Another mouse model in which muscle spindles fail to form – produced by a deletion in the cytoplasmic dynein heavy chain 1 gene (Dync1h1) – also exhibits an unsteady jerky and wobbling gait and splayed hindlimbs and has a pure proprioceptive sensory neuropathy without any motor involvement (Chen et al., 2007). The gene discussed is DYNC1H1; the disease is Sensory neuropathy.