Screening for mutations in the IMPDH1 gene in Japanese patients with autosomal dominant retinitis pigmentosa.
OBJECTIVE
To determine the presence and frequency of mutations in the IMPDH1 gene in Japanese patients with autosomal dominant retinitis pigmentosa (ADRP), and to characterize the clinical characteristics of patients with the Lys238Arg mutation in the IMPDH1 gene.


METHODS
Case reports and results of DNA analysis.


METHODS
All 14 coding exons of the IMPDH1 gene were directly sequenced in 96 unrelated patients with ADRP. The clinical features were determined by visual acuity, slit-lamp biomicroscopy, and kinetic visual field tests.


RESULTS
Two novel mutations, a Leu227Pro and Lys238Arg, in the IMPDH1 gene were identified in two unrelated families with ADRP. The clinical features associated with the Lys238Arg mutation were an early-onset and severe retinal degeneration.


CONCLUSIONS
The most commonly reported Asp226Asn mutation was not found in the Japanese population, instead two novel mutations were found. These findings suggest that mutations of the IMPDH1 gene cause ADRP in the Japanese population.
Wada
Yuko
Y
Department of Ophthalmology, Tohoku University School of Medicine, Sendai, Japan. yukow@oph.med.tohoku.ac.jp
Tada
Asako
A
Itabashi
Toshitaka
T
Kawamura
Miyuki
M
Sato
Hajime
H
Tamai
Makoto
M
D000328:Adult; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005260:Female; D005799:Genes, Dominant; D005820:Genetic Testing; D006801:Humans; D007168:IMP Dehydrogenase / Q000235:genetics*; D007564:Japan; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012174:Retinitis Pigmentosa / Q000208:ethnology / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014792:Visual Acuity; D014794:Visual Fields
D007168:IMP Dehydrogenase; C488211:IMPDH1 protein, human