Objective To analyse MMACHC mutations for 45 pedigrees with combined methylmalonic aciduria and homocyctinuria by Sanger sequencing, and to discuss the utility of prenatal genetic diagnosis for these pedigrees.Method Peripheral blood was collected from 45 probands and their parents from 2012-2015 in Genetic Counselling Clinic of the First Affiliated Hospital of Zhengzhou University, and the DNA were extracted from the blood.Then the coding sequence of MMACHC gene was amplified by PCR, and the PCR products were further sequenced to detect mutations for each pedigree.For 12 families, chorionic villus sampling was performed on the pregnant women to make prenatal genetic diagnosis.Result There were 14 distinct mutations detected in the 45 pedigrees, and the most frequent mutations are c.609G>A(W203X),c.658-660delAAG(K220del)and c.80A>G (Q27A).Two of those mutations have not been reported before:one is a splicing site mutation c.81+1G>A;while the other is a missense mutation c.665A>G,p.Y222C.Most mutations were found in exon 4.Among the 12 pedigrees who received prenatal diagnosis, 2 fetuses were normal, 7 fetuses were carriers of heterozygous mutation, and the other 3 fetuses were patients with compound heterozygous mutation or homozygous mutation.The couples whose fetuses were normal or carriers continued the gestation, while the couples whose fetuses were patients decided to terminate the pregnancy.After delivery, the outcome of the fetuses was the same as the prenatal diagnose results.Conclusion Two novel mutations of MMACHC were identified and prenatal genetic diagnosis helps to avoid the delivery of combined methylmalonic aciduria and homocyctinuria patients.

Objective To analyze the mutation of MUT with Sanger sequencing technology to explore the feasibility of its application in prenatal diagnosis.Methods MUT sequencing was performed in 24 pedigrees who had history of isolated methylmalonic acidemia (MMA) babies and came to the First Affiliated Hospital of Zhengzhou University and Newborn Screening Center of Maternal and Child Health Hospital of He'nan Province between October 2012 and June 2015 for genetic counseling.Meanwhile,another 100 cases of normal controls also had their MUT gene sequence analyzed.After confirming the genotype of each pedigree,we collected the villi of nine high-risk fetuses in nine pedigrees whose parents were prepared for prenatal diagnosis.Results Totally,25 kinds of MUT gene mutations were identified among the 24 isolated MMA pedigrees,in which 11 were novel mutations including one nonsense mutation [c.616C＞T(p.Q206X)],six missense mutations [c.613G＞A(p.E205K),c.894T＞G(p.1298N),c.1009T＞C(p.F337L),c.1154G＞T(p.L385W),c.1663G＞A(p.A555T) and c.1675G＞A(p.R559G) and four frame shift mutations [c.626-627insC(p.P209Pfs*2),c.755-756insA(p.H252Qfs*6),c.756-757insA(p.M253Nfs*5) and c.1581-1582insA(p.A528Ifs*4)].None of the above mutations was detected in the controls.Finally,among the nine pedigrees for prenatal diagnosis,two were determined to have normal MUT gene,four were found to be heterozygous mutation carriers of MUT gene and three were confirmed as complex heterozygous or homozygous mutation carriers.Families of fetus who had normal MUT gene or fetuses who were carriers chose to continue the pregnancy,while those who had heterozygous mutation of MUT gene chose termination.The results of follow-up of newborns were consistent with that of prenatal diagnosis.Conclusions We found two novel mutations in MUT gene that might lead to isolated MMA.And Sanger sequencing technology for MUT gene sequencing analysis might effectively avoid the birth of isolated MMA children.

Objective To explore the clinical and genetic features of Rubinstein-Taybi syndrome (RSTS). Methods The clinical data of 2 children with RSTS were reviewed and analyzed. Results Two male children (3 years old and 4 months old) were admitted to hospital because of growth retardation. Both of them were characterized by short stature, language and motor retardation, excessive hairiness and cryptorchidism. Case 1 had slightly broad thumbs and toes, and case 2 had distinctive facial features of high arched palate, broad nasal bridge, ptosis, and obviously broad thumbs and toes. Cardiac dysplasia was found in both of them by echocardiography. The c.152T>G (L51X) heterozygous mutation was found in case 1 by high throughput sequencing and genomic chip technology, and this mutation has not been reported. Deletion of 2.5 Mb in chromosome 16p13.3 region was found in case 2. Conclusions The main clinical manifestations of RSTS are excess hair, deformity of thumbs and toes, deformity of the heart development, and growth retardation. Molecular detection can help the clinical diagnosis.

Objective To evaluate the efficacy of non-invasive prenatal screening (NIPS) in the detection of fetal aneuploidies.Methods Cell free DNA was sequenced in 5 566 pregnant women to identify the fetal aneuploidies in the First Affiliated Hospital of Zhengzhou University from January 1st,2015 to March 15th,2016.Among them,5 230 (93.96％,5 230/5 566) were singleton pregnancies and 336 (6.04％,336/5 566) were twin pregnancies.In singleton pregnancies,1 809 (34.59％,1 809/5 230) were women with advanced maternal age,and 3 421 (65.41％,3 421/5 230) were young women.The positive results of NIPS were validated by karyotyping through invasive procedures and neonatal outcomes were followed up by telephone.Results Among the 5 566 women,69 (1.24％,69/5 566) got positive NIPS results,with 66 in singleton pregnancies and 3 in twin pregnancies.Two were monochorionic diamniotic twins and 1 was dichorionic twin pregnancy.The positive predictive value of NIPS for trisomy 21,18 and 13 were 100.0％,90.9％ and 100.0％,and was 55.6％ for sex chromosome aneuploidies.There was no false negative case found during the follow-up.In the advanced maternal age group and young women group,the prevalence rates of fetal chromosomal aneuploidies were 1.11％ (20/1 809) and 0.94％ (32/3 421),respectively.In the young women with soft markers in fetal ultrasound,the prevalence of fetal chromosomal aneuploidies was 1.44％ (7/487),and in serum high risk women,it was 0.94％ (7/747).In women with the serum screening risk with cut-off value,0.89％(9/1 016) had fetal aneuploidies,and the prevalence was 0.77％(9/1 171) in volunteers.There was no statistically significant difference among these groups (P=0.636).Conclusions There is no difference in the detection rate of fetal aneuploidies between high-risk women in serum screening and volunteers in NIPS.NIPS is more suitable as a first line screening test for women without fetal ultrasound abnormalities.It should be used carefully when there is ultrasound abnormalities.