Identification of a rare amyloid precursor protein gene mutation in a Chinese family with early-onset familial Alzheimer's disease / 中华神经科杂志

Objective To analyze the phenotype and genatics in a Chinese family with early-onset familial Alzheimer's disease(EOFAD). Methods Peripheral blood were collected in available members in the family and genomic DNA was extracted. PCR-sequencing of exon 16 and exon 17 of the amyloid precursor protein(APP) gene, presenilin 1 (PSEN1), and presenilin 2 (PSEN2) was performed. Results At age 40, two EOFAD patients (siblings) in the family developed an insidious onset of difficulties in memory. One ( Ⅱ3 in the pedigree) showed blinking. The other ( Ⅱ 5 ) showed irritability and bradykinesia.Progressive diffuse coritcal atrophy in bilateral temporal cortex was observed. Moderate diffuse cerebral dysfunction was observed in Ⅱ3 by the electroencephalogram study and neuropsychological assessments.Sequencing revealed that both patients were heterozygous for a mutation c. 2343 G ＞ A in exon 17 of APP,causing the amino acid substitution Val715Met. Four members ( Ⅱ1, Ⅱ 3, Ⅱ 5 and Ⅲ1 ) were homozygous for ApoE ε4 allele. Ⅱ9 was ε2/ε4. Conclusions This study identified a mutation, Val715Met in the APP gene in Chinese patients with EOFAD. We suggest screening for APP gene mutations in Chinese patients with EOFAD.

Cytotoxic effects of differentiated PC12 cell infected by prion protein 106-126 peptide / 中国医师杂志

Objective To investigate the cytotoxic effects of differentiated PC12 cells afterinfected by prion protein 106-126 peptide.Methods The PC12 cells were infected by prion protein 106-126peptide after differentiated by nerve growthfactor(NGF).Cell viability andthe morphological changes were observed.The energy metabolize and apoptosis was detected.Results Afterinfected by this peptide,cell viability decreasedfrom(98.1±1.9)% to (69.2±4.7)%,and apoptosis peak Was observed byflow cytometry.Aboutthe process of the cytotoxic effects,afterthe cells affected by PrP106-126,oxidative stress presented and existed continually,and then the intracellular free calcium concentrate increased from (185.74±12.93)nmol/L to (493.00±58.71)nmol/L subsequently,the activity of Ca2+ ATPase decreased from 54.92±4.05 to 34.92±4.86,the mitochondrial membrane potential decreasedto 65%,and also the energy metabolize disorder,the cells presented apoptosisinthe end.The changed Bcl-2/Bax system involvedinthe apoptosis.Conclusions Prion protein106-126 peptide caninduce apoptosisin differentiated PC12 cells and presented cellulartoxicity definitely.It might be a perfect model to study the cellular toxicity of prion protein.Continual oxidative stress could causetheintracellularfree calcium concentrate and disturb the energy metabolize,and the apoptosis might be the end-result.The oxidative stress of might play a startup and important role.

Investigation of prion protein gene in 10 sporadic Creutzfeldt-Jakob disease patients: a new novel mutation of prion protein gene / 中华神经科杂志

Objective To detect point mutations of the PRNP in 10 sporadic Creutzfeldt-Jakob disease (CJD) patients. Methods Priori protein gene open reading frame was amplified by PCR of genomic DNA extracted from peripheral blood leukocytes. Products were sequenced and digested with restriction endonuc lease Nsp I to check the phenotype at codon 129. Results Two CJD patients were confirmed at autopsy. One full sequencing of the PRNP open reading frame revealed normal, but the other revealed a single novel mutation consisting of a cytosine-to-guanine substitution at nucleotide 729, causing asparagine to replace glutamic acid at codon 211. Among 8 probable CJD patients, 2 full sequencing of the PRNP open reading frame revealed anadenine-to-guanine substitution at nucleotide 751, causing lysine to replace glutamic acid at codon 219. The patients were methionine homozygosity at codon 129. Conclusions The E211D mutation was identified in a confirmed CJD patient. The novel point mutation might be associated with familial CJD. However, E219K identified in 2 possible CJD patients was included in polymorphism of the PRNP as well as M129V. Analysis of PRNP plays an important role for diagnose of familial priori disease.

Studies on codon 129 genotype of PrP gene and phenotypic features of sporadic Creutzfeldt-Jakob disease in China / 中华神经科杂志

Objective To investigate the relationship between polymorphism at codon 129 of prion protein gene and the phenotypic features of sporadic Creutzfeldt Jakob disease(CJD)in China Methods The prion protein genotype of 14 cases with sporadic CJD were tested and clinical data were analysed Results (1) 8 cases with definite CJD and 6 cases with probable CJD were diagnosed depending on diagnostic criteria (2) Of the 8 definite CJD cases,6 were homozygous for methionine at codon 129, 2 cases were methionine/valine at codon 129,while all the probable CJD cases were methionine homozygotes (3) There were four group symptoms at onset in 12 cases with methionive homozygous at codon 129: cognitive and mental impairment as first symptom in 8 cases,ataxia in 1 case,blurred sight in 2 cases,myoclonus in 1 case;during illness there were epilepsy in 5 cases,myoclonus in 6 cases,blurred sight in 6 cases,PSD in 7 cases The longest illness duration was 20 months,and the shortest was two and a half months (4) Ataxia was the first symptoms in 2 cases with metionine/ valine at codon 129 The illness duration was 6 and 20 months,and there was no PSD (5) Spongyform degeneration in different degree and neuronal loss were seen in the 8 cases with definite CJD,synaptic deposition of abnormal PrP was shown in 5 cases Conclusions (1)Of the 14 cases with CJD, homozygosity for methionine at condon 129 of the prion protein gene was shown in 12 cases,but there was distinct phenotypic variant (2)The frequence of methionine and valine of 129 allilic distribution for sCJD was similar to that in Japan,and different from that in Western cases There was no sCJD case with valine homozygous genotype at codon 129 in our study

Familial Creutzfeldt-Jakob disease / 临床神经病学杂志

Objective To identify the clinical characteristic of familial Creutzfeldt-Jakob disease(fCJD) in one pedigree with four cases in two-generation and to investigate its pathogenetic mechanism.Methods The pedigree was investigated in the fCJD kindred,protein capture assay was used to do quantitative analysis of 14-3-3 protein in the cerebrospinal fluid.Types of PrP gene mutation were studied by polymerase chain reaction(PCR) and DNA sequence analysis.Results(1) The onset age during four cases in two-generation was lower than the sporadic CJD and it tended to go down by generations.(2) The 14-3-3 protein level in the index case's cerebrospinal fluid was 125 ng/ml,which was higher than intersection point by 13.9 times.(3) In the index case,inserting mutation in site 231 of PRNP was induced by an adenine insertion between base 788 and 789.(4) No PrP gene mutation was found in the index case's younger brother and daughter.Conclusions The fCJD is identified in the index case,which is caused by inserting mutation in the site 231 of PRNP.There is no significant difference in the clinical manifestations between fCJD and sporadic CJD.However,the onset age of fCJD is lower than the sporadic CJD and patients from the same pedigree die at familiar ages.