Nanophthalmos is a congenital disorder, which is characterized by small eye without any ocular or systemic malformation. It has autosomal-dominant and recessive forms of inheritance. It manifests as reduced total axial length, high hyperopia and thickened sclera. Nanophthalmos is relatively rare, but at high risk of secondary angle-closure glaucoma, uveal effusion syndrome. It can be spontaneous remission or recurrent, and responses poorly to medication. The effect of systemic glucocorticoid treatment is not ideal. The surgery challenges with very high rate of intra- and post-operative complications such as hemorrhage, choroidal and retinal detachment, malignum glaucoma and uveal effusion, so that the prognosis is poor. It is of great instructive significance to further understand the clinical features, complications and treatment progress and to avoid the missed diagnosis and misdiagnosisi of its complications, and thus choose the right management.
ObjectiveTo identify the causative genes of the posterior microphthalmia-retinal pigment degeneration family. MethodsA retrospective clinical study. One child (proband) and 3 family members of a family with posterior microphthalmia-retinitis pigmentosa diagnosed by clinical and genetic examination at Henan Provincial People's Hospital in July 2019 were included in the study. Medical history and family history, and draw pedigree of the patients was collected. Visual acuity, visual field, fundus color photography, optical coherence tomography and electroretinogram (ERG) were examined. The peripheral venous blood of the proband, his parents and sister, and extract the whole genome DNA was collected. Whole-exome sequencing was used to detect genetic variations, the suspected pathogenic variations were verified by Sanger sequencing, and the pathogenicity was determined by bioinformatics analysis. ResultsThe parents discovered the proband was poor vision at the age of 10 months. At the age of 3, the best corrected visual acuity of the right eye and the left eye were 0.3 and 0.4, respectively. No abnormality was found in anterior segment. Extremely high hyperopia in both eyes. The axial length was 14.47 mm and 15.78 mm, respectively. The optic disc of both eyes was relatively small and flushed, retinal folds can be observed in macular area, and no obvious pigment deposition was found. ERG examination showed that the rod system response and the maximal combined response of both eyes decreased slightly to moderately, and the single-flash cone response and the 30 Hz flicker response decreased moderately to severely. Genetic analysis revealed two novel mutations in the membrane frizzled-related protein (MFRP) gene in the proband: c.363delC/p.Thr121Thrfs*16, c.1627C＞T/p .Gln543Stop,37 in exon 4 and 13, the former was a frameshift mutation, encoding 16 amino acids and then terminated, and the latter was an nonsense mutation, truncated 37 amino acids, both which were predicted to be pathogenic and segregate with disease. The mother and sister carried c.363delC, and the father carried c.1627C＞T. ConclusionMFRP gene c.363delC/p.Thr121Thrfs*16, c.1627C＞T/p.Gln543Stop, 37 compound heterozygous mutation may be the pathogenic gene of this family.