Mondo Description Any neuronopathy, distal hereditary motor in which the cause of the disease is a mutation in the REEP1 gene.

Uniprot Description A disorder characterized by distal muscular atrophy mainly affecting the upper extremities, in contrast to other distal motor neuronopathies. These constitute a heterogeneous group of neuromuscular diseases caused by selective degeneration of motor neurons in the anterior horn of the spinal cord, without sensory deficit in the posterior horn. The overall clinical picture consists of a classical distal muscular atrophy syndrome in the legs without clinical sensory loss. The disease starts with weakness and wasting of distal muscles of the anterior tibial and peroneal compartments of the legs. Later on, weakness and atrophy may expand to the proximal muscles of the lower limbs and/or to the distal upper limbs. HMN5B is characterized by onset in the first or second decade of distal muscle weakness and atrophy, primarily affecting the intrinsic hand muscles, but also affecting the lower legs, resulting in abnormal gait and pes cavus.