A recurrent G367R mutation in MYOC associated with juvenile open angle glaucoma in a large Chinese family.

AIM: To identify the mutations of MYOC, OPTN, CYP1B1 and WDR36 in a large Chinese family affected by juvenile open angle glaucoma (JOAG). METHODS: Of 114 members of one family were recruited in this study. Blood samples from twelve members of this pedigree were collected for further research. As a control, 100 unrelated subjects were recruited from the same hospital. The exon and flanking intron sequences of candidate genes were amplified using the polymerase chain reaction and direct DNA sequencing. RESULTS: The proband (III:10) was a seventy-three years old woman with binocular JOAG at the age of 31. A recurrent heterozygous mutation (c.1099G>A) of MYOC was identified in the three JOAG patients and another suspect. This transition was located in the first base pair of codon 367 (GGA>AGA) in exon 3 of MYOC and was predicted to be a missense substitution of glycine to arginine (p.G367R) in myocilin. Mutations in OPTN, CYP1B1 or WDR36 were not detected in this study. The G367R mutation was not present in unaffected family members or in 100 ethnically matched controls. Other variants of the coding regions of candidate genes were not detected in all participants. To date, this family was the largest to have been identified as carrying a certain MYOC mutation in China, further evidence of a founder effect for the G367R MYOC mutant was provided by our data. CONCLUSION: A MYOC c.1099G>A mutation in an autosomal dominant JOAG family is identified and the characteristic phenotypes among the patients are summarized. Genetic testing could be utilized in high-risk populations and be helpful not only for genetic counseling, but also for early diagnosis and treatment of affected patients or carriers of inherited JOAG.

The impact of antepartum interruption of intrauterine infection on the mutations of precore and core promoter regions of hepatitis B virus / 中华传染病杂志

Objective To investigate the impact of injecting hepatitis B immune globulin(HBIG)at third trimester of pregnancy on the nucleotide sequences of precore and basal core promoter(BCP)regions of hepatitis B virus(HBV)DNA.Methods One hundred and twenty pregnant women(67 in HBIG group and 53 in no-HBIG group)were enrolled in this study.Serum HBV DNA level was determined using quantitative real-time polymerase chain reaction(RT-PCR).Relevant serum markers (HBeAg,HBsAg)of HBV were detected by enzyme-linked immunosorbent assay(ELISA).Nucleotide fragments of HBV precore and BCP regions were amplified by nested PCR and then sequenced by automated DNA sequencer.Data were analyzed using t test and chi-square test.Results Sera of 33 women in HBIG group were collected before interruption with HBIG and at delivery.Precore and BCP regions of HBV DNA were amplified and sequenced successfully from double sera of 23 among 33 women. The rates of total nucleotide substitute in precore and BCP regions, that in precore region, and that in BCP region before and after interruption were 1.5% and 1.4%, 0.7% and 0.6%, 1.7% and 1.7%, respectively (Fisher's exact test, X2 =0.627, 0.689, 1.000, respectively,all P＞0.05). The rates of total mutations of hot points including 1896G→A,1899G→A,1762A→T,1764G→A before and after interruption were 27.2% and 13.0%, respectively (x2=5.717, P=0. 017). But the prevalences of these hot points mutations before and after interruption were 30.4%and 17.4%, 17.40/00 and 4.3%, 26.1% and 13.0%, 34.80/00 and 17.4%, respectively, which were all not significantly different (P＞0.05). The rates of nucleotide substitute in precore and BCP regions,that in precore region, and that in BCP region of 53 women in HBIG group and 47 women in no-HBIG group at delivery were 0.9% and 0.8%, 0.3% and 0.3%, 1.1% and 0.9%, respectively (Fisher's exact test, )x2=0.434, 0.839, 0.340, respectively, all P＞0. 05). The rates of total mutations of hot points of women in HBIG group and those in no-HBIG group at delivery were 5.7% and 10.1%,respectively, which was not significantly different (P＞0.05). These hot points mutations including 1896G→A,1899G→A,1762A→T, 1764G→A of women in HBIG group and those in no-HBIG group at delivery were 9.4% and 14.9%, 0 and 2. 1%, 7.5%0 and 10.6%, 5.7% and 12.8%, respectively,which were all not significantly different ( P＞0.05). Conclusions Antepartum interruption of HBV intrauterine infection with HBIG may not raise the nucleotide mutations in precore and BCP regions of HBV DNA. On the other hand, antepartum interruption may decrease mutations of hot points in the precore and BCP regions of HBV DNA.

Emergence of the pre C and YMDD mutations and its clinical significance during lamivudine treatment / 中华传染病杂志

Objective To explore pre C and YMDD motif mutant of hepatitis B virus during lamivudine therapy. Methods From five chronic hepatitis B patients with serum HBeAg seroconversion but HBV DNA positive by polymerase chain reaction(PCR) following lamivudine therapy, sequences of the pre C and P genes of hepatitis B virus were analyzed by direct PCR product sequencing methods. Results All the five patients were observed to have G to A variations at nucleotide 1896. However, such mutations were observed only in 2 of the 5 patients before HBeAg seroconversion emerged. Meanwhile YMDD mutations were found in all the five patients during lamivudine therapy three of which were M552I mutants, two were M552I associated with L528M. One of the five patients had no reaction to the therapy, four had HBV DNA breakthrough during therapy. Conclusions The mutants of pre C associated with YMDD mutations may arise in the patients with HBeAg seroconversion and positive HBV DNA during the treatment of lamivudine. HBV DNA should be detected in the patients with HBeAg seroconversion to exclude the pre C mutation.

Construction of serine protease gene mutant and study on pathogenicity of serine protease gene of Entero-coccus faecalis / 中华传染病杂志

Objective To construct the serine protease gene(sprE)mutant and to study the pathogenicity of sprE gene of Enterococcus faecalis.Methods Recombinant suicide vector pCQ001 of Enterococcus faecalis with pTX4577,was constructed.Then,created isogenic sprE-deficient mu- tant(*sprE)by allelic replacement was constructed.Moreover,the growth ability and the virulence of the mutant were compared with those of the wide type in vitro and in vivo respectively.A mouse peritonitis model and a rabbit endocarditis model were utilized in the study.Results The *sprE was selected by kanamycin and identified by polymerase chain reaction(PCR),pulsed field gel electropho- resis(PFGE)and Southern blot.The evidences showed that the sprE gene had a major role in helping bacteria to resist the elevated temperature and oxidative stress.The virulence of mutant decreased af- ter sprE gene was knocked out.Conclusions The *sprE of Enterococcus faecalis is constructed suc- cessfully,sprE gene is important in the pathogenesis of Enterococcus faecalis,which probably is a major virulence factor of Enterococcus faecali.