Myofibrillary myopathy due to the ZASP mutation Ala147Thr. Two cases with exclusively distal leg involvement

This article describes two patients with late onset myofibrillary myopathy due the ZASP mutation Ala147Thr. The Z-band alternatively spliced PDZ motif containing protein (ZASP) is a sarcomeric protein and interacts with alpha-actinin at the Z-disk. So far, myopathy due the ZASP mutation Ala147Thr was usually associated with distal and proximal involvement. The two patients with the ZASP mutation Ala147Thr described here showed only distal involvement of the legs without proximal weakness and involvement of the upper limb 6 and 19 years after onset of muscle weakness, respectively.