Abstract
Purpose: :
Nanophthalmos is the leading cause of blindness in hereditary eye diseases, which is an uncommon developmental ocular disorder characterized by a small eye. The purpose of this study was to investigate the genetic, pathologic and clinical features in Chinese nanophthalmos patients, and to evaluate the effect of surgical treatment of nanophthalmos with complication.
Methods: :
70 eyes of 35 patients(14 patients from 6 pedigrees and 21 sporadic patients) with nanophthalmos were studied between 1995 and 2000, 200 normal eyes(100 persons) were included as control. The CHX10 and RAX(retinal homeobox) genes were screened by PCR (polymerase chain reaction) and sequencing analysis. A series of ocular parameters were measured with ultrasound A-scan, ultrasoundbiomicroscopy and dioptometry. 51 nanophthalmos eyes complicated with exudative retinal detachment(17 eyes), uveal effusion(39 eyes) and/or glaucoma(25 eyes) during the progressive stage were treated by improved sclerectomy and sclerotomy, and the effect of treatment were followed up for 5 years. Pathologic characters of the excised sclera were analyzed by immunohistochemical and electron microscopic examinations.
Results: :
Nanophthalmos is characterized with short ocular axial length (15.95±0.76mm), thick sclera (0.917±0.119mm) and ciliary body, and crowded anterior chamber. The cure rate of complication after the surgical treatment were as followed, exudative retinal detachment (94.1%), uveal effusion (97.4%) and ocular hypertension (90.0%). The collagen fiber bundles are irregularly arranged and separated into small fibrils, and glycogen granules were found accumulated between the twisting or fraying collagen fibrils in sclera of nanophthalmos. 3 SNPs (single nucleotide polymorphism) were found in CHX10 gene, of which 2 SNPs were first reported in this study (g. 24396C>T in 9 cases; g.24142G>A, p.D291N in 1 cases). 2 SNPs were found in RAX gene (g. 928C>A in 14 cases; g. 4840A>G, p.Q294Q in 15 cases).
Conclusions: :
The developmental ocular disorder played important roles in the occurrence and development of nanophthalmos complication. The improved sclerectomy and sclerotomy was an effective surgical treatment for preventing and curing the complication and maintaining the remanet visual function of nanophthalmos. The nanophthalmos patients in this study may not be associated with mutation of CHX10 and RAX genes. The above novel SNPs expands the spectrum of CHX10 gene variations which would be useful for further genetic consultation and diagnosis.
Keywords: comparative anatomy • pathology: human • genetics