[Mutation screening of MITF gene in patients with Waardenburg syndrome type 2].
Warrgenburg syndrome type 2 (WS2) is the most common autosomal dominantly-inherited syndrome with hearing loss. MITF (microphthalmia associated transcription factor)is a basic-helix-loop-helix-luecine zipper (bHLHZip) factor which regulates expression of tyrosinase, and is involved in melanocyte differentiation. Mutations in MITF associated with WS2 have been identified in some but not all affected families. Here, we report a three-generation Chinese family with a point mutation in the MITF gene causing WS2. The proband exhibits congenital severe sensorineural hearing loss, heterochromia iridis and facial freckles. One of family members manifests sensorineural deafness, and the other patients show premature greying or/and freckles. This mutation, heterozygous deletion c.639delA, creates a stop codon in exon 7 and is predicted to result in a truncated protein lacking normal interaction with its target DNA motif. This mutation is a novel mutation and the third case identified in exon 7 of MITF in WS2. Though there is only one base pair distance between this novel mutation and the other two documented cases and similar amino acids change, significant difference is seen in clinical phenotype, which suggests genetic background may play an important role.
Chen
Jing
J
Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, China E-mail: jingchen91@yahoo.com.cn.
Yang
Shu-Zhi
SZ
Liu
Jun
J
Han
Bing
B
Wang
Guo-Jian
GJ
Zhang
Xin
X
Kang
Dong-Yang
DY
Dai
Pu
P
Young
Wie-Yen
WY
Yuan
Hui-Jun
HJ
D000293:Adolescent; D000328:Adult; D002648:Child; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D008297:Male; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D014849:Waardenburg Syndrome / Q000235:genetics*; D055815:Young Adult
D051739:Microphthalmia-Associated Transcription Factor