Objective To investigate the genotype and phenotype in patients with leber congenital amaurosis (LCA), and offer accurate genetic counseling and prenatal diagnosis for those families. Methods Three LCA patients and their parents were recruited for this study and received detailed collection of medical history and family history from March to August 2016. The three patients received fundus fluorescein angiography examination and their parents received slit-lamp microscope and indirect ophthalmoscopy examinations. DNA was extracted from the patients and their family members. Whole-exome sequencing method was used for genetic diagnosis and typing of the three LCA patients and their parents. Results The three patients with different clinical features had a definite clinical diagnosis of LCA. Patient 1 showed pale disc, attenuated vessels aroud the optic disc and the salt-and-pepper appearance of the retina, had the homozygous c.744.745insT (p.249, L>Ffs4) mutation inSPATA7. Patient 2 showed optic disc pallor and attenuated retinal vessels, had the heterozygous c.535G>A, p.A179T mutation inWFS1. Patient 3 showed pale disc, atrophic macular and retinal and choroidal degeneration, had the heterozygous mutation in CRB1, RPGRIP1, SPATA7. Conclusion LCA has characteristics of genetic heterogeneity and clinical and phenotypic diversity.
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.
Cilia are hair-like protuberance on cells of the human body that play a vital role in organs generation and maintenance. Abnormalities of ciliary structure and function affect almost every system of the body, such as the brain, eyes, liver, kidney, bone, reproductive system and so on. Retinal photoreceptor cells are one of sensory neurons which convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, and disruptions in cilia genes, which are causative in a growing number of non-syndromic retinal dystrophies, such as retinitis pigmentosa, Leber’s congenital amaurosis. These syndromes are genetically heterogeneous, involving mutations in a large number of genes. They show considerable clinical and genetic overlap. At present, there are few researches on retinal ciliopathies and clinical treatment strategy. This review shows a comprehensive overview of ciliary dysfunction and visual development related diseases, which contributes to understand the characteristics of these diseases and take early intervention in clinic.
ObjectiveTo observe and analyze the pathogenic gene types and clinical phenotypes of Leber congenital amaurosis (LCA).MethodsA retrospective clinical study. Six patients with LCA confirmed by genetic testing and 18 family members were included in the study. The patients came from six unrelated families. The family was investigated with a specific hereditary eye disease enrichment panel which contained 463 known pathogenic genes and based on targeted exome capture technology first to indentify the potential pathogenic genes and mutations. Then the TULP1, RPGRIP1, GUCY2D pathogenic mutations were conformed by Sanger sequencing. The pathogenicity of the gene variation was searched through relevant databases and PubMed literature, and its function was explained by protein prediction software.ResultsOf the 6 patients, 3 were males and 3 were females; the age was from 3 to 33 years. Nystagmus, finger pressing eyes, photophobia, and night blindness were seen in 5 cases; electroretinogram showed 3 cases of extinction or near extinction; and 4 cases of retinopathy. The results showed patients with compound heterozygous mutation of c.1318C＞T and c.1142T＞G, homozygous mutation ofc.1318C＞T and compound heterozygous mutation of c.1153G＞A and c.1561C＞T of TULP1 in Family 1, Family 2 and Family 5, respectively. There were compound heterozygous mutations of RPGRIP1 c.391delG and c.1468-2A＞G in Family 3 and c.715delA and c.1765C＞T in Family 6, respectively. Homozygous mutation of c.3177_3178delAC of GUCY2D was found in Family 4.The parents of all six patients were carriers of corresponding heterozygous mutations.TULP1 gene c.1142T＞G, RPGRIP1 gene c.391delG, c.715delA and c.1765C＞T and GUCY2D gene c.3177_3178delAC mutations were novel mutations and unreported. The 381th amino acid locus of product protein of TULP1 gene was highly conserved among species. The protein prediction software predicted that the mutation pathogenic. The c.391delG, c.715delA and c.1765C＞T mutations of RPGRIP1 gene and c.3177_3178delAC mutation of GUCY2D gene can lead to early translation termination of their product proteins, which are pathogenic variants.ConclusionThe pathogenic mutations of TULP1, RPGRIP1 and GUCY2D genes led to LCA 15, LCA 6 and LCA 1 in six families.
ObjectiveTo investigate the relationship between genotype and phenotype in children with CRB1 mutated Leber congenital amaurosis (LCA) and early onset retinal dystrophy (EOSRD).MethodsA retrospective clinical study. From January 2013 to December 2019, 10 children with CRB1 mutated LCA/EOSRD were enrolled in the study. The patients were identified as CRB1 mutation by the second generation targeted capture sequencing, Sanger sequencing and the family segregation analysis. All children underwent electroretinogram (ERG) and fundus examination. At the same time, 6 cases were examined by optical coherence tomography (OCT); 1 case was examined by fluorescein fundus angiography (FFA), 7 cases were examined by wide-angle laser scanning ophthalmoscope (UWF SLO).ResultsThere were 6 cases of LCA and 4 cases of EOSRD in 10 patients with CRB1 gene mutations. The average age of first visit was 3.61 years old. The light and dark wave of ERG was flat in 6 cases, and decreased in 4 cases. A total of 19 pathogenic mutations were detected. There were 1 homozygous mutation and 9 compound heterozygous mutations. There were 4, 2 and 1 cases of “copper-coin” like, “salt and pepper” like and “osteocyte” like pigment changes in retina, 1 case of “crystalline pigment” change and 2 cases of macular pigment scar. In 7 cases of UWF SLO examination, different degrees of para-arteriolar pigment epithelium retention (PPRPE) were found in the middle and peripheral fundus. In 6 cases examined by OCT, the outer layer of retina atrophied and the band of ellipsoid disappeared. Symmetrical cystoid macular edema, splitting cystoid macular degeneration and adhesion of epi-macular membrane to optic disc and macular area were found in 1 case, respectively, the retinal structure was rough and thickened, and the fovea became thinner in 3 cases. In FFA examination, 1 case showed uveitis-like changes with late optic disc fluorescein staining, macular fluorescence accumulation, strong fluorescence diffusing along the blood vessels in each quadrant, peripheral PPRPE of “frost-branch” like strong fluorescence.ConclusionThe relationship between genotype and phenotype of CRB1 mutation is complex, and PPRPE is a common characteristic change.
ObjectiveTo observe clinical phenotypes and analyze the pathogenic genes of Leber congenital amaurosis (LCA). MethodsA retrospective clinical study. From 2019 to 2020, 2 patients diagnosed with LCA by genetic testing in Tianjin Medical University Eye Hospital and their 6 unaffected family members were enrolled in the study. Two patients were from 2 unrelated families, both were probands. The patient's medical history was inquired in detail, slit lamp microscopy, ultra-widefield fundus photography, autofluorescence, and flash visual evoked potential (F-VEP) were performed. Peripheral vein blood (3-5 ml) was collected and genomic DNA was extracted from all study subjects. A total of 381 pathogetic genes associated with inherited retinal diseases, were selected by targeted exome sequencing capture strategy. Sanger sequencing was used to verify suspected pathogenic mutations. Candidate pathogenic mutations were identified after bioinformatics analysis. Sanger sequencing, real-time quantitative polymerase chain reaction and family co-identification were used to confirm the final mutations. ResultsTwo patients were male, aged 3 and 27 years. One case had vision loss in both eyes, accompanied by nystagmus and acupressure eye sign since childhood. The clinical hallmark of the proband (F1-Ⅱ-3) in F1 includes clearly boundary of optic disc, normal retinal blood vessels and macular fovea. The implied period of the maximum forward wave in both eyes of F-VEP was roughly normal, and its amplitude decreased significantly. The phenotype of the proband (F2-Ⅱ-1) in F2 includes optic nerve head pallor, bone-spicule intraretinal pigmentation, “gold-foil maculopathy”, retina patchy hypo-autofluorescence in both eyes. There was no abnormal phenotype in the eyes of the family members. According to the genetic diagnosis, the proband (F1-Ⅱ-3) carried the GUCY2D gene c.835G>A (p.D279N) (M1) and exon 9-19 deletion (M2) compound heterozygous mutations, in which M1 was derived from healthy mother and M2 was derived from healthy father. The proband (F2-Ⅱ-1) carried CRB1 gene c.1576C>T(R526X) (M3) and c.1522T>C (C508R) (M4) compound heterozygous mutations, in which M3 from the healthy father, M4 from the healthy mother. M2 and M4 were novel mutations. ConclusionGUCY2D gene mutations lead to LCA1 type in the F1 family, CRB1 gene mutations lead to LCA8 type in the F2 family; there are significant different phenotypes caused by different pathogenic genes.
ObjectiveTo identify 3 the disease-causing genes and mutations of Leber congenital amaurosis (LCA), and to study the correlation of phenotype and genotype. MethodsA retrospective study. Four LCA patients and seven family members who were diagnosed by eye examination in Ning Xia Eye Hospital of People's Hospital of Ningxia Hui Autonomous Region from January to December 2021 were included in the study. Four patients were from 3 unrelated families. Detailed collection of medical history and family history were received. Related ophthalmologic examination were collected and genomic DNA was extracted from peripheral blood. Whole-exome sequencing method was used for genetic diagnosis. The identified variant was confirmed with Sanger sequencing. Potential pathogenic mutation was analyzed using software and conserved domain analysis and performed co-separated analysis between the family member and the proband. ResultsOf the 4 patients, 1 patient was males and 3 patients were females; the age was from 4 to 18 years. Nystagmus were seen in 3 cases, finger pressing eyes and night blindness was seen in 1 cases; electroretinogram showed 4 cases of extinction or near extinction. The foveal reflection was visible in all eyes, and there was no obvious abnormality in the peripheral retina. One eye had strong reflection signal with raised ellipsoid in macular area; two eyes had weak reflection signal faintly visible between retinal layers; 1 eye had increased blood vessel branches, peripheral retinal non-perfusion area with capillary leakage; annular strong autofluorescence in macular area 4 eyes. No obvious abnormality was found in the phenotypes of family members. Genetic testing showed that the proband of pedigree 1 (Ⅱ-1) was found a homozygous missense mutation in c.640A>T (p.C214S) (M1) of PRPH2 gene. The proband of pedigree 2 (Ⅱ-2) was found compound heterozygous mutation in c.1256G>A(p.R419Q) (M2) and c.1A>C (p.M1L) (M3) of TULP1 gene. The proband 3 (Ⅱ-1) and her sister (Ⅱ-2) were both found compound heterozygous mutation in c.1943T>C (p.L648P) (M4) and c.380C>T (p.P127L) (M5) of GUCY2D gene. The parents and sister (Ⅱ-1) of the proband in family 2 and the parents of the proband in family 3 were all carriers of the corresponding heterozygous variant. M1, M3, M4, M5 were novel mutations and unreported. The genotype and disease phenotype were co-segregated within the family. According to the analysis of pedigree and genetic testing results, all 3 families were autosomal recessive inheritance. The amino acid conservation analysis found that M1, M2, M3, M4, and M5 were highly conserved among species. The results of bioinformatics analysis were all pathogenic variants. ConclusionsPRPH2 gene M1, TULP1 gene M3, and GUCY2D gene M4, M5 were novel mutations and not been reported in the literature and database. This research expanded the gene mutation spectrum of LCA. The patients with LCA have available characterristics, including onset age, varying ocular fundus and severe visual impairment.
ObjectiveTo identify and observe disease-causing gene variants and clinical phenotypes in a Han Chinese family with Leber congenital amaurosis (LCA). MethodsA retrospective study. A patient with LCA10 and his parents who had presented at Department of Ophthalmology of Henan Provincial People's Hospital on May 2022 were selected as the study subject. Detailed medical and family histories were recorded, fundus photography and flash electroretinogram (F-ERG) were performed. Peripheral venous blood samples (3 ml) of the proband and his parents were collected to extract whole genomic DNA, then whole exome sequencing (WES) and mitochondrial DNA (mtDNA) sequencing were carried out for the proband to determine the disease-causing gene and variants. All variants were annotated by bioinformatics analysis. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, the pathogenicity of all detected variants were evaluated. Candidate variants were verified by Sanger sequencing, and in vitro minigene assay were performed to evaluate the impact of the missense variant with insufficient evidence on mRNA splicing. ResultsThe proband, male, 7-month-old, presented with an inability to follow light or objects, eye poking, photophobia, nystagmus, partial loss of retinal pigment epithelium around the fovea of the macula. At the age of 2 years old, F-ERG revealed severe reduction, elongation, or even no waveform of a-wave and b-wave in both eyes. No obvious abnormality was found in the clinical phenotype of his parents. The result of WES revealed that the proband carried two variants in exon 40 and exon 2 of CEP290, a frameshift variant c.5515_5518del (p.Glu1839Lysfs*11) (V1) and a novel missense variant c.74C>T (p.Ala25Val) (V2), respectively. The result of mitochondrial DNA sequencing was negative. Sanger sequencing confirmed that the heterozygous frameshift variant was inherited from his father and the heterozygous novel missense variant was inherited from his mother, which constituted compound heterozygous variants. In vitro minigene splicing assay confirmed that V2 created a new splicing donor at exon 2, leading to the in-frame deletion of 30bp fragment during transcription and loss of 10 amino acid residues in the protein. The two variants were pathogenic (V1) and likely pathogenic (V2) based on ACMG guidelines, respectively. ConclusionsThe c.5515_5518del and novel c.74C>T compound heterozygous variants of the CEP290 gene probably are the cause of LCA10 in this family, which lead to the production of a truncated protein and aberrant splicing of pre-mRNA, respectively. LCA is characterized by early onset, severe impairment of visual function, and a wide range of disease-causing variations.