Author/Editor		Butinar, Dušan; Starr, Arnold; Zidar, Janez; Koutsou, P.; Christodoulou, K.
Title		Auditory nerve is affected in one of two different point mutations of the neurofilament light gene
Type		članek
Source		Clin Neurophysiol
Vol. and No.		Letnik 119, št. 2
Publication year		2008
Volume		str. 367-75
Language		eng
Abstract		Objective: To define auditory nerve and cochlear functions in two families with autosomal dominant axonal Charcot-Marie-Tooth (CMT). Methods: Affected members in two families with different point mutations of NF-L gene were screened with auditory brainstem responses (ABRs). Those with abnormal ABRs were further investigated with clinical, neurophysiological and audiological procedures. The point mutations of NF-L gene involved were Glu397Lys in 8 affected members of the family with AN, and Pro22Ser in 9 affected members of the family without AN. Results: ABRs and stapedial muscle reflexes were absentor abnormal in affected members of only one family consistent with auditory neuropathy (AN). In them, audiograms, otoacoustic emissions, and speech comprehension were normal. Absent or abnormal ABRs were consistent withslowing of conduction along auditory nerve andžor brainstem auditory pathway. Wave I when present was of normal latency. Conclusions: Auditory nerve involvement in the presence of normal cochlear outer hair cell activity is asymptomatic in one of two families with CMT disorder with different point mutations of the NF-L gene. The nerve disorder is consistent with altered synchrony and slowed conduction. Significance: The absence of deafness may reflect the ability of central mechanisms to compensate for the slowly developing auditory nerve abnormalities.
Descriptors		COCHLEAR NERVE CHARCOT-MARIE DISEASE POINT MUTATION EVOKED POTENTIALS, AUDITORY, BRAIN STEM AUDIOMETRY VESTIBULAR FUNCTION TESTS EVOKED POTENTIALS, MOTOR