Mutations in the XLRS1 gene in Thai families with X-linked juvenile retinoschisis.
OBJECTIVE
To identify genetic mutations of the XLRS1 gene and to describe the ocular phenotypes in two unrelated Thai patients with X-linked juvenile retinoschisis.


METHODS
Ophthalmic examination, including best-corrected visual acuity and fundus examination and photography, was performed in all participants. Electroretinography (ERG) and optical coherence tomography were performed when possible. All six exons of the XLRS1 gene were amplified, and mutation screening was determined by denaturing high-performance liquid chromatography and DNA sequencing.


RESULTS
Two point mutations were identified, a novel missense mutation c.378A > G (p.D126G) in exon 5 and a reported mutation c.637C > T (p.R213W) in exon 6. The first proband with the p.D126G mutation developed vitreous hemorrhage in both eyes at age 7 months. Foveal and peripheral schisis with several inner layer holes were detected in both eyes. The second proband with the p.R213W mutation developed slightly blurred vision at age 10 years. Fundus examination showed numerous fine white dots at the macula without foveal or peripheral schisis. Electronegative ERG results were documented in both probands.


CONCLUSIONS
A novel p.D126G mutation appeared to be associated with a severe phenotype with vitreous hemorrhage developing in infancy. Both intra- and interfamilial clinical variabilities were recognized in our patients.
Atchaneeyasakul
La-ongsri
LO
Department of Ophthalmology, Siriraj Hospital Mahidol University, Bangkok, Thailand. atchanee@hotmail.com
Trinavarat
Adisak
A
Pituksung
Auengporn
A
Jinda
Worapoj
W
Thongnoppakhun
Wanna
W
Limwongse
Chanin
C
D000328:Adult; D044466:Asian People / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005091:Exons / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D041441:Retinoschisis / Q000175:diagnosis / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013785:Thailand; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D014823:Vitreous Hemorrhage / Q000235:genetics
D005136:Eye Proteins; C108726:RS1 protein, human