We thank colleague Gourie-Devi for her valuable comments on our study.1 The large group of patients she described in her follow-up study2 shares many similarities with our patients such as the relatively long duration of the follow-up, the marked preponderance of affected men, and the stationary disease course. In the nomenclature of lower motor neuron syndromes, the term (brachial) monomelic amyotrophy has been interchangeably used with the term juvenile muscular atrophy of unilateral upper extremity, the name Hirayama gave the condition in 1959.3 This condition has been mainly described in India and Japan and affects predominantly young, male patients with involvement of C7-, C8-, and Th1-innervated muscles. The onset of disease in patients with a monomelic amyotrophy is often insidious, with slow progression over approximately 2 to 4 years, followed by a stationary phase.2,3 The prognosis seems favorable and, although bilateral involvement has been described in a minority of patients, a transition to progressive muscular atrophy or amyotrophic lateral sclerosis has not been described.
Van den Berg-Vos RM. Long-term Follow-up of Monomelic Amyotrophy of the Upper Limb—Reply. Arch Neurol. 2010;67(4):517-518. doi:10.1001/archneurol.2010.33