OBJECTIVE: To summarize the genetic diagnosis, low-depth copy number variation sequencing (CNV-seq) and prenatal finding in 7 fetuses with 2p16.3 deletions only involving the NRXN1 gene. METHODS: The 7 fetuses have all been found to have loss of heterozygosity at 2p16.3 by CNV-seq, which were verified by quantitative real-time PCR (qPCR). Specific regions of NRXN1 gene deletions were identified, and the CNVs were verified in their parents. Outcome of the pregnancies were followed up. RESULTS: Among 16 502 prenatal samples, 7 fetuses were found to harbor a 120 kb ~ 900 kb microdeletion in the 2p16.3 region, which yielded a prevalence of 0.424‰. The deleted region mainly involved 50 200 000-51 880 000 positions of chromosome 2 and involved only the NRXN1 gene. All of the 7 fetal CNVs were confirmed by qPCR, including 2 cases with heterozygous deletion of exons 1 to 6, 1 with heterozygous deletion of exons 1 to 19, 1 with heterozygous deletion of exons 19 to 22, and 3 with heterozygous deletion of introns 6 to 7 of the NRXN1 gene. Verification in the parents had found that one deletion was inherited from the father, 1 was from the mother, 2 cases were de novo in origin, whilst the remaining 3 had refused parental verification. After genetic counseling, one couple had elected induced abortion, 1 case has not been born yet, whilst the other 5 cases were born healthy. Follow up had identified no mental abnormalities among the children. CONCLUSION Seven fetuses with heterozygous 2p16.3 deletions only involving the NRXN1 gene were detected by CNV-seq. The specific deletion of the NRXN1 gene was verified by qPCR. Prenatal genetic counseling and fertility guidance has been provided to the particular family by combining the results of CNV testing, pedigree analysis and pregnancy outcome.
Female ; Humans ; Pregnancy ; Calcium-Binding Proteins/genetics* ; Cell Adhesion Molecules, Neuronal/genetics* ; DNA Copy Number Variations ; Nerve Tissue Proteins/genetics* ; Neural Cell Adhesion Molecules/genetics* ; Prenatal Diagnosis ; Real-Time Polymerase Chain Reaction ; Infant, Newborn

Objective To assess the clinical curative effect of accordion technique in the treatment of tibial delayed union or nonunion.Methods From February 2016 to December 2017,data of 11 patients with tibial delayed union (n=8) or non-union (n=3) who had been treated by accordion technique with an Ilizarov ring external fixator were retrospectively analyzed.10 males and 1 female were included in our study,with an average age of 41.9 years (range,21-63 years).There were 5 cases of docking site delayed union after Ilizarov transport for chronic tibial osteomyelitis.There were 3 cases of fracture site delayed union after external fixation for open tibia comminuted fracture.There were 3 cases of nonunion after tibia closed fracture,including 2 cases who had hybrid external fixation treatment,and 1 case who had conservative treatment.All the cases received accordion technique using Ilizarov ring external fixators.First,gradual compression at the fracture site was conducted until the bony contact was seen on a radiograph.After bony contact,compression was continued at a rate of 0.85 mm/d for a week,followed by distraction of 0.85 mm/d for 2-3 weeks.Afterward,a second compression was conducted using same rate and time with the distraction procedure.And there was a 7-day latent period between compression and distraction.One or two cycles of compression-distraction were needed before union was present radiographically.Results Bony union was obtained in all 11 patients after a mean time of 5.4 months (from 3 to 9 months).The mean follow-up for the 11 patients was 15.2 months (from 11 to 29 months).The mean duration of the accordion technique treatment was 50.2 d (range,35-67 d).The accordion technique was used 1 time for 8 patients,and 2 times for 3 patients.The mean duration of bone consolidation was 114.9 d (range,64-239 d).According to Paley evaluation criteria,osseous results were excellent in 8 cases,good in 3 cases,with a good to excellent rate of 100％(11/11);functional results were excellent in 7 cases,and good in 4 cases,with a good to excellent rate of 100％(11/11).Conclusion The accordion technique is a minimal invasive,safe and reliable treatment program for tibial delayed union or nonunion.