Abstract
Purpose::
To describe clinical and genetic characteristics of a Japanese family with microphathalmia, cataract, and the absence of pupil formation, which seemingly exhibited autosomal dominant mode of inheritance.
Methods::
Ocular examinations including slit-lamp microscopy, ultrasonography and utralsound biomicroscopy were performed in four patients within the three-generational family. A possible involvement of genes known to be related to either microphthalmia or anterior segment anomalies (CHX10, EYA1, FOXC1, GJA1, MAF, PAX6, SOX2, SOX11) was tested. Thirteen di-nucleotide repeats tightly linked to these genes were identified from the human genome sequence and used as markers in amplification and genotyping, followed by linkage analysis for seven members of the family.
Results::
Three affected members (one-year-old girl, five-year-old boy, and 34-year-old father) exhibited a uniform phenotype including no pupil formation with poorly developed iris stroma, calicified crystalline lens and microphthalmia bilaterally. The pupils were surgically constructed in four eyes of the siblings while the father remained to be untreated. Postoperatively the retina was found to be well developed in all treated eyes altough a total retinal detachment developed subsequenctly in one eye. The best-corrected visual acuities ranged from light perception to 0.2. A 65-year-old paternal grandmother had bilateral microphthalmia which become phthesical in the third decade. Genetic examination indicated that only one of eight genes (MAF) segregated concordantly with the disease.
Conclusions::
This is an ongoing project, and other genes interested are being searched for the segregation pattern. Exclusion of known genes related to these ocular conditions may help to identify disease-causing gene. The understanding of the pathogenesis of this disease will offer to proper genetic counseling.
Keywords: development • genetics • iris