Yuill and Lynch (1974) reported a family in which 3 males of successive generations and the sister of the youngest male had a neuromuscular disorder characterized by severe foot deformities and weakness and wasting of the distal lower ... Yuill and Lynch (1974) reported a family in which 3 males of successive generations and the sister of the youngest male had a neuromuscular disorder characterized by severe foot deformities and weakness and wasting of the distal lower limb muscles resulting in delayed walking, or wide-based gait; the girl could only take a few steps. Proximal muscles showed a less severe weakness and wasting. The condition was present at birth and showed little progression. One patient had a spastic gait with lower limb hyperreflexia, but the others had lower limb areflexia; all had extensor plantar responses. Three of the patients had arthrogryposis multiplex, with limited hip, knee, and ankle movement. Foot deformities included bilateral talipes equinovalgus, equinus, and calcaneovalgus. There was no ataxia or sensory defects. Skeletal muscle biopsy from 1 patient showed muscle fiber atrophy, some large fibers with internal nuclei, and increased fibroelastic and fatty tissue. There were signs of both denervation and myopathy. Several abnormal axons with terminal sprouting and swelling were seen following a tortuous course along the abnormal muscle fibers. Yuill and Lynch (1974) concluded that the disorder was an inherited neuropathy, possibly a spinal muscular atrophy, with secondary myopathic changes. See also congenital nonprogressive distal spinal muscular atrophy (600175), caused by mutation in the TRPV4 gene (605427), which shows similar features.