[Electrophysiological studies in siblings of De Sanctis-Cacchione syndrome].
Multi-modality evoked potentials in two cases, who were siblings, of De Sanctis-Cacchione syndrome were reported. The case 1, who was elder sister of the case 2, was a 25-year-old female. And the case 2 was a 23-year-old female. They have the history of consanguinity. They were first noted to have skin erythema on exposure to sunlight, and a diagnosis of xeroderma pigmentosum was made. At the childhood neurological manifestation, such as mental retardation, deafness and muscular weakness developed gradually. The case 2, who was a elder sister, was operated on for squamous cell carcinoma of the eyelid at the age of 20 and 21 years old. Motor conduction velocity obtained from lower limbs were severely reduced and that from upper limbs were moderately delayed. Sensory conduction velocity of median nerve were severely diminished. Auditory brainstem responses (ABR) of the case 1 showed the prolongation in interpeak latency of I-V. ABR of the case 2 could not be obtained. N19 and N13 of short-latency somatosensory evoked potentials (SSEP) to median nerve stimulation with case 2 could not be obtained too. N13-N19 latency of case 1 was remarkably prolonged compared to the normal subjects. Central motor conduction time (CMCT) was studied in case 2 by using the magnetic stimulator. CMCT of case 2 was within the upper limit of normal control. Interpeak latency of I-V in ABR represents the brainstem dysfunction in auditory pathway, and interpeak latency of N13-N19 in SSEP was recognized as central conduction time from medial lemniscus to primary sensory area of cortex. So the prolongation of these interpeak latency in this cases may mean the dysfunction in the central nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)