TIA1 and distal myopathy, Welander type: Moreover, a founder mutation affecting the TIA1 LCD (E384K) has been reported in Swedish/Finnish patients to cause Welander distal myopathy (WDM) [10, 15], a type of vacuolar myopathy with clinical and histopathological similarity to the myopathies caused by mutations a number of other genes that can also cause ALS/FTD (e.g. valosin containing protein and sequestosome-1) [8, 12].