[Genetic and prenatal diagnosis for four families with Williams-Beuren syndrome].

Williams-Beuren syndrome is a common chromosome microdeletion syndrome. Early diagnosis and treatment are very helpful for patients and their families. This study identified the chromosome karyotype in one fetus with ultrasonography abnormalities and three children with developmental disorders from four families. This provided guidance for subsequent pregnancy and prenatal diagnosis by using routine G-banding chromosome karyotyping analysis, multiplex ligation-dependent probe amplification (MLPA) and array comparative genomic hybridization (array-CGH). In one amniotic fluid sample from a pregnant woman with fetal abnormalities on an ultrasound screen and three peripheral blood samples from three children with developmental disorders, the decreased signal of ELN gene probes at 7q11.23 and heterozygous deletions at 7q11.23 were detected by MLPA and array-CGH analysis. The laboratory genetic tests of amniotic fluid samples were normal when the mothers from the four families became pregnant again. It was concluded that MLPA and array-CGH are rapid and accurate tools for the diagnosis of Williams-Beuren syndrome and can provide more information for clinical genetic counseling.

[Analysis of copy number variations in an infant with Cri du Chat syndrome by array-based comparative genomic hybridization].

OBJECTIVE: To analyze genomic copy number variations in an infant with Cri du Chat syndrome, and to explore the underlying genetic cause. METHODS: G-banding analysis was carried out on cultured peripheral blood sample from the patient. Copy number variation analysis was performed using microarray comparative genomic hybridization, and the result was verified with fluorescence in situ hybridization. RESULTS: The infant was found to have a 46, XY, der(5) (p?) karyotype. By microarray comparative genomic hybridization, a 23.263 Mb deletion was detected in 5p14.2-p15.3 region in addition to a 14.602 Mb duplication in 12p31 region. A derivative chromosome was formed by rejoining of 12p31 region with the 5p14.2 breakpoint. The patient therefore has a karyotype of arr cgh 5p15.3p14.2 (PLEKHG4B>CDH12)× 1 pat, 12p13.33p13.1 (IQSEC3>GUC Y2C)× 3 pat. Loss of distal 5p and gain of distal 12p were verified with fluorescence in situ hybridization. CONCLUSION: The Cri du Chat syndrome manifested by the patient was caused by deletion of distal 5p from an unbalanced translocation involving chromosome 5. Microarray comparative genomic hybridization is a powerful tool for revealing genomic copy number variations for its high-resolution, high-throughput and high accuracy.

[Cytogenetic and molecular analysis of idic(Yp) in 1 infertile man and 1 prenatal fetus].

OBJECTIVE: To evaluate idic(Yp) in genetic diagnosis by examining 1 infertile man and 1 prenatal fetus using cytogenetic and molecular techniques. METHODS: Following conventional chromosome preparation, we performed G- and C-banding karyo. typing and fluorescence in situ hybridization (FISH). Then we extracted genomic DNA using standard procedures and analyzed it by array-CGH and multiplex ligation-dependent probe amplification (MLPA). RESULTS: Both cases were diagnosed as 45, X/46, X, idic (Yp11.31) mosaicism. The man showed 2 intact copies of Yp11.31-q12 (chrY:2, 710, 250-57, 428, 567, SRY, ZFY, UTY and AZF), and the prenatal fetus exhibited similar findings except a paternal deletion in the AZFc region. CONCLUSION: idic(Y) (p11.31) causes short stature and male infertility. Array-CGH and MLPA can improve the accuracy of the diagnosis of 45, X/46, X, idic (Y) mosaicism, which may contribute to the studies of the phenotype-genotype correlation and clinical genetic counseling.

[One case of 2q37 deletion syndrome: clinical and genetic diagnosis].

OBJECTIVE: 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. METHOD: 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. RESULT: 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. CONCLUSION: 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.

[Analysis of fetal chromosomal karyotype and etiology in 252 cases of early spontaneous abortion].

OBJECTIVE: To investigate the relationship between fetal chromosomal karyotype and early spontaneous abortion, and the effect of the environmental factors on spontaneous abortion. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

[A novel mutation Glu441stop (GAA to TAA) of androgen receptor gene resulting in complete androgen insensitivity syndrome].

OBJECTIVE: To identify the mutation of human androgen receptor gene (AR) in a patient with complete androgen insensitivity syndrome (CAIS). METHODS: DNA sequences of 8 exons and their exon/intron boundaries of the AR gene in the patient were amplified by PCR and directly sequenced. RESULTS: DNA sequencing revealed a nonsense mutation in exon 1, resulting in a change of codon 441 GAA (glutamic acid) to a stop codon (TAA). CONCLUSION: A novel mutation Glu441stop (GAA to TAA) of the androgen receptor gene leading to complete androgen insensitivity syndrome was identified in this study in a Chinese patient. It may help us further understanding the pathogenesis of CAIS.

[Karyotype analysis of chorionic villi from pregnant women with missed abortion using multiplex ligation-dependent probe amplification].

OBJECTIVE: To evaluate the clinical value of multiplex ligation-dependent probe amplification (MLPA) technique used in karyotype analysis of chorionic villi from missed abortion. METHODS: Feb 2008 to Oct 2008, 91 patients with missed abortion diagnosed by hormonal measurement, type B ultrasound and physical exam matched with 20 normal pregnant women undergoing artificial abortion were enrolled in this study. Chorionic villi was obtained by suction dilation and curettage in aseptic condition, then those villi was cultured and analyzed by traditional cytogenetic karyotyping method, in the mean time, the DNA extracted from villi was detected by MLPA. The results of chromosomal G-banding of chorionic villi were compared between two methods. RESULTS: The diagnostic concordance of MLPA and traditional karyotyping was observed in 92% (84/91) cases, there were 84 cases in the case group with diagnostic concordance by traditional karyotyping and MLPA except 7 cases of euploidy could not be detected by MLPA. The 84 cases included 40 normal karyotype, 29 trisomy of euchromosome, 1 double trisomy of euchromosome, 10 monosomy X, 1 monosomy X combined with trisomy of euchromosome, 2 chimaera of X chromosome, 1 structural abnormity of euchromosome. Among 7 cases with discordance diagnosis, 2 cases with trisomy and 5 cases with tetrasomy of euchromosome were identified in traditional karyotyping, however, they were all diagnosed with normal disomy by MLPA. Of 20 villi from normal pregnancy, two methods got the consistent results. CONCLUSION: The MLPA was rapid and efficacy method used for analyzing aneuploids in chorionic villi.