ObjectiveTo identify two pathogenic gene mutations in two families with Alström syndrome (ALMS). MethodsA retrospective clinical study. Two patients and five family members from two Han families of ALMS diagnosed at Henan Eye Hospital from August 2020 to December 2021 were enrolled in this study. All participants underwent comprehensive ophthalmic examinations including best corrected visual acuity (BCVA), color test, slit-lamp, fundus biomicroscopy with slit lamp, fundus color photography, optical coherence tomography (OCT) and full-field electroretinography (ff-ERG) after the detailed history of the patient was taken. Five millilitres peripheral venous blood of each subject was collected, and the whole genome DNA was extracted. The pathogenic genes and mutation sites were identified using whole exome sequencing and the identified mutations were verified by Sanger sequencing. Mutation sites were analyzed via bioinformatics softwares. ResultsFamily one included one victim and two members and family two included one victim and three members. Proband in the first family was a four-year old boy whose chief complaint was poor vision along with photophobia since born, while proband in the second family was a 12-year old girl whose chief complaint was the same. The boy proband could not distinguish color, and both the anterior segment and fundus were normal. Ellipsoid zone of the boy was unclear in both eyes in OCT, and though rod system function decreased mildly-moderately in both eyes, the cone system function decreased severely in ff-ERG. The girl could not distinguish color as well, and the anterior segment was normal, though obvious pigmentary change could be seen in both retinas. The integrity of outer retinal bands was unclear in both eyes in OCT, and both cone and rod systems function decreased severely in both eyes in ff-ERG. Gene tests and bioinformatics analyze showed c.468dupT and c.10819C>T of ALMS1 gene in family one were novel mutations and c.10819C>T in family one and c.10831_10832del in family two were pathogenic mutations. ConclusionsM1, M2 and M3, M4 may be pathogenic gene variants in family 1 and family 2, respectively. The compound heterozygous mutation, c.468dupT and c.10819C>T of ALMS1 gene was a novel mutation.
ObjectiveTo identify the pathogenic gene mutations in a family with Leber congenital amaurosis (LCA).MethodsIn October 2018, 1 patient and 3 normal family members from a LCA family was enrolled in this retrospective study. Detailed medical history of proband was obtained and fixation test, cycloplegic refraction, slit-lamp, fundus color photography and full-field ERG were performed. And other family members underwent BCVA, refraction slit-lamp, fundus biomicroscopy with the slit lamp, fundus color photography and full-field ERG. The family was investigated with a specific hereditary eye disease enrichment panel which contained 441 known pathogenic genes and based on targeted exome capture technology first to indentify the potential pathogenic genes and mutations. Then the potential pathogenic mutations were conformed by Sanger sequencing. Finally, the results were analyzed via bioinformatics analysis.ResultsThe proband showed no trace object from childhood, but had obvious photophobia and nystagmus. No positive changes were found in the anterior segment, vitreous and retina in both eyes. Both cone and rod system function decreased significantly in full-field ERG in both eyes. Gene tests showed the proband carried both RPGRIP1 c.1635dupA and c.3565C＞T, which composited a heterozygous mutation. Bioinformatics analysis showed RPGRIP1 c.1635dupA was a pathogenic mutation, and RPGRIP1 c.3565C＞T which was a novel potential pathogenic mutation in LCA.ConclusionThe compound heterozygous mutation, c.1635dupA and c.3565C＞T in RPGRIP1 may be responsible for the pathogenesis in this Chinese Han LCA pedigree.
ObjectiveTo identify the pathogenic gene mutations in a family with early onset severe retinal dystrophy (EOSRD).MethodsA retrospective clinical study. One patient and three family members from a Han of EOSRD who were diagnosed at Henan Eye Hospital in August 2018 were included in the study. After the detailed history of the patients was collected, all participants underwent best corrected visual acuity (BCVA), slit-lamp, fundus biomicroscopy with the slit lamp, untra-widefield fundus color photography, spectral-domain optical coherence tomography (SD-OCT) and full-field electroretinography (ff-ERG). The subject’s peripheral venous blood of 5 ml was collected and the whole genome DNA was extracted. A genetic eye disease capture chip containing 441 disease-causing genes was used for targeted capture and enrichment of high-throughput sequencing, and Sanger sequencing was performed for the clear pathogenic mutation sites; the analysis software was used for bioinformatics analysis of the mutation sites.ResultsA 6-year-old female proband developed poor night vision in both eyes after 1 year old. The BCVA of both eyes were 0.1. The color of the optic disc was slightly lighter; the diameter of the retinal vessels was slightly reduced, and extensive pigment changes can be seen in the retina outside the vascular arch. SD-OCT examination showed that the outer membrane, ellipsoid zone and chimera zone in the central fovea of both eyes were unclear and intermittent. The visual area outside the fovea was neuroepithelial outer plexiform layer, outer nuclear layer, outer membrane, ellipsoid zone. The chimera zone gradually disappeared, and the thickness of the pigment epithelial layer was not uniform. In ff-ERG examination, the functions of the binocular cone and rod system were severely decreased. The results of genetic testing showed that there were c.921C>A homozygous mutations in the Tubby-like protein (TULP1) gene of the proband, and c.3121C>T and c.3488G>A compound heterozygous mutations in the cyclic nucleotide gated channel beta 1 (CNGB1) gene. Amino acid conservation analysis results showed that the above three mutation sites were highly conserved in multiple species; bioinformatics analysis results showed that TULP1 gene c.921C>A (p.Cys307*) had translation termination in the protein conserved region, CNGB1 gene c.3121C>T (p.Arg1041Trp) and c.3488G>A (p.Gly1163Glu) had amino acid polarity changes in the protein conserved region, which led to major changes in the protein spatial structure.ConclusionTULP1 gene c.921C>A homozygous mutation, CNGB1 gene c.3121C>T and c.3488G>A compound heterozygous mutation are the mutation sites of this EOSRD family.
ObjectiveTo determine the pathogenic gene mutation in a family with incomplete congenital quiescent night blindness (CSNB) of Schubert-Bornschein type. MethodsA retrospective clinical study. In February 2021, one patient and his parents and elder brother from a Han Chinese incomplete CSNB of Schubert-Bornschein type family diagnosed by clinical and genetic examination at Henan Provincial People's Hospital were included in the study. The patient’s medical history, family history were inquired; best corrected visual acuity (BCVA), color vision, fundus color photography, full-field electroretinogram (ERG), and frequency domain optical coherence tomography (OCT) were examined in detail. Five ml of the subject’s peripheral venous blood was collected and the whole genome DNA was extracted. The genomic DNA of the subject was library constructed, and all-exon probes were polymerized for capture. The suspected pathogenic mutation site was verified by Sanger, and the pathogenicity of the gene mutation site was determined by parallel bioinformatics analysis. ResultsThe BCVA of both eyes of the proband (Ⅱ2) was 0.4; the color vision test could not recognize the red color. Fundus examination showed no obvious abnormalities. The retina thickness in the macular area of both eyes was slightly thinned. ERG examination of the whole field showed that the amplitude of ERG b wave was significantly reduced under the stimulation of binocular dark adaptation 3.0 and showed a negative waveform. The mother of the proband (Ⅰ2) had normal BCVA, color vision, fundus color photography, and frequency domain OCT examination. The full-field ERG examination showed that the amplitude of each eye reaction was slightly reduced, and the amplitude of the dark adaptation shock potential was significantly reduced. Genetic testing showed that the proband (Ⅱ2) had a c.1761dupC hemizygous mutation in exon 14 of the voltage-dependent calcium channel α1F subunit gene (CACNA1F gene). The results of protein sequence homology analysis showed that the site was highly conserved in multiple species; the results of bioinformatics analysis showed that the CACNA1F gene c.1761dupC (pY588fs) subsequently had a frameshift mutation and became a stop at position 10. Codons appear translational termination in the conserved regions of the protein. According to the standards and guidelines of the American College of Medical Genetics and Genomics, the mutation was judged to be a possible pathogenic variant. The mother of the proband (Ⅰ2) was a carrier of this site mutation. The clinical and genetic test results of the father and elder brother of the proband were not abnormal. ConclusionCACNA1F gene c.1761dupC is the pathogenic mutation site of the Schubert-Bornschein type incomplete CSNB family.