Bestrophin 1 gene analysis and associated clinical findings in a Chinese patient with Best vitelliform macular dystrophy

Multimodal imaging and genetic analysis of adult-onset best vitelliform macular dystrophy in Chinese patients

Compared to juvenile-onset best vitelliform macular dystrophy (BVMD), adult-onset BVMD is not well characterized and lacks strict diagnostic criteria. The present study aimed to evaluate the clinical and genetic characteristics of four advanced-age Chinese patients with adult-onset BVMD by combining multimodal imaging and genetic analysis. The four patients (all older than 50 years) were diagnosed with adult-onset BVMD at Zhongshan Ophthalmic Center (Guangzhou, China). Comprehensive ophthalmic examinations were performed, including analyses of best-corrected visual acuity, intraocular pressure, slit-lamp examination, fundus photography, optical coherence tomography, fundus fluorescein angiography and electrooculography. Genomic DNA was extracted from leukocytes isolated from peripheral blood obtained from these patients, their family members and 200 unrelated subjects from the same population. A total of 11 exons of the bestrophin-1 (BEST1) gene were amplified using PCR and sequenced. All of the four patients presented with lesions in the macular area. The patients were diagnosed with adult-onset BVMD based on multimodal imaging and genetic analysis. A total of four recurrent mutations, namely c.763C>T (p.Arg255Trp, p.R255W) in exon 7, c.584C>T (p.Ala195Val, p.A195V) in exon 5, c.910_912del GAT (p.304delAsp, p.D304del) in exon 8 and c.310G>C (p.Asp104His, p.D104H) in exon 4 of BEST1, were identified. Sorting intolerant from tolerant predicted that the amino acid substitutions p.R255W, p.A195V and p.D104H in the BEST1 protein were causing the damage. Combining multimodal imaging and genetic analysis was helpful in confirming the diagnosis of patients with adult-onset BVMD. These results maybe valuable for clinical and genetic counseling and for the development of therapeutic interventions for patients with BVMD.

A Case of Best Disease Accompanied by Pachychoroid Neovasculopathy

The aim of this case presentation is to describe ocular findings of a 22-year-old patient with Best vitelliform macular dystrophy accompanied by pachychoroid neovasculopathy. Color fundus photography, fundus autofluorescence (FAF), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) images were reviewed. Fundoscopic examination showed bilateral yellowish vitelliform-like submacular deposits. FAF revealed these deposits as hyperautofluorescent spots. OCT showed flat irregular pigment epithelial detachments corresponding to these submacular deposits. OCT showed choroidal thickening and dilatation of the large outer oval choroidal vessels. Fundus fluorescein angiography could not be performed because the patient was pregnant. En face OCTA images of the choriocapillaris illustrated the choroidal neovascular network. In this case report, we describe for the first time the coexistence of Best vitelliform macular dystrophy and pachychoroid neovasculopathy with OCTA images enabling visualization of the neovascular network in a patient with contraindication for fluorescein angiography.

Targeted next‑generation sequencing identifies two novel COL2A1 gene mutations in Stickler syndrome with bilateral retinal detachment

Stickler syndrome is a group of inherited connective tissue disorders characterized by distinctive facial and ocular abnormalities, hearing loss and early‑onset arthritis. The aim of the present study was to investigate the genetic changes in two Chinese patients with Stickler syndrome, manifested as bilateral retinal detachment and peripheral retinal degeneration. Complete ophthalmic examinations, including best‑corrected visual acuity, slit‑lamp examination and fundus examination, were performed. Genomic DNA was extracted from leukocytes of the peripheral blood collected from the patients, their unaffected family members and 200 unrelated control subjects from the same population. Next‑generation sequencing of established genes associated with ocular disease was performed. A heterozygous collagen type II α1 chain (COL2A1) mutation c.1310G>C (p.R437P) in exon 21 was identified in Family 1 and a heterozygous COL2A1 mutation c.2302‑1G>A in intron 34 was identified in Family 2. The functional effects of the mutations were assessed by polymorphism phenotyping (PolyPhen) and sorting intolerant from tolerant (SIFT) analysis. The c.1310G>C mutation was predicted to damage protein structure and function, and the c.2302‑1G>A mutation was predicted to result in a splicing defect. The findings of the current study expand the established mutation spectrum of COL2A1, and may facilitate genetic counseling and development of therapeutic strategies for patients with Stickler syndrome.

Clinical and next-generation sequencing findings in a Chinese family exhibiting severe familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary retinal disorder characterized by the premature arrest of vascularization in the peripheral retina. The aim of the present study was to characterize the clinical presentations of a Chinese family affected by bilateral severe FEVR, and to identify the underlying genetic variations. One family that presented with bilateral FEVR was recruited for this study. Comprehensive ophthalmic examinations, including best‑corrected visual acuity, slit‑lamp examination, fundus photography, fundus fluorescein angiography imaging and electroretinogram were performed. Genomic DNA was extracted from leukocytes of the peripheral blood collected from the affected and unaffected family members, as well as 200 unrelated control subjects from the same population. Next‑generation sequencing of the candidate genes associated with ocular diseases was performed, and the identified mutations were validated by conventional polymerase chain reaction‑based sequencing. The functional effects of the mutations were analyzed by polymorphism phenotyping (PolyPhen) and sorting intolerant from tolerant (SIFT). One heterozygous ATP binding cassette subfamily A member 4 (ABCA4) c.5693G>A (p.R1898H) mutation in exon 40 and one heterozygous LDL receptor related protein 5 (LRP5) c.260T>G (p.I87S) mutation in exon 2 were identified in this family. To the best of our knowledge, the ABCA4 c.5693G>A (p.R1898H) mutation has not been reported in FEVR, and the LRP5 c.260T>G (p.I87S) mutation is a novel mutation. PolyPhen and SIFT predicted that the amino acid substitution R1898H in protein ABCA4 is benign, whereas the amino acid substitution I87S in protein LRP5 is damaging. A single nucleotide polymorphism c.266A>G (p.Q89R, rs41494349) was identified in exon 2 of LRP5. These findings expand the mutation spectrums of ABCA4 and LRP5, and will be valuable for genetic counseling and development of therapeutic interventions for patients with FEVR.

Genetic variations in Bestrophin‑1 and associated clinical findings in two Chinese patients with juvenile‑onset and adult‑onset best vitelliform macular dystrophy

Best vitelliform macular dystrophy (BVMD) is a hereditary retinal disease characterized by the bilateral accumulation of large egg yolk‑like lesions in the sub‑retinal and sub‑retinal pigment epithelium spaces. Macular degeneration in BVMD can begin in childhood or adulthood. The variation in the age of onset is not clearly understood. The present study characterized the clinical characteristics of two Chinese patients with either juvenile‑onset BVMD or adult‑onset BVMD and investigated the underlying genetic variations. A 16‑year‑old male (Patient 1) was diagnosed with juvenile‑onset BVMD and a 43‑year‑old female (Patient 2) was diagnosed with adult‑onset BVMD. Comprehensive ophthalmic examinations were performed, including best‑corrected visual acuity, intraocular pressure, slit‑lamp examination, fundus photography, optical coherence tomography, fundus fluorescein angiography imaging and Espion electrophysiology. Genomic DNA was extracted from peripheral blood leukocytes collected from these patients, their family members, and 200 unrelated subjects within in the same population. The 11 exons of the bestrophin‑1 (BEST1) gene were amplified by polymerase chain reaction and directly sequenced. Both patients presented lesions in the macular area. In Patient 1, a heterozygous mutation c.903T>G (p.D301E) in exon 8 of the BEST1 gene was identified. This mutation was not present in any of the unaffected family members or the normal controls. Polymorphism phenotyping and the sorting intolerant from tolerant algorithm predicted that the amino acid substitution D301E in bestrophin‑1 protein was damaging. In Patient 2, a single nucleotide polymorphism c.1608C>T (p.T536T) in exon 10 of the BEST1 gene was identified. These findings expand the spectrum of BEST1 genetic variation and will be valuable for genetic counseling and the development of therapeutic interventions for patients with BVMD.