HMSN Type Research Articles

Somatosensory evoked potentials in charcot-marie-tooth disease

SEPs by median nerve stimulation have been performed in 18 adult patients (12 males and 6 females) affected by CMTD (type I, 13 patients; type II, 5 patients). All patients underwent MCV studies (median, ulnar, peroneal nerve), SCV studies (median and sural nerve), VEP, BAEP. N9 and N13 peaks were not detectable in 7/13 and 5/13 cases (HMSN type I) while cortical N19 were always recorded. Latency values of all responses were moderately or markedly delayed in all cases with HMSN type I, but proved normal or slightly delayed in HMSN type II cases. The prolonged latencies were mainly related to slowing of peripheral conduction. N9-N13 inter-peak was abnormally prolonged in 2 cases and N13-N19 in 2 other cases; both were prolonged in another case. In another 3 cases an abnormal BAEP was recorded. The few patients with abnormal CCT and BAEP probably belong to a borderline form between HMSN and hereditary ataxias.

Linkage analysis of Charcot-Marie-Tooth neuropathy (HMSN type I)

Fifteen HMSN families with 218 members and documented male-to-male transmission and slow motor nerve conduction velocities were informative for linkage to Duffy blood group (Fy), antithrombin III cDNA probe (AT3) and renin (REN). Our data support linkage to Fy in 8 families (lod score = 2.45 at θ = 0) consistent with HMSN type IB. Linkage to AT3 (lod score = 1.28 at θ = 0) and linkage of Fy to AT3 (lod score = 1.61 at θ = 0) is also supported in 3 of the 8 original families. Linkage to REN (lod score = 0.78 at θ = 0), linkage of Fy to REN (lod score = 0.89 at θ = 0), and linkage of AT3 to REN (lod score = 0.88 at θ = 0) is supported in only 2 of the 8 original families. Linkage to Fy was rejected in seven families, consistent with HMSN type IA (lod score = −4.34 at θ = 0.05). Linkage to AT3 was rejected in 12 families (lod score = −9.52 at θ = 0.05). Linkage to REN was rejected in 13 families (lod score = −11.07 at θ = 0.05). Our data provide support for the concept of genetic heterogeneity in CMT hypertrophic neuropathy (HMSN type I). The linkage of HMSN type IB to Fy seems to be tighter than to AT3 and REN, strongly suggesting the mapping of HMSN type IB locus on the proximal part of the long arm of chromosome 1, close to the centromere.

Cardiomyopathy in Patients With Hereditary Motor and Sensory Neuropathy

Twelve affected persons in the third decade of life or later, and the 14 nearest age- and sex-matched unaffected relatives, of a large kindred with autosomal dominant hereditary motor and sensory neuropathy not linked to the Duffy blood group (HMSN type IA) were assessed for arrhythmia and cardiomyopathy. Cardiac abnormalities were no more frequent in the affected persons than in the unaffected relatives. The heart of a patient with HMSN type II who had died of complications of cardiomyopathy was found to have rheumatic disease-type myocarditis with Aschoff bodies. The results of this study provide further evidence against an association of cardiomyopathy and HMSN.

Family with Roussy-Lévy syndrome

In five members belonging to a Swiss kinship the typical signs of Roussy-Levy's syndrome are described, such as disturbances of gait and of standing, areflexia, foot deformities, slight muscular weakness and atrophies, minimal sensory disturbances and the typical course of the disease. The patients have been examined electrophysiologically and disturbances of sensory conduction velocity and sensory nerve action potentials are described. The question whether Roussy-Lévy's syndrome represents a disease entity or not, is discussed. The authors feel that the syndrome belongs to HMSN type I.

Genetic linkage evidence for heterogeneity in Charcot-Marie-Tooth neuropathy (HMSN type I).

A genetic linkage study performed on a large family with autosomal dominant Charcot-Marie-Tooth neuropathy (HMSN type I) showed affected family members to have slow motor nerve conduction velocities, hypoactive tendon reflexes, and distal muscle weakness and atrophy. Results excluded close linkage of the neuropathy in this family to the Duffy blood group locus on chromosome 1. Previous studies in other families have shown positive linkage of HMSN type I to the Duffy locus. The present results provide support for the concept of genetic heterogeneity in HMSN type I. Comparison of this new family with the previous families showing linkage to Duffy reveals that the hereditary neuropathy not linked to the Duffy locus may have less severe slowing of motor nerve conduction velocities and less prominent onion bulb change evident on sural nerve biopsy.

The relationship between nerve conduction velocity and sural nerve morphometric findings in HMSN type I and II

The relationship between nerve conduction velocity and sural nerve morphometric findings in HMSN type I and II

Neurographic follow-up study in HMSN type IV (Refsum's disease)

Neurographic follow-up study in HMSN type IV (Refsum's disease)

Ocular findings in Charcot-Marie-Tooth disease, HMSN type I

The ocular findings are described in nine patients with Charcot-Marie-Tooth muscular atrophy, who were also classified as suffering from Type I hereditary motor and sensory neuropathy on the basis of genetic, clinical and electromyographic studies. Although only three patients admitted to visual symptoms and all nine patients had full vision in both eyes, combined visual evoked potential and contrast sensitivity testing revealed optic nerve involvement in one or both eyes of seven patients. Four patients showed impaired accommodation and tonic pupils, and electroretinography revealed pigmentosa-like tracings in two patients. The high percentage of subclinical optic nerve lesions has not been previously reported; however, the remaining findings are in agreement with those of previous authors.