutations | ||||||
|---|---|---|---|---|---|---|---|
| Phenotype reported a | |||||||
| Protein domain | Residues involved (% of total protein) | n (% of total) | Severe | Mild/Moderate | Inconsistent | Unknown | n (% of total) |
| GRAM | aa 34–149 (19.1%) | 9 (12.3%) | 2 (22.2%) | 5 (55.6%) | 0 | 2 (22.2%) | 5 (15.6%) |
| RIDb | aa 162–265 (17.1%) | 28 (38.4%) | 15 (53.6%) | 7 (25.0%) | 3 (10.7%) | 3 (10.7%) | 6 (18.8%) |
| PTP | aa 274–434 (26.5%) | 28 (38.4%) | 18 (64.3%) | 5 (17.9%) | 1 (3.5%) | 4 (14.3%) | 3 (9.4%) |
| SID | aa 435–486 (8.5%) | 5 (6.8%) | 3 (60.0%) | 1 (20.0%) | 0 | 1 (20.0%) | 5 (15.6%) |
| Other | (28.8%) | 3 (4.1%) | 1 (33.3%) | 2 (66.7%) | 0 | 0 | 13 (40.6%) |
| Total | 73 | 39 | 21 | 4 | 9 | 32 | |
Abbreviations: aa, amino acid position within myotubularin protein (reference sequence NP_000243.1); GRAM, glucosyltransferase, Rab-like GTPase activators and myotubularins; PTP, protein tyrosine phosphatase; RID, Rac-induced recruitment domain; SID, SET-interacting domain.
a
Only phenotypes reported in male patients were considered for this analysis; the mild and moderate phenotypes were combined as several reports do not distinguish the two clinical classifications.
b
This domain partially overlaps desmin-binding region.