Figure 1. The muscle weakness phenotype of the Mariusz mutant.

(A) The original pedigree in which the Mariusz mutant was identified. (B) Grip-strength comparison using 3-month-old Mariusz homozygotes (n = 30) and wild type (n = 26) littermate controls. The average force generated by wild type mice has been set as 100%. Mean and SD are shown. The differences are highly significant; P-values (Student's t test): *** P<0.0001. (C) Close-up photos showing the different grasp of Mariusz homozygotes (Mz/Mz) and wild type littermate controls. (D) Example of clasping phenotype observed in a Mariusz homozygote and littermate control. (E) A wire manoeuvre test of Mariusz mice and littermate controls. Scores are as follows: 0 = mouse swings hindlegs on to bar and makes way to edge rapidly; 1 = mouse swings hindlegs on to bar after a delay and makes way to edge rapidly; 2 = mouse is suspended by using underarms to straddle bar and does not lift hind limbs, eventually falls; 3 = mouse falls after short delay; 4 = mouse falls immediately.