RETREG1 and Atrophy: In mixed breed dogs with chronic progressive proprioceptive ataxia manifesting as generalized muscle atrophy, mainly of the pelvic limbs, spontaneous knuckling, and self-mutilating wounds on the distal part of the pelvic limbs, a missense variant (c.656C > T, p.P219L) in the reticulophagy regulator 1 (RETREG1 or FAM134B) gene was pinpointed as the plausible causal variant [112].