RDH12-associated retinal degeneration caused by a homozygous pathogenic variant of 146C>T and literature review

AIM:To describe the clinical,electrophysiological,and genetic features of an unusual case with an RDH12 homozygous pathogenic variant and reviewed the characteristics of the patients reported with the same variant.METHODS:The patient underwent a complete ophthalmologic examination including best-corrected visual acuity,anterior segment and dilated fundus,visual field,spectral-domain optical coherence tomography(OCT)and electroretinogram(ERG).The retinal disease panel genes were sequenced through chip capture high-throughput sequencing and Sanger sequencing was used to confirm the result.Then we reviewed the characteristics of the patients reported with the same variant.RESULTS:A 30-year male presented with severe early retinal degeneration who complained night blindness,decreased visual acuity,vitreous floaters and amaurosis fugax.The best corrected vision was 0.04 OD and 0.12 OS,respectively.The fundus photo and OCT showed bilateral macular atrophy but larger areas of macular atrophy in the left eye.Autofluorescence shows bilateral symmetrical hypo-autofluorescence.ERG revealed that the amplitudes of a-and b-wave were severely decreased.Multifocal ERG showed decreased amplitudes in the local macular area.A homozygous missense variant c.146C>T(chr14:68191267)was found.The clinical characteristics of a total of 13 patients reported with the same pathologic variant varied.CONCLUSION:An unusual patient with a homozygous pathogenic variant in the c.146C>T of RDH12 which causes late-onset and asymmetric retinal degeneration are reported.The clinical manifestations of the patient with multimodal retinal imaging and functional examinations have enriched our understanding of this disease.

Identification and functional analyses of a novel FOXL2 pathogenic variant causing blepharophimosis, ptosis, and epicanthus inversus syndrome

AIM: To discover the molecular pathogenic basis of the blepharophimosis, ptosis, and epicanthus inversus syndrome(BPES), and to predict the clinical subtype according to in vitro experiments, which is significant to the prognosis.METHODS: A 3-year-old sporadic female patient with typical clinical manifestations of BPES was enrolled. The coding region of forkhead box L2(FOXL2) gene was sequenced, and the functional assays were performed in vitro by Western blotting, subcellular localization experiment, luciferase reporter assay, and quantitative realtime polymerase chain reaction.RESULTS: A novel FOXL2 point pathogenic variant(c.274G>T) was detected, resulting in a truncated protein(p.E92*). Functional studies demonstrated that the FOXL2 pathogenic variant induced the subcellular mislocalization and the abnormal transcriptional activity on promoters of the steroidogenic acute regulatory protein(StAR or STARD1) gene and the odd-skipped related 2 transcription factor(OSR2) gene.CONCLUSION: A novel pathogenic variant is identified to expand the spectrum of the known FOXL2 mutations. The in vitro experiments provide reference data and more insights to the molecular pathogenesis of BPES. The predicted high risk of ovarian insufficiency makes it significant for the patient enrolled to have further follow-up and therapy concerning female endocrinology.

Identifying a novel frameshift pathogenic variant in a Chinese family with neurofibromatosis type 1 and review of literature

AIM:To detect the pathogenic gene variant in a family with neurofibromatosis type 1(NF1).METHODS:This patient with NF1 was sequenced using target sequence capture and high-throughput sequencing technology.After detecting the suspicious pathogenic variant type,the pathogenic variant sites of the patient and the patient’s family members were verified by multiple ligation dependent probe amplification and Sanger sequencing.Sift,polyphen-2,Mutation Taster and GERP++software were used to predict the pathogenicity of the unknown loci.The clinical data,diagnosis and treatment process of the patients were reviewed.Using the keyword“NF1;frameshift pathogenic variant”,relevant literature was gathered for analysis from Chinese and international databases,with articles dating from the establishment of each database to April 2022.RESULTS:A heterozygous frameshift pathogenic variant of NF1 in exon 33 was detected in the patient.The insertion of adenine in coding region 4486 resulted in the replacement of isoleucine with asparagine in protein 1497.Sanger sequencing validation and segregation analysis were performed,which demonstrated that the NF1 gene was cosegregated with the disease phenotype in this family.This study identified a novel NF1 heterozygous frameshift mutation c.4486dupA(p.I1497Nfs*12).Relevant literature retrieval found 7 Chinese articles and 12 foreign articles.With NF1 gene mutation,mutation types are diverse,including point mutation,frameshift mutation,splice site mutation,exon mutation,chimeric mutation and de novo mutation.Foreign reports are based on autosomal dominant inheritance.CONCLUSION:This study’s results demonstrate that a novel deletion in exon 33 caused NF1 in this Chinese family,expanding the mutational spectrum of the NF1 gene.

Hereditary cancer syndromes

Hereditary cancer syndromes(HCSs)are arguably the most frequent category of Mendelian genetic diseases,as at least 2%of presumably healthy subjects carry highly-penetrant tumor-predisposing pathogenic variants(PVs).Hereditary breast-ovarian cancer and Lynch syndrome make the highest contribution to cancer morbidity;in addition,there are several dozen less frequent types of familial tumors.The development of the majority albeit not all hereditary malignancies involves two-hit mechanism,i.e.the somatic inactivation of the remaining copy of the affected gene.Earlier studies on cancer families suggested nearly fatal penetrance for the majority of HCS genes;however,population-based investigations and especially large-scale next-generation sequencing data sets demonstrate that the presence of some highly-penetrant PVs is often compatible with healthy status.Hereditary cancer research initially focused mainly on cancer detection and prevention.Recent studies identified multiple HCS-specific drug vulnerabilities,which translated into the development of highly efficient therapeutic options.

Cerebrotendinous xanthomatosis presenting with schizophrenia-like disorder:A case report

BACKGROUND Cerebrotendinous xanthomatosis(CTX)is a rare autosomal recessive lipid-storage disorder caused by mutations in CYP27A1.Psychiatric manifestations in CTX are rare and nonspecific,and they often lead to considerable diagnostic and treatment delay.CASE SUMMARY A 33-year-old female patient admitted to the psychiatric ward for presentation of delusions,hallucinations,and behavioral disturbance is reported.The patient presented with cholestasis,cataract,Achilles tendon xanthoma,and cerebellar signs in adulthood and with intellectual disability and learning difficulties in childhood.After the characteristic CTX findings on imaging were obtained,a pathological examination of the Achilles tendon xanthoma was refined.Replacement therapy was then initiated after the diagnosis was clarified by genetic analysis.During hospitalization in the psychiatric ward,the nonspecific psychiatric manifestations of the patient posed difficulty in diagnosis.After the patient’s history of CTX was identified,the patient was diagnosed with organic schizophrenia-like disorder,and psychotic symptoms were controlled by replacement therapy combined with antipsychotic medication.CONCLUSION Psychiatrists should be aware of CTX,its psychiatric manifestations,and clinical features and avoid misdiagnosis of CTX for timely intervention.

Treatment of pediatric intracranial dissecting aneurysm with clipping and angioplasty,and next-generation sequencing analysis:A case report and literature review

BACKGROUND Large intracranial dissecting aneurysm(IDA)in the anterior cerebral circulation is rare in children.There has been no consensus on the diagnosis and treatment for IDA in children.CASE SUMMARY We report a 3-year-old boy with a large ruptured IDA in the right middle cerebral artery(16 mm×14 mm).The IDA was successfully managed with clipping and angioplasty.Next-generation sequencing of the blood sample followed by bioinformatics analysis suggested that the rs78977446 variant of the ADAMTS13 gene is a risk for pediatric IDA.Three years after surgery,the boy was developmentally normal.CONCLUSION Clipping and angioplasty are effective treatments for ruptured IDA in the anterior cerebral circulation.ADAMTS13 rs78977446 is a risk factor for pediatric IDA.