A novel nonsense B3GALTL mutation confirms Peters plus syndrome in a patient with multiple malformations and Peters anomaly

Peters plus syndrome is an autosomal recessive rare congenital disorder defined by corneal Peters anomaly with short disproportionate stature, development delay and dysmorphic facial features. In addition, cardiac, genito-urinary and/or central nervous system malformations can be present. Mutations in the beta-1,3-galactosyltransferase-like glycosyltransferase gene (B3GALTL) have been reported in patients with Peters plus syndrome prompting phenotype-genotype studies because of the variable clinical spectrum related to the syndrome. A 20 month old boy presenting with bilateral Peters anomaly in association with multiple developmental anomalies including cerebral malformations was found to carry a novel homozygous B3GALTL nonsense mutation [p.Tyr366X]. This is the first stop mutation described in association with this gene. The present report confirms the wide clinical spectrum of Peters plus syndrome, underlines the major clinical criteria of the syndrome and the major implication of B3GALTL gene in this condition. Ophthalmologic examination in multiple developmental anomalies remains an important clinical issue that may lead to specific gene screening. In Peters plus syndrome B3GALTL molecular test provides diagnosis confirmation and improves dramatically genetic counselling for the families.     

Peters anomaly in association with multiple midline anomalies and a familial chromosome 4 inversion

We describe the clinical presentation of a boy with Peters anomaly and a cataract of the left eye in association with multiple midline defects. His extraocular developmental abnormalities include cleft lip and palate, cardiac anomalies, an atretic cranial meningocele, as well as malformation of the left ear with chronic otitis media. Genetic analysis revealed a balanced paracentric inversion of chromosome 4, inv(4)(q12q13.3), also present in his asymptomatic father and siblings. His normal stature and cognitive development distinguish this case from the Peters Plus syndrome. The presence of a cranial meningocele represents a new association with Peters anomaly.     

A novel nonsense mutation with a compound heterozygous mutation in TGFBI gene in lattice corneal dystrophy type I

PURPOSE: We examined transforming growth factor beta-induced (TGFBI) gene mutations in a family with lattice corneal dystrophy type I. METHODS: The proband was one of the offspring of a consanguineous marriage; 4 affected and 3 unaffected individuals of the family were investigated. Genomic DNA of each case was extracted and used for polymerase chain reaction (PCR). The exon 4, 11, and 12 of the TGFBI gene were directly sequenced. The mutations were confirmed by PCR restriction fragment length polymorphism analysis. RESULTS: There was no significant difference in phenotype between the proband and the other 2 patients, except for progression of the corneal opacity with age. R124C mutation was detected in all affected individuals. In addition, G470X, a novel nonsense mutation, was detected in the proband, resulting in the proband being a compound heterozygote with the TGFBI gene. Her unaffected daughter was found to be heterozygous for G470X. CONCLUSION: It is most likely that the novel nonsense mutation is not pathogenic, and that the mutant keratoepithelin protein with R124C is responsible for the phenotype.     

A new novel nonsense mutation in AIPL1 in a LCA4 family

ABSTRACT

Purpose: To investigate the disease-causing gene in a Chinese family with Leber congenital amaurosis 4 (LCA4).

Materials and methods: Four members of an LCA family underwent ophthalmological examination and systemic assessment. DNA samples were obtained from their peripheral blood. Whole exome sequencing (WES) was performed in the two patients. After data filtering, Sanger sequencing was performed to verify the mutation within this family.

Results: The two patients were diagnosed as having LCA4 and with keratoconus (KCN). The older brother also has intellectual disability, epilepsy, Tourette syndrome and an abnormal gait, while the younger one has an abnormal bulge at the end of his sternum. A novel p.Gln81* mutation in the AIPL1 gene was determined as causing LCA4 in this family. Protein structure change prediction showed AIPL1 p.Gln81* mutation coded a very short AIPL1 peptide and could not form a normal structure as an normal AIPL1 protein.

Conclusion: Although KCN has been associated with LCA4, this type of LCA is typically moderate in severity and variable between patients. The present cases also have some systemic abnormalities.     

A novel mutation confirms MFRP as the gene causing the syndrome of nanophthalmos-renititis pigmentosa-foveoschisis-optic disk drusen

PURPOSE: To describe the clinical and genetic characteristics of the second family with a recently described recessive syndrome characterized by posterior microphthalmos, retinitis pigmentosa, foveoschisis, and optic disk drusen. DESIGN: Observational case report. METHODS: Three affected subjects and one healthy sibling from a consanguineous marriage from Spain were studied. Complete ophthalmologic examinations including A- and B-mode ultrasonography (US), electroretinography (ERG), fluorescein retinal angiography (FA), and optical coherence tomography (OCT) were performed in each individual. Genetic analysis included polymerase chain reaction amplification and direct nucleotide sequencing of the complete MFRP gene. RESULTS: All three affected siblings had bilateral shortening of the posterior ocular segment associated with high hyperopia and normal anterior segment dimensions. Best-corrected visual acuity ranged from 20/200 to 20/60. Funduscopy, ERG, and FA were compatible with retinitis pigmentosa, and B-mode ultrasound showed optic disk drusen. OCT analysis revealed outer retinal layer schisis with absence of foveal pit. Inheritance of this syndrome followed an autosomal recessive pattern. Molecular analysis revealed a novel homozygous 1-bp deletion (c.498delC) in exon 5 of MFRP, predicting a prematurely truncated protein (P166fsX190). A healthy sister demonstrated to be a carrier of the mutation. CONCLUSIONS: We confirmed that the syndrome of posterior microphthalmos, retinitis pigmentosa, foveoschisis, and optic disk drusen constitutes a distinct autosomal recessive entity. The novel frameshift mutation identified in the family described here validates MFRP as the gene responsible for this particular disease, which characteristically involves structures located at the posterior segment of the eye.     

A deletion mutation along with a novel DNA variation in OCRL cause Lowe syndrome in a child with multiple secondary manifestations

Dear Editor,We report the deletion and insertion mutations of oculocerebrorenal syndrome of Lowe(OCRL)in a child who has been presenting typical symptoms of Lowe syndrome with many secondary phenotypes including dental abnormalities,bleeding problems,mild hypochromic anemia.     

Enhanced S-cone syndrome in a Japanese family with a nonsense NR2E3 mutation (Q350X)

PURPOSE: To describe the clinical characteristics of a Japanese male patient with enhanced S-cone syndrome (ESCS) and investigate the existence of mutations in the NR2E3 gene, which encodes a photoreceptor cell-specific nuclear receptor. METHODS: Fundus examinations, fluorescein angiography, colour vision tests, spectral sensitivity, and full-field and spectral electroretinography were performed. Mutation screening of the NR2E3 gene was performed with polymerase chain reaction (PCR) amplification and direct sequencing. RESULTS: We identified a novel homozygous mutation (c.1048C > T), that converts glutamine (CAA) to a termination codon (TAA) at amino acid position 350. The subject's unaffected parents were heterozygous for the mutation, consistent with autosomal recessive transmission. The electroretinographic findings revealed that the patient had neither rod nor 30-Hz flicker responses but did have cone responses with large a-wave and low b-wave amplitudes, similar to the rod-plus-cone responses, and also substantial short wavelength-sensitive (S) cone and extremely diminished long/middle wavelength-sensitive (L/M) cone responses. In the right eye, spectral sensitivity in the fovea revealed both functional S-cone and remarkably reduced L- and M-cone sensitivities, which was compatible with the decreased visual acuity (VA) and red/green colour vision defects noted in this eye. In contrast, the patient had good VA and normal red/green colour vision in the left eye. CONCLUSION: The nonsense mutation results in a truncated NR2E3 protein lacking 61 amino acids within the ligand-binding domain (LBD) that consists of 190 amino acids of the C-terminus end. Therefore, null function of the LBD is likely to cause ESCS in the patient. The clinical findings for this patient suggest that his left eye, with its functional L/M- and S-cones, was at an earlier stage of the syndrome than his right eye.     

Ophthalmic findings and a novel CTC1 gene mutation in coats plus syndrome: a case report

ABSTRACT

Background

Coats plus syndrome is a rare multisystem disorder, and is also a telomere-related disorder caused by CTC1 gene mutation. We reported ophthalmic findings in a Chinese child with genetically confirmed Coats plus syndrome.     

Diverse clinical phenotypes associated with a nonsense mutation in FAM161A

Purpose:

Mutations in the FAM161A gene have been reported in association with autosomal recessive retinitis pigmentosa (arRP) in several ethnic populations. This study aimed to assess the prevalence of FAM161A-related retinopathy in a British cohort and to characterise the phenotype associated with mutations in this gene.

Methods:

The FAM161A coding region and intron–exon boundaries were screened by Sanger sequencing in 120 retinitis pigmentosa (RP) patients (with likely autosomal recessive inheritance) in whom mutations in other known major RP genes have been ruled out by commercially available testing. Homozygosity mapping was performed in one consanguineous family, and high-throughput sequencing of candidate genes was performed to identify disease-associated changes. Clinical assessment of affected individuals included perimetry testing, fundus autofluorescence imaging, and optical coherence tomography.

Results:

Two patients of British origin with a homozygous mutation in FAM161A (c.1309A>T, p.Arg437*) were identified by Sanger sequencing. Homozygosity mapping and subsequent high-throughput sequencing analysis identified a further family of Pakistani origin with the same genotype. Clinical examination of affected members of these families revealed that this mutation was associated with a diverse clinical phenotype, ranging from mild disease with preservation of central acuity to severe visual impairment.

Conclusions:

Homozygosity for the c.1309A>T, p.Arg437* variant in FAM161A is a relatively common cause of arRP. The mutation occurs in diverse ethnic populations, associated with typical retinitis pigmentosa with disease onset usually in the second or third decade of life.     

A novel missense mutation in a Japanese patient with gelatinous droplike corneal dystrophy

PURPOSE: To report a novel missense mutation in TACSTD2 gene, L186P, responsible for gelatinous droplike dystrophy (GDLD). DESIGN: Case report and experimental study. METHOD: A 10-year-old Japanese boy suffering from typical GDLD was studied. A 1.1-kb DNA fragment of the TACSTD2 gene was amplified and analyzed using a molecular biological method. cDNA from the patient's cornea was also analyzed to determine which allele was expressed in the patient's corneal epithelium. RESULTS: Sequence analysis revealed that the patient is a compound heterozygote for the Q118X mutation and the L186P, the first missense mutation found in Japanese GDLD. Polymerase chain reaction-restriction fragment length polymorphism analysis from cDNA of patient's cornea revealed that the L186P missense mutation allele is expressed in the patient's corneal epithelium. CONCLUSION: We describe a novel mutation in one case of Japanese GDLD. The results confirm that the missense mutation L186P in the TACSTD2 gene is also responsible for the GDLD phenotype.     

FRMD7基因新突变位点导致先天性眼球震颤一家系的遗传学研究

目的探讨4.1埃兹蛋白－根蛋白－膜突蛋白结构域包含的7(FRMD7)基因新突变位点导致先天性眼球震颤(CN)一家系的遗传学特征。 方法2021年10月,收集于北京大学人民医院眼视光中心确诊CN家系四代19例的临床资料。采集家系中3例CN患者和9例眼正常者的外周血样本,检查受试者的最佳矫正视力(BCVA)、眼前节及眼底;评估眼球震颤的类型、头位、是否有中间带及眼位等。应用GenCap液相仪抓取目标基因技术,获取与眼部疾病相关的811个基因的外显子区域及其侧翼区域,对先证者进行高通量测序,筛选出致病基因和突变位点,并在家系中进行Sanger测序和共分离验证。使用Mutation Taster软件分析突变位点的基因突变类型;预测突变型蛋白质的三维结构和功能改变。 结果该家系的先证者(Ⅲ6)男性,11岁。此患者右眼BCVA 0.7,左眼BCVA 0.8。先证者表弟(Ⅲ9)男性,2岁,双眼视力检查配合度不佳。先证者祖父(Ⅰ1)男性,73岁。此患者右眼BCVA 0.3,左眼BCVA 0.4,双眼晶状体混浊。3患者均双眼正位,眼球震颤呈水平钟摆型,无中间带及代偿头位,眼底检查未见明显异常。此家系患者均为男性,呈现隔代遗传特征,符合X连锁隐性遗传。家系中12例受试者外周血基因检测结果显示,3例患者FRMD7基因第9外显子编码区发生半合子变异,Ⅱ6、Ⅱ8及Ⅲ8等3例眼正常女性者在该区域发生杂合变异,核苷酸变异c.822C>A,氨基酸变异p.Y274X,使终止密码子提前出现,造成蛋白质编码提前终止,大量氨基酸丢失。根据美国医学遗传学与基因组学学会遗传变异分类标准与指南,该变异被评定为疑似致病性变异。经Mutation Taster软件分析,结果显示突变性质为无义突变;突变型蛋白质三维结构和功能的预测显示该突变影响FRMD7蛋白结构的稳定性,可能使其功能受损。 结论FRMD7基因核苷酸变异c.822C>A(p.Y274X)为无义突变,属于新突变位点,此变异是该家系CN的可能致病原因,扩大了FRMD7基因突变频谱。     

Dystrophia canthorum in Waardenburg syndrome with a novel MITF mutation

AIM: To compare whether aphakic contact lenses or secondary iris-claw intraocular lenses are superior in the refractive management post-pars plana vitreolensectomy in a pedigree with a FBN1 mutation causing non-syndromic EL (NSEL) with retinal detachment (RRD). METHODS: Eight affected individuals had pars plana vitreolensectomy for bilateral EL. Twelve eyes of 6 patients had secondary iris-claw intraocular lenses inserted and 4 eyes of 2 patients were managed with contact lenses. Rhegmatogenous retinal detachment (RRD) was treated when necessary. Pre- and post-operative assessment included visual acuity, endothelial cell count and dilated fundal examination. RESULTS: Macula-on RRD was present in all individuals >18y, 64% (7/11 eyes) presenting post-vitreolensectomy with 57% having bilateral non-synchronous RRD. Surgical aphakia was managed with iris-fixated intraocular lenses (IOL group, n=6), or contact lenses (CL group, n=2). Visual acuity ≥0.3 logMAR (driving standard) was achieved in 75% of IOL group eyes and 25% of the CL group eyes. Mean loss of corneal endothelial cell count in the IOL group was 4% at 2y post-operative. CONCLUSION: In this cohort, refractive management with iris-claw IOLs provided superior outcomes to CLs and the authors recommend this as the main refractive correction in EL patients.