J Orthopaed Traumatol (2010) 11:195–201 DOI 10.1007/s10195-010-0114-y R E V I E W A R T I C L E Pes cavus and hereditary neuropathies: when a relationship should be suspected S. Piazza • G. Ricci • E. Caldarazzo Ienco • C. Carlesi • L. Volpi • G. Siciliano • M. Mancuso Received: 7 May 2010 / Accepted: 25 September 2010 / Published online: 21 October 2010 The Author(s) 2010. This article is published with open access at Springerlink.com Abstract The hereditary peripheral neuropathies are a clinically and genetically heterogeneous group of diseases of the peripheral nervous system. Foot deformities, including the common pes cavus, but also hammer toes and twisting of the ankle, are frequently present in patients with hereditary peripheral neuropathy, and often represent one of the ﬁrst signs of the disease. Pes cavus in hereditary peripheral neuropathies is caused by imbalance between the intrinsic muscles of the foot and the muscles of the leg. Accurate clinical evaluation in patients with pes cavus is necessary to exclude or conﬁrm the presence of peripheral neuropathy. Hereditary peripheral neuropathies should be suspected in those cases with bilateral foot deformities, in the presence of family history for pes cavus and/or gait impairment, and in the presence of neurological symptoms or signs, such as distal muscle hypotrophy of limbs. Herein, we review the hereditary peripheral neuropathies in which pes cavus plays a key role as a ‘‘spy sign,’’ discussing the clinical and molecular features of these disorders to high- light the importance of pes cavus as a helpful clinical sign in these rare diseases. Keywords Pes cavus Hereditary peripheral neuropathy Neurological evaluation Multidisciplinary management S. Piazza G. Ricci E. Caldarazzo Ienco C. Carlesi L. Volpi G. Siciliano M. Mancuso (&) Department of Neuroscience, Neurological Clinic, University of Pisa, Via Roma 67, 56126 Pisa, Italy e-mail: mmancuso@inwind.it Introduction Pes cavus is a foot deformity characterized by a high arch of the foot that does not ﬂatten with weight bearing; the deformity can be located in the forefoot, midfoot, hindfoot, or in a combination of all these sites (Figs. 1, 2). Pes cavus is a common ﬁnding in the general population, with prevalence of approximately 10% [1]. Frequently, pes cavus may be a sign of an underlying neurological disorder, including spinal cord and peripheral nerve pathologies, such us spino-cerebellar ataxia and hereditary peripheral neuropathies. A previ- ous retrospective analysis of patients undergoing pes cavus surgery [2] revealed that almost one-third of apparently idiopathic cases suffered from a neurological disease. Herein, we discuss the hereditary peripheral neuropa- thies (HPN) in which pes cavus plays a key role as a ‘‘spy sign.’’ A clear, complete, and detailed review of clinical and molecular features of these rare disorders may be useful in clinical management and differential diagnosis of patients who present with pes cavus as almost single sign of disease. Hereditary peripheral neuropathies (HPN) are a hetero- geneous group of peripheral nerve disorders, clinically characterized by sensorial and/or motor impairment, with reduction or absence of deep tendon reﬂexes [3]. Foot deformities, including pes cavus, hammer toes, and twisting of the ankle, are commonly present in some HPN forms, such as Charcot–Marie–Tooth (CMT) disease, hereditary neuropathy with predisposition to pressure pal- sies (HNPP), and distal hereditary motor neuropathy (DHMN) [4], but are uncommon in the other HPN. We will therefore discuss only the clinical features and genetic basis of HPN associated with pes cavus. 123