CMT 2J : with MPZ Thr124Met mutation: clinico-electrophysiological and MRI study

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J Neurol. 2009 Jul 22.

Charcot-Marie-Tooth disease type 2J with MPZ Thr124Met mutation:

clinico-electrophysiological and MRI study of a family.

Gallardo E, García A, Ramón C, Maraví E, Infante J, Gastón I, Alonso A,

Combarros O, De Jonghe P, Berciano J.

Service of Radiology, University Hospital " Marqués de Valdecilla " , " Centro de

Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) " ,

University of Cantabria, 39008, Santander, Spain.

The purpose of the present study was to describe clinico-electrophysiological

features and lower limb muscle MRI findings in a CMT2J pedigree due to MPZ

Thr124Met mutation. We examined the proband, aged 56 years, and her affected

daughter and son, aged 30 and 29 years. Disease severity in terms of ability to

walk and run was established using a nine-point functional disability scale

(FDS). We administered the CMT neuropathy score (CMTNS) based on patient's

symptoms, neurologic examination and neurophysiologic testing. All three

patients had non-symptomatic Adie's pupil. The proband and her son presented

with late-onset lower limb sensorimotor neuropathy and pes cavus; the proband's

daughter had no signs of polyneuropathy. FDS score was 4 in the proband, 2 in

her son, and 0 (normal) in her daughter. In both symptomatic patients,

electrophysiological study showed a pattern of length-dependent axonal

neuropathy mainly involving lower limb nerves; this was normal in the other

patient. CMTNS was 18 in the proband, 12 in her son, and 0 (normal) in her

daughter. MRI of foot and leg musculature was normal in the proband's daughter,

whereas the other two patients showed massive fatty atrophy of intrinsic foot

musculature, extensive and diffuse fatty atrophy of leg muscles in the proband,

and mild distally accentuated fatty infiltration of calf muscles in her son.

Muscle edema, detected only in the proband's son, was present in 7 out of 22

(33%) of visualized leg muscles, whereas contrast enhancement occurred in 6 of

them. The reported mutation may manifest with either isolated Adie's pupil or

pupil abnormalities with late-onset sensorimotor length-dependent axonal

polyneuropathy, though the presence of pes cavus might indicate an earlier

onset. MRI examination helps to delineate an accurate extent of muscle

involvement in the disease.