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Objective@#To explore the genetic basis for a fetus with Dandy-Walker malformation.@*Methods@#G-banding chromosomal karotyping, single nucleotide polymorphism microarray (SNP array) and fluorescence in situ hybridization (FISH) were carried out for the fetus. Chromosomal karyotyping and FISH assay were also carried out for both parents.@*Results@#SNP array has detected a 4266 kb microdeletion at 6p25.3p25.1 in the fetus, which was confirmed by FISH. FISH analysis of the parents demonstrated that the father has carried a cryptic t(6; 14)(p25.1; p13) translocation, while the fetus has a der(6)t(6; 14)(p25.1; p13) derived the paternal translocation.@*Conclusion@#The der(6)t(6; 14)(p25.1; p13) probably underlies the Dandy-Walker malformation in the fetus. The 6p25.3p25.1 microdeletion is due to unbalanced gametes produced by the father’s cryptic balanced translocation.
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Objective@#To explore the influence of uniparental disomy (UPD) on bipartite and tripartite paternity testing.@*Methods@#Two cases of paternity testing were analyzed by multiplex amplification and capillary electrophoresis typing. Suspected UPD was verified by using single nucleotide polymorphism array (SNP array). Parental power index was calculated by using a bipartite or tripartite model.@*Results@#The two cases were found to harbor respectively three short tandem repeats on chromosome 2 and two short tandem repeats on chromosome 15. SNP array verified that both cases were of UPD. Case 1 had a parental power index of 122274987565.23 by a tripartite model, while case 2 had a parental power index of 13500.8463 by a bipartite model. Based on the technical specification, the conclusions supported a biological parent-child relationship in both cases.@*Conclusion@#UPD may lead to misjudgment of paternity testing. The possibility of UPD should be considered when certain loci which do not conform to Mendelian inheritance have aggregated to one chromosome.
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Objective@#To explore the genetic basis for a fetus featuring increased nuchal thickness.@*Methods@#Routine G-banding karyotyping and single nucleotide polymrophism array were carried out to detect genomic copy number variations (CNVs) in the fetus.@*Results@#The fetus was found to harbor a heterozygous 3.8 Mb deletion in the 2q22.2-q22.3 region encompassing the ZEB2 gene, which is closely associated with Mowat-Wilson syndrome (MWS).@*Conclusion@#Haploinsufficiency of the ZEB2 gene may predispose to MWS. Lack of knowledge regarding to the ultrasonographic features of MWS may lead to misdiagnosis of the syndrome.
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Objective@#To analyze the clinical phenotype and genomic abnormality of an adult featuring congenital heart defect and multiple developmental disorders.@*Methods@#The patient was subjected to conventional G-banding chromosomal karyotyping and single nucleotide polymorphism microarray (SNP-array) analysis.@*Results@#The patient showed a normal karyotype, while SNP-array revealed a 42.7 Mb mosaic uniparental disomy (UPD) in the 11p15.5p12 region ([hg19] chr11: 491 333 - 43 189 376).@*Conclusion@#The mosaicism of UPD of 11p15.5p12 region probably underlies the congenital heart defect and developmental disorders in the patient.
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Objective@#To analyze a family with recurrent fetal copy number variations (microdeletion and microduplication, respectively) of 1p31.1 using single nucleotide polymorphism-based array (SNP-array) and G banding chromosomal karyotyping.@*Methods@#Amniocentesis and chorionic villus sampling were performed for a woman during the two pregnancies. Whole genome SNP-array was used to detect genomic imbalance of the fetus. The couple was also subjected to G-banding chromosomal analysis and SNP-array analysis.@*Results@#SNP-array showed a 1p31.1 (70 164 686-83 474 843)×1 and a 1p31.1 (70 164 686-83 479 747) × 3 in the fetuses during the two pregnancies, respectively. SNP array results of the couple appeared to be normal. The mother of the fetuses had a 46, XX, inv(1)(p31.1p32.1) karyotype.@*Conclusion@#The paracentric inversion in chromosome 1 in the gravida probably underlies the recurrent 1p31.1 copy number variations in the fetuses. SNP-array combined with G banding chromosomal analysis are suitable for prenatal diagnosis for recurrent microdeletion and microduplication in the same chromosomal region, and can provide detailed information for genetic counseling.
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Objective To explore the diagnosis strategy of Rubinstein-Taybi syndrome. Methods SNP-array technology was used to analyze the variation of whole genome copy number in one patient whose clinical features were in accord with the diagnosis of Rubinstein-Taybi syndrome. Results Two-months-old male patient had been detected to have 1 . 8 Mb deletion mutation in 16 p 13 . 3 region (chr 16:2903942-4748851 ), in which the pathogenic CREBBP gene was located. Conclusions Chromosomal microarray analysis (CMA) technology, such as SNP-array, can be used to make a molecular diagnosis of Rubinstein-Taybi syndrome.
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[ ABSTRACT] AIM:To evaluate the clinical application of single nucleotide polymorphism array ( SNP array) in prenatal diagnosis for screening the abnormality of women with Down’ s syndrome ( DS) .METHODS:The amniotic fluid samples ( n=312) collected by amniocentesis for the DS screening abnormality women were tested by karyotyping and SNP array analysis, respectively.The findings of karyotyping and SNP array analysis were compared.RESULTS:Two cases of trisomy 21 were identified by karyotyping and SNP array analysis, but SNP array analysis failed to identify 6 cases of chro-mosome balanced structural rearrangement.SNP detected 176 cases copy number variants ( CNVs) in 303 cases normal karyotype were detected by SNP, including 106 benign CNVs, 61 variants of unknown significance (VOUS), 9 de novo CNVs, and none of them was pathogenic.The distribution difference of CNVs in DS screening positive group and DS screening positive plus advanced maternal age group was not statistically significant ( P>0.05) .Furthermore, we reported 14 kinds of CNVs for the first time in population.CONCLUSION:SNP array can further assure chromosome microdupli-cation/microdeletion.In normal karyotype fetus of prenatal diagnosis, SNP can detect some clinical significant CNVs.