Novel mutation in SCO2 of patients with high myopia from Enshi Tujia and Miao Autonomous Prefecture of China / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the pathogenic variants of the SCO2(OMIM 604272)gene in patients with high myopia from Enshi Tujia and Miao Autonomous Prefecture of China.METHODS: A total of 384 patients with high myopia whose spherical refractive error was ≤ -6.00 D and whose axial length was ≥26.00 mm in at least one eye were recruited. DNA was extracted by the phenol-chloroform method from 5 mL of peripheral venous blood. Sanger sequencing was performed to identify pathogenic variants in exon 2 of SCO2. The detected variants were evaluated via in silico prediction software. A total of 288 people from the same district were included as the normal control cohort.RESULTS: Seven variants were detected, namely, four synonymous variants(c.201C>T/p.=, c.576C>T/p.=, c.633A>C/p.=, c.780T>C/p.=.), two missense variants(c.187A>G/p.Ile63Val, c.59G>C/p.Arg20Pro)and one nonsense variant(c.544C>T/p.Gln182*). The two missense variants were not damaging, as predicted by PolyPhen2, SIFT and Provean. The novel nonsense variant(c.544C>T/p.Gln182*)cannot be found in the 1000 Genomes Project and was not identified in 288 normal controls. Variant Taster suggested that the nonsense variant site was conserved.CONCLUSION: The newly identified nonsense mutation may be responsible for high myopia of the patients in our cohort. SCO2 is associated with high myopia, while the incidence of SCO2 variants in high myopia in this cohort was as low as 1/384; the nonsense mutation may be a scarce variant of high myopia in the Enshi Tujia and Miao Autonomous Prefecture of China.

Mutations analysis of FRMD7 gene in idiopathic congenital nystagmus families / 中华实验眼科杂志

Objective@#To reveal the pathogenic mutations in Chinese families with idiopathic congenital nystagmus(ICN)@*Methods@#Six families with ICN were recruited from Subei People's Hospital.DNA was extracted from peripheral blood samples of all participants.All coding and exon-intronic boundary regions of the targeted gene FRMD7 were amplified with PCR and sequenced using Sanger sequencing to detect potential pathogenic mutations.This study followed the Helsinki Declaration and was approved by the Ethics Committee of Subei People's Hospital (NO.2015KY-126). All patients or their guardians signed informed consent.@*Results@#Three mutations (c.902A>G, c.1944T>A and 1945G>T) were screened in two families after co-segregation validation of intrafamilial genotype-phenotype, c.1944T>A and 1945G>T were newly detected mutations which were not detected in 100 normal controls.No significant mutations were found in the FRMD7 coding region and adjacent splicing sites in the probands of the other four families.@*Conclusions@#Two novel pathogenic mutations of FRMD7 are discovered, which expands the pathogenic mutational spectrum of FRMD7 gene causing ICN.

Analysis of HEXB gene mutations in an infant with Sandhoff disease / 中华医学遗传学杂志

Objective@#To detect potential mutations of HEXB gene in an infant with Sandhoff disease (SD).@*Methods@#Genomic DNA was extracted from peripheral blood sample of the infant. All coding exons (exons 1 to 14) and splicing sites of the HEXB gene were subjected to PCR amplification and direct sequencing.PubMed Protein BLAST system was employed to analyze cross-species conservation of the mutant amino acid. PubMed BLAST CD-search was performed to identify functional domains destroyed by thecandidate mutations. Impact of the mutations was analyzed with software including PolyPhen-2, Mutation Taster and SIFT. Whole-exome sequencing was carried out to identify additional mutations.@*Results@#The infant was found to carry compound heterozygous mutations c. 1652G>A(p.Cys551Tyr) and c. 1389C>G (p.Tyr463*) of the HEXB gene. The c. 1389C>G (p.Tyr463*) mutation may lead to destruction of two functional domains in β subunit of the Hex protein. The c. 1652G>A(p.Cys551Tyr)mutation, unreported previously, was predicted to be probably damaging by Bioinformatic analysis.@*Conclusion@#Compound heterozygous mutations c. 1652G>A(p.Cys551Tyr) and c. 1389C>G (p.Tyr463*) in the HEXB gene probably underlie the disease in this patient.

Identification and prenatal diagnosis of a novel NIPBL mutation underlying Cornelia De Lange syndrome / 中华医学遗传学杂志

Objective@#To explore the genetic basis for an infant featuring developmental delay, hand deformity and hypertonia of extremities.@*Methods@#Clinical data and peripheral blood samples of the proband and her parents were collected. Following DNA extraction, potential mutations were screened on an Ion PGM platform using a gene panel. Suspected mutation was verified by PCR and Sanger sequencing.@*Results@#A novel heterozygous nonsense mutation, c. 2521C>T(p.R841X), was identified in the NIPBL gene. The mutation may cause premature termination of translation of the adhesion protein loading factor at 841st amino acids. The same mutation was not found in her parents and 931 healthy controls, and was absent from public databases including ExAC and 1000G. Bioinformatic analysis suggested the mutation to be disease causing.@*Conclusion@#The c. 2521C>T (p.R841X) mutation of the NIPBL gene probably underlies the Cornelia De Lange syndrome in the infant. Prenatal diagnosis may be provided to this family upon their subsequent pregnancy.

Mutations analysis of FRMD7 gene in idiopathic congenital nystagmus families / 中华实验眼科杂志

Objective To reveal the pathogenic mutations in Chinese families with idiopathic congenital nystagmus(ICN) Methods Six families with ICN were recruited from Subei People's Hospital. DNA was extracted from peripheral blood samples of all participants. All coding and exon-intronic boundary regions of the targeted gene FRMD7 were amplified with PCR and sequenced using Sanger sequencing to detect potential pathogenic mutations. This study followed the Helsinki Declaration and was approved by the Ethics Committee of Subei People's Hospital (NO. 2015KY-126). All patients or their guardians signed informed consent. Results Three mutations (c. 902A>G, c. 1944T>A and 1945G>T) were screened in two families after co-segregation validation of intrafamilial genotype-phenotype,c. 1944T>A and 1945G>T were newly detected mutations which were not detected in 100 normal controls. No significant mutations were found in the FRMD7 coding region and adjacent splicing sites in the probands of the other four families. Conclusions Two novel pathogenic mutations of FRMD7 are discovered,which expands the pathogenic mutational spectrum of FRMD7 gene causing ICN.

A novel de novo mosaic mutation in PHEX in a Korean patient with hypophosphatemic rickets

X-linked hypophosphatemic rickets is caused by loss-of-function mutations in PHEX, which encodes a phosphate-regulating endopeptidase homolog. We report a 26-year-old man with X-linked hypophosphatemic rickets who showed decreased serum phosphate accompanied by bilateral genu valgum and short stature. He had received medical treatment with vitamin D (alfacalcidol) and phosphate from the age of 3 to 20 years. He underwent surgery due to valgus deformity at the age of 14 and 15. Targeted gene panel sequencing for Mendelian genes identified a nonsense mutation in PHEX (c.589C>T; p.Gln197Ter) and a mosaic pattern where only 38% of sequence reads showed the variant allele. This mutation was not found in his mother, who had a normal phenotype. This is a case of a sporadic nonsense mutation in PHEX and up to date, this is the first case of a mosaic mutation in PHEX in Korea.

Genetic analysis of a Chinese family with congenital aniridia and detection of PAX6 mutation locus / 中华实验眼科杂志

Background Congenital aniridia is a rare bilateral hereditary ophthalmopathy which impact panocular.Researches showed that congenital aniridia can be caused by different mutation locus of PAX6 genes,and the mutations are multifarious.Objective This study was to detect and anaiyze the mutations of a Chinese family with congenital aniridia by using targeted sequence capture sequencing and direct Sanger sequencing.Methods This study was approved by Ethic Committee of the First Affiliated Hospital of Zhengzhou University and followed Declaration of Helsinki.Written informed consent was obtained from subjects or their custodians before any related medical examination.A cross-sectional study was performed.A Chinese congenital aniridia family was included at the First Affiliated Hospital of Zhengzhou University in March,2016.All the family members received systemic medical examinations including nervous system and oral glucose tolerance test and then the ocular examinations were carried out.The periphery blood of 10 ml was collected from the members for genomic DNA extraction.Targeted sequence capture sequencing was performed on the DNA of proband to screen out the suspicious mutant locus.The mutation was verified by comparing the Sanger direct sequencing results from all family members.Results A total of 3 generations of 9 members were included in this congenital aniridia pedigree,and the Ⅰ 1 was dead without eye abnormality.Three patients (Ⅱ2 and her children Ⅲ1,Ⅲ2) and 5 normal family members were determined,showing an autosomal dominant inheritance pattern.No abnormal signs were found in nervous system and oral glucose tolerance test in the families.The reduce of visual acuity,ocular hypertension (21 mmHg),absence of biocular iris,opacification of corneal stroma,horizontal nystagmus,hapoplasia of fovea were found in all the sufferers.In addition,the ptosis of the left eye,congenital cataract of the right eye in Ⅱ 2 patient as well as biocular cataract and subluxation of lenses also were exhibited.The c.183C＞A mutation of the PAX6 gene was screened out to be a possible pathogenic mutation.The result of Sanger direct sequencing in the families verified a co-segregation of this mutation with mutant phenotypes.Conclusions PAX6 gene c.183C ＞A,a rare mutation in Chinese population,is a virulence mutation site in this aniridia family.

Effects of extracellular potassium on expression of HERG gene nonsense mutant L539 fs/47 / 中国病理生理杂志

AIM:To study the effects of extracellular potassium on the protein expression of wild-type HERG and its mutant L539fs/47.METHODS:Wild-type HERG (WT) or its mutant HERG-L539fs/47 (MT) were transfected into HEK293 cells for 36 h.The cells were incubated in different media containing 0.8, 4.3 or 10 mmol/L potassium.Af-ter 6 h of incubation, the protein expression of HERG was detected by flow cytometry.After 12 h of incubation, the locali-zation and quantity of the proteins were detected by laser confocal imaging and Western blot.RESULTS: Different from the retention of mutant protein in cytoplasm, wild-type HERG protein was mainly distributed in the cell membrane.The 2 proteins both increased with the changes of extracellular potassium.Flow cytometry showed that the fluorescence in the 2 groups both increased with the changes of extracellular potassium ( P<0.01 ) .The fluorescence in WT group was signifi-cantly higher than that in MT group (P<0.01).Western blot showed that mutant HERG protein included only one 60 kD band, different from the 135 kD and 155 kD bands in wild-type HERG, which were affected by the changes of extracellular potassium (P<0.05).CONCLUSION:The retention of HERG mutant L539fs/47 protein in the cytoplasm is more than wild-type HERG.Chronic high extracellular potassium keeps the stability of wild-type and mutant HERG proteins on the cell membrane.Chronic low potassium reduces the expression of HERG channel proteins in a time-dependent manner.

GLA Nonsense Mutation (c.485G>A) in a Three-Generation Family with Fabry’s Disease.

Background: GLA nonsense mutations seem to be associated with more severe clinical phenotype. Aims: Main aims were to identify the disease-causing mutation, to screen high risk family members and to predict the severity of clinical phenotype and age of onset based on genotype-phenotype analysis. Methods: Seven family members were clinically assessed and enzyme activity levels were evaluated as well. Genomic DNA was isolated from blood samples and analyzed for GLA gene mutation. Results: The proband, a 34-year-old man, was misdiagnosed for years. At 25 years of age he was diagnosed with Fabry’s disease. He had a less severe phenotype failing to express cardiac, cerebral or renal symptoms. In addition, the patient presented a ventricular septal defect as an incidental finding which has not been reported previously in Fabry’s disease. His maternal uncle had a severe classic form and, in addition, osteonecrosis of femoral head rarely reported as associated findings. All females were heterozygous; 3 of them were asymptomatic and 2 developed milder symptoms, skin and heart predominantly affected. Fabry’s disease was caused by the presence of GLA nonsense mutation c.485G>A. All close relatives of proband had one copy of the mutation. Conclusion: The family nonsense mutation c.485G>A known to predict the classic phenotype showed a wide range of clinical manifestations from severe to asymptomatic forms both in males and females supporting the intrafamilial phenotypic variability for Fabry’s disease.

A Novel MUT Gene Mutation Detected in a Female Infant with Methylmalonic Acidemia

Methylmalonic acidemia (MMA) is an autosomal recessive metabolic disease. MMA results from a deficiency of L-methylmalonyl-CoA mutase (encoded by MUT), its cofactor 5-deoxyadenosylcobalamin (MMAA, MMAB, and MMADHC), or a deficiency of methylmalonyl CoA-epimerase (MCEE). We report the case of a 5-day-old infant with MMA in which a missense and a novel nonsense mutation in MUT were present. Direct sequencing analysis of MUT revealed a heterozygous c.1106G>A (p.Arg369His) mutation in exon 6 and a heterozygous c.362_368dupAGTTCTA (p.Tyr123*) mutation in exon 2; the latter results in a premature stop codon.

Localization and identification of the mutant gene in the loop-tail mouse / 中国比较医学杂志

Objective To define the loci of the mutant gene in the loop-tail mouse.Methods To study the heredity pattern, loop-tail mice were mated with normal C57BL/6J and C3H mice.Their offsprings with loop-tail or normal phenotype were registered respectively.Microsatellite marker D1Mit113 and D1Mit149 were used to locate the mutant gene.Based on fine mapping, the candidate gene Vangl2 was found.Vangl2 gene from the loop-tail mice was amplified by PCR followed by sequencing.Incision enzyme FspBI ( BfaI ) identified the genotype of offspring from loop-tail mice intercrossing.Results Heredity test indicated that the loop-tail phenotype was controlled by a single dominant gene not with 100%penetrance but was affected by genetic background.A C-to-T transversion was at the 1345bp in Vangl2 gene of the loop-tail mice.Conclusions The C-to-T transversion introduces a pre-termination codon of amino acids and causes the phenotype of loop-tail phenotype.None homozygous mice were found in the offsprings, suggesting that the homozygous mice are lethal.