Prenatal Genetic Diagnosis and Origin Analysis of Rare Complete Translocation Trisomy 18 / 中山大学学报(医学科学版)

ObjectiveTo discuss the origin of rare abnormal karyotypes of fetuses with high risk of trisomy 18 revealed by non-invasive prenatal testing （NIPT） and its impact on fertility. MethodsThe cytogenetic and molecular genetic analyses were performed on the abnormal chromosomes of a prenatally diagnosed fetus with rare complete translocation trisomy 18. Using the keywords “translocation trisomy 18” or “trisomy 18 translocation” in both Chinese and English， we searched PubMed， CNKI， SinoMed， WanFang Data， CQ VIP and the Chinese Medicine database. The relevant case series were retrieved and critically appraised. ResultsG-banded karyotype analysis showed that the maternal karyotype was 46，XX，t（9；18）（q31.2；q23） and the fetal karyotype was 47， XN， t （9； 18） （q31.2；q23）mat， +18， which was a rare complete translocation type of trisomy 18. The SNP array revealed the fetus had increased copy number of chromosome 18 and two complete chromosome 18 inherited from the mother with balanced chromosomal translocation. Literature search found two children with complete translocation trisomy 18 reported abroad. Both of them had trisomy 18 phenotype and originated from the balanced translocation between parental chromosome 18 and other chromosomes. ConclusionNIPT gives an effective advance warning of trisomy 18. SNP array not only improves the detection rate of chromosomal abnormalities， but also helps identify the origin. The karyotype is still the gold standard for prenatal diagnosis.

One case of 2q37 deletion syndrome: clinical and genetic diagnosis / 中华儿科杂志

<p><b>OBJECTIVE</b>To diagnose a new born baby with 2q37 deletion syndrome by comprehensive use of cytogenetic and molecular techniques and to investigate the phenotype characteristics and applicability of array-comparative genomic hybridization (array-CGH) and multiplex ligation-dependent probe amplification (MLPA) for detection of this syndrome.</p><p><b>METHOD</b>Following conventional chromosome preparation, G banded karyotyping was performed.Genomic DNA was extracted using standard procedures, which were then analyzed by array-CGH and MLPA.</p><p><b>RESULT</b>The patient presented with a typical face, special fist posture and congenital heart disease in 2q37 deletion syndrome. A 4.709 Mb deletion at 2q37.3 (chr2:237, 967, 852-242, 677, 269.NCBI36/hg18, including genes from COL6A3 toPDCD1) was detected by array-CGH. The results of MLPA and G banded karyotyping confirmed the existence of this deletion.</p><p><b>CONCLUSION</b>2q37.3 deletion was determined to be the cryptic cause of this case.2q37 deletion syndrome has some clinically recognizable characteristics. And array-CGH is a powerful technique for the accurate diagnosis and genotype-phenotype correlation study of this syndrome.</p>

Analysis of fetal chromosomal karyotype and etiology in 252 cases of early spontaneous abortion / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between fetal chromosomal karyotype and early spontaneous abortion, and the effect of the environmental factors on spontaneous abortion.</p><p><b>METHODS</b>Choronic villi from 252 cases of missed abortion were sampled as patient group and 50 normal pregnancies as control group. Chorionic villi were cultured and karyotype analysis was performed by G-banding. Clinical information was collected.</p><p><b>RESULTS</b>The rate of chorion chromosome abnormality in the patient group was 58.09%, significantly higher than that in the control group (4.17%) (P<0.01). Among the 140 cases of karyotype abnormalities, 81 were trisomy, 29 were monosomy X and 17 were polyploidy, accounting for 57.86%, 20.71% and 12.14% of total abnormalities, respectively. Long time and low dose radiation exposure of the pregnant female seemed to be related with spontaneous abortion(P<0.01).</p><p><b>CONCLUSION</b>Chorion chromosome abnormality is a major reason of early spontaneous abortion and karyotype analysis of chorionic villus is of clinical importance. For pregnant women, long-term exposure to computers and television seems a risk factor for missed abortion.</p>