ABSTRACT
Objective Through the detections of the heterozygote frequencies tests of fetal specific genes PLAC4 and COL6A2 mRNA alleles in plasma of pregnant women, to explore its possibility of application in the noninvasive prenatal screenings of trisomy-21. Methods A toltal of 500 cases (males and females 250 cases respectively)of Han ethnic groups with Henan Provice of China who were subject to the physical checkup clinic of the Third Affiliated Hospital,Zhengzhou University from June to December, 2013 were selected as the healthy physical checkup group, and such techniques as DNA sequencing and PCR-restriction fragment length polymorphism (RFLP) were adopted to the determinations of the heterozygote frequencies of the single nucleotide polymorphism(SNP)of the PLAC4 and COL6A2 genes in the maternal peripheral blood in the healthy physical checkup group, and the differential comparisons of the determination results of the SNP heterozygote frequencies and the corresponding heterozygote frequencies in the National Center for Biotechnology Information (NCBI) database;30 cases of healthy pregnant women who spontaneously underwent pregnancy checkups at the maternity clinic were randomly selected as the healthy pregnancy group, and real-time fluorescence quantitative reverse transcription-PCR technique was adopted for determining the expression levels of PLAC4 and COL6A2 mRNA in the peripheral blood of pregnant women of 8 weeks, 10 weeks, 12 weeks, 14 weeks and 16 weeks;40 cases of the same phase were selected for acting as the specimens for the karyotype analyses of the amniotic fluid cells, among which 20 cases were trisomy-21, and the 20 cases of the negative control group, and reverse transcription-multiplex ligation dependent probe amplification (RT-MLPA) technique was adopted for screening the fetal trisomy-21. Results (1) The allele heterozygote frequencies of the SNP of the healthy physical checkup group:determinations of the genotypes and hybrid rates of the 10 SNP sites of the PLAC4 and COL6A2 genes indicated that those with higher heterozygote frequencies were respectively rs7717, rs559, rs1044598, rs59066201 and rs1042917, with population coverage of 98%. Among them, the allele hybrid rates of rs59066201 were never seen in the NCBI database;in the respective comparisons of the allele hybrid rates of rs8130833, rs9977003 and rs7844 with the hybrid rates of the NCBI database, the variations had statistical significance (P0.05);in the mutual comparisons among the expression levels of the various pregnancy weeks, the variations had statistical significance (P<0.05). The expression levels of COL6A2 mRNA in 8 weeks, 10 weeks, 12 weeks, 14 weeks and 16 weeks were respectively 8.95 ± 1.28, 11.19 ± 1.36,15.00 ± 1.58,16.87 ± 1.72 and 18.96 ± 2.79, with their expression levels rising along with the increase of the pregnancy weeks, and in the mutual comparisons between the expression levels of the various pregnancy weeks, the variations all had statistical significance (P<0.05). (3) Prenatal screenings of trisomy-21 in the validation group of the trisome:a total of 5 sites of rs7717, rs559, rs1044598, rs59066201 and rs1042917 were selected from the allele heterozygote frequencies of SNP sites were selected from the subjects of the healthy physical checkup group, and 10 cases of trisomy-21 specimens and 10 cases of negative CTR specimens were accurately determined, with the sensitivity reached 80%(17/20), and the specificity reached 90%(18/20). One case of the trisomy-21 and two negative cases were both homozygotes, and among the trisomy-21 specimens of two cases, only one SNP was a heterozygote, and it was impossible to conduct screenings on these 5 cases, with the screening accuracy reaching 100%(35/35). Conclusions Fetal specific genes PLAC4 and COL6A2 mRNA are expressed in the peripheral blood of pregnant women in different gestational age;its expression level increases with the increase of gestational age. Among them, five SNP including rs7717, rs559, rs1044598, rs59066201 and rs1042917 show highest heterogeneity rate, which is different from the corresponding heterogeneity rate in NCBI database. RT-MLPA technology is a rapid, effective, noninvasive and low cost method of prenatal screening 21 trisomy.
ABSTRACT
Objective To summarize the clinical presentations, the findings of lab tests and procedures and the genetic investigation of collagen type Ⅵ related myopathy, and to help clinicians recognize and diagnose this rare disease.Methods Seven familiar or spontaneous collagen type Ⅵ related myopathy patients diagnosed by gene detection were analyzed.We emphasized on the features of clinical manifestations, serum creatine kinase level, electromyography, lower-limb muscle MRI, muscle biopsy and correlation between genotype and pZenotype.Results Among 7 patients, 3 were caused by COL6A1 mutation, 1 was caused by COL6A2 mutation and 3 were caused by COL6A3 mutation.Two patients were familiar wZile 5 were spontaneous.HigZligZted clinical presentations were proximal weakness in lower limbs and joint contrature.Serum creatine kinase level was sligZtly elevated.ElectromyograpZy sZowed sligZt myogenic damage.Muscle MRI of tZigZ sZowed distinct pattern of muscle involvement.Muscle patZology revealed dystropZic myogenic cZanges with proliferation of connective tissue between muscle fibers.Conclusions Neurologists should recognize the features of collagen type Ⅵ related myopathy, such as progressive weakness, early-onset joint contraetures, slightly elevated serum creatine kinase and selective muscle involvement on leg MRI scan, and then perform next-generation sequencing based genetic test on suspected patients.This approach would improve the diagnostic rate of the disease.
ABSTRACT
ObjectiveTo investigate the methods and clinical significance of detecting PLAC4 and COL6A1 gene on fetal chromosome 21 from maternal peripheral blood. Methods From Oct. 2008 to Nov. 2009 30 normal pregnancies in Weifang People's Hospital were selected as pregnant group, and 9 nonpregnant women were selected as control group. Quantitative real-time PCR was used to determine transcript levels of the target genes ( PLAC4 and COL6A1 ) in blood samples. Correlation between the expression level and gestational age was analyzed. Results ( 1 ) PLAG4 mRNA was detected in peripheral blood of all pregnant women. Its maximum level was 12. 760 × 103 copies/ml, whereas the minimum was 2. 105 × 103 copies/ml, and the average value is 6. 612 × 103 copies/ml. In control group the PLAC4 mRNA could not be detected. There was statistically significant difference ( P ＜ 0. 01 ) between the two groups. ( 2 ) COL6A1 mRNA is detected in pregnant group and control group, and the concentration was 6. 847 × 103 copies/ml and 7. 322 × 103 copies/ml respectively, with no statistically significant difference ( P ＞ 0. 05 ). ( 3 ) Correlation analysis: there was no relationship between the level of PLAC4, COL6A1 mRNA and the gestational age, the correlation coefficients (r) were 0. 29 and 0. 31, and the P values were 0. 121 and 0. 168 respectively. Conclusions COL6A1 mRNA can be detected in both pregnant group and control group, so it is not specific for pregnancy. PLAC4 mRNA can be detected only in pregnant women, so it has specificity in pregnancy and can be a discriminative marker gene for prenatal dignosis of trisomy 21 fetuses.
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Objective To investigate the clinical and pathological features of Uurich congenital muscular dystrophy (UCMD). Methods The clinical aspects of 3 patients with UCMD, 2 with Duchenne muscular dystrophy (DMD) and 1 with congenital muscular dystrophy 1A (MDC1A) were analyzed. And the muscle specimens from these patients were studied using immunohistochemistry and immunofluorescence staining. Results UCMD was clinically characterized by neonatal hypotonia with proximal contracturos and distal hyperlaxity at birth or early infancy. Histochemical staining revealed muscle frber hypoplasia andinterstitium proliferation. Immunohistochemistry staining with anti-collagen Ⅵ antibody revealed complete(1/3) or partial (2/3) deficiency of collagen Ⅵ in the sarcolemma and interstitial matrix. Partial deficiency was better demonstrated by immunofluorescence staining. Conclusions The proximal contractures and distal hyperlaxity is the clinical hallmark of UCMD. Collagen Ⅵ immunolabelling can confirm the diagnosis of UCMD.