H-reflex studies in a family with possibly X-linked neuronal Charcot-Marie-Tooth disease.

The neuronal type of Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathy, type II) was found to be present in ten of thirty-two members of one family. Motor nerve conduction velocities in this type of the disease may be normal in persons who are only mildly affected. Hoffmann-reflex investigation was effective in discriminating between affected and non-affected subjects. The mode of inheritance seemed to be X-linked, but this remained doubtful, because the outcome of the Hoffmann-reflex investigations was abnormal in one clinically non-affected boy. Xg(a)-typing gave no information as to linkage with the gene-locus of CMT. Close linkage between the loci for deutan anomaly and for CMT appeared to be very unlikely.