[Combined G-banded karyotyping and multiplex ligation-dependent probe amplification for the detection of chromosomal abnormalities in fetuses with congenital heart defects].

OBJECTIVE: To assess the value of G-banded karyotyping in combination with multiplex ligation-dependent probe amplification (MLPA) as a tool for the detection of chromosomal abnormalities in fetuses with congenital heart defects. METHODS: The combined method was used to analyze 104 fetuses with heart malformations identified by ultrasonography. Abnormal findings were confirmed with chromosomal microarray analysis (CMA). RESULTS: Nineteen (18%) fetuses were found to harbor chromosomal aberrations by G-banded karyotyping and MLPA. For 93 cases, CMA has detected abnormalities in 14 cases including 10 pathogenic copy number variations (CNVs) and 4 CNVs of uncertain significance (VOUS). MLPA was able to detect all of the pathogenic CNVs and 1 VOUS CNV. CONCLUSION: Combined use of G-banded karyotyping and MLPA is a rapid, low-cost and effective method to detect chromosomal abnormalities in fetuses with various heart malformations.

[Genetic analysis and prenatal diagnosis of two Chinese families with split hand foot malformation].

OBJECTIVE: To identify genomic aberrations underlying pathogenesis of split hand foot malformation (SHFM) in two Chinese families, and to provide genetic counseling and prenatal diagnosis for them. METHODS: Two sets of peripheral blood and amniotic fluid samples were collected from the patients. One was processed with routine culture and karyotype analysis. For another set, DNA was extracted and analyzed with array-based comparative genomic hybridization (array-CGH). RESULTS: Karyotype analysis of peripheral blood samples for both probands was normal. Karyotype analysis of the amniotic fluid from family 1 has found no abnormality. However, analysis of amniotic fluid samples from the second family showed del(7)(q21q22.1). By array-CGH analysis, both blood and amniotic fluid samples from the first family showed a 662.3 kb dup(10q24.31q24.32). Array-CGH analysis of the blood sample from the second family was normal, whilst analysis of amniotic fluid sample revealed a 19.97 Mb del(7q11.23q21.3). CONCLUSION: Array-CGH features high resolution, high accuracy and rapid diagnosis for unbalanced chromosomal aberration. The dup(10q24.31q24.32) and 19.97 Mb del(7q11.23q21.3) have been the cause of SHFM in the two families. Genetic counseling and prenatal diagnosis have been provided for both families in order to prevent this birth defect.

[Application of array-CGH and MLPA for detection of 4 cryptic unbalanced translocations].

OBJECTIVE: To use array comparative genomic hybridization (array-CGH) and multiplex ligation-dependent probe amplification (MLPA) to detect unbalanced rearrangements in 4 cases suspected to have chromosome disease but were undetected with conventional karyotype analysis, and to assess the applicability of array-CGH and MLPA for detection of unbalanced translocation. METHODS: Genomic DNA was extracted with standard procedures. All cases were analyzed by array-CGH and subtelomeric MLPA. RESULTS: All of the cases were identified to have unbalanced translocations by array-CGH analysis, among which 3 were consistent with subtelomeric MLPA analysis. For the remaining one, its chromosomal abnormality was not detected by MLPA as the imbalance has occurred outside of target regions. CONCLUSION: Both array-CGH and MLPA techniques can complement conventional karyotyping for detecting unbalanced translocations. The combination features both high resolution and efficiency for clinical use.

[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.

[Mutation analysis of the androgen receptor gene in a complete androgen insensitivity syndrome family].

OBJECTIVE: To study the mutation of the androgen receptor gene in a family with complete androgen insensitivity syndrome and to explore the pathogenicity of the mutation. METHODS: PCR and DNA sequencing were performed to study the AR gene mutation; Mbo I restriction endonuclease was used to detect existence of the mutation in normal controls; conservation of the mutation site was analyzed by comparison of the sequence of amino acid among different species. RESULTS: The DNA sequence of the three patients contained the same substitution of a single nucleotide on codon 681 GAG to GAT of exon 4, which located in the ligand binding domain of the AR receptor and led to substitution of glutamic acid to aspartic acid in the AR receptor. Their mother was heterozygote of E681D. E681D was not observed in the normal controls. The E681 site was extremely conservative in different species. CONCLUSION: The E681D mutation of the AR gene is a novel mutation of leading to complete androgen insensitivity syndrome.

[Chromosome aberration in a full-term neonate with low birth weight using microarray comparative genomic hybridization].

OBJECTIVE: To analyze the chromosome aberration in a full-term male neonate with low birth weight, and to explore the possible causes for growth retardation in intrauterine development for the neonate. METHODS: Genomic DNA was extracted from peripheral leukocytes of the neonate. Detection of genomic DNA copy number gain and loss was performed using microarray comparative genomic hybridization. Chromosome karyotype was obtained from cultured lymphocytes for the neonate and his parents in order to identify the origin of chromosome aberration. RESULTS: Gain of 10q25.2-->qter (22 Mb) was observed in the full-term neonate with low birth weight. In addition, one chromosomal region, 15q26.2-->qter (5 Mb) was lost. The karyotype of the neonate was 46, XY, -15, +der(15), t(10;15)(q25;q26)pat. CONCLUSION: The full-term neonate with low birth weight had a partial trisomy of 10q25.2-->qter with a partial monosomy of 15q26.2-->qter, both of them may contribute to the growth retardation in intrauterine development for the neonate case.

[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.