ABSTRACT
The PRPS1 gene encodes phosphoribosyl pyrophosphate synthetase 1 (PRS-1). The phenotypes associated with PRPS1 mutations include DFN2 (mild PRS-1 deficiency), X-linked Charcot-Marie-Tooth disease type 5 (CMTX5) (moderate PRS-1 deficiency), Arts syndrome (severe PRS-1 deficiency), and PRS-1 superactivity1. CMTX5 is a very rare hereditary neuropathy characterized by deafness, optic atrophy, and polyneuropathy. We herein report a Japanese patient with CMTX5 who had a novel hemizygous mutation c.82 G>C in PRPS1. Despite showing a typical clinical picture, the decrease in enzyme activity measured in the patient's erythrocytes was milder than in previously reported cases.
Subject(s)
Charcot-Marie-Tooth Disease , Polyneuropathies , Charcot-Marie-Tooth Disease/genetics , Hearing Loss, Central , Humans , Japan , Muscular Disorders, Atrophic , Mutation/genetics , Optic Atrophies, Hereditary , Ribose-Phosphate Pyrophosphokinase/geneticsABSTRACT
Unilateral enlargement of the calf in a 57-year-old man with S1 radiculopathy is described in this case report. Short tau inversion recovery-weighted imaging provided evidence of selective hypertrophy and a high signal intensity of the gastrocnemius and soleus. Histopathological analysis of the gastrocnemius revealed an endomysial inflammatory infiltrate and marked denervation lesions. Marked signs of denervation are suggestive of focal myositis secondary to neurogenic damage. The patient was treated with an oral corticosteroid (30 mg/day) and the calf hypertrophy was dramatically reduced within 5 weeks. Our case indicates that steroid therapy should be tried because it may be a potentially treatable disease.
