ObjectiveTo analyze and identify the pathogenic mutation that caused a case of child’s renal coloboma syndrome (RCS).MethodsA child with congenital cataract in the right eye and optic disc defect in the left eye and his parents with normal phenotype were included in the study. The blood of the child and his parents were captured to extract DNA and make molecular test. The possible variants were screened through NGS sequencing using the ophthalmology gene panel on illumina NextSeq 500 platform, and proved the selected PAX2 mutation by Sanger sequencing. Pathogenicity report was retrieved through PubMed and related database. Pathogenicity analysis of the candidate mutated site has careful consideration of the patient’s clinical presentations and sequencing result base on Standards and Guidelines for the Interpretation of Sequence Variants revised by ACMG. According to the results of gene diagnosis, the child was executed related clinical examinations on kidney.ResultsThe sequence result showed that a heterozygous mutation in PAX2, c.70dupG (p.V26Gfs*28), which lead to truncated protein product that terminated after 28 amino acids of the mutated site. Both of his normal parents were not carriers of the heterozygous mutation. Sanger sequencing results of the child and his parents were consistent with the NGS sequencing. The autosomal dominant disease phenotype was inferred to be caused by the heterozygous mutation of c.70dupG (p.V26Gfs*28) of PAX2 gene. Renal color Doppler ultrasound results showed the child with small renal cysts on the left and mildly separated collecting system. Renal function tests showed the child with α1 microglobulin index increased.ConclusionThe heterozygous mutation c.70dupG (p.V26Gfs*28) in PAX2 is the genetic pathogenic cause for the patient with RCS.
ObjectiveTo identify the pathogenic mutation in a patient with Oguchi disease.MethodsA Japanese patient with Oguchi disease was enrolled in this study, and underwent a comprehensive medical history assessment and multiple ophthalmic examinations, including BCVA, OCT, color fundus photography and full field electroretinogram. Genomic deoxyribonucleic acid (DNA) was extracted from peripheral blood samples for whole exome sequencing. The gene mutation was detected, and the analysis software was used to determine the conservation of the mutation and the possible structural changes.ResultsThe patient, 71 years old, with consanguineous parents, complained of night blindness since early childhood. BCVA in both eyes was 0.7 and the golden-yellowish reflex appeared in the grey retina. The scotopic 0.01 ERGs showed a extinguished reaction in both eyes. The scotopic 3.0 ERGs showed a “negative” configuration with a significantly reduced a wave and a nearly absent b wave. A homozygous deletion mutation in the SAG gene (c.924delA, p.N309Tfs*12) in this patient was founded by DNA sequencing, which was predicted to generate prematurely truncated SAG protein and result in severe structural change. Homology analysis of the protein sequence indicated that the mutation resulted in an altered amino acid which was evolutionarily highly conserved among different species, strongly suggesting the potential pathogenicity of this homozygous mutation.ConclusionThe mutation c.924delA(309Tfs*12) in SAG cause Oguchi disease in this patient.