Prenatal diagnosis of a novel SOX10 mutation in a patient with syndromic hearing loss / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with syndromic hearing loss.@*METHODS@#Genomic DNA of the patient was extracted, for which 127 deafness-related genes were enriched with a chip. Following next generation sequencing, pathogenic loci in exonic regions were analyzed through comparison against the databases. Genotype of her fetus for the suspected site was determined by testing the amniotic fluid sample. qPCR method was applied to verify the deletion of a large fragment.@*RESULTS@#The proband was diagnosed with Waardenburg syndrome type 2, and had harbored a novel heterozygous deletion of the exons 3 and 4 of the SOX10 gene. Her fetus was found to carry the same deletion and presented with blue eyes and deafness after birth.@*CONCLUSION@#Waardenburg syndrome type 2 due to SOX10 gene deletion may feature autosomal dominant inheritance with incomplete penetrance. The deletion of exons 3 and 4 of the SOX10 gene probably underlies the disease in this family.

Diagnosis and reproductive guidance for a couple carrying a novel c.1893C>T mutation of the TECTA gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for an individual with postnatal deafness and provide genetic counseling for her family.@*METHODS@#Following extraction of genomic DNA from peripheral blood samples, 127 genes associated with deafness were subjected to targeted capturing and next generation sequencing. Suspected mutation was verified by Sanger sequencing.@*RESULTS@#The proband was found to carry a homozygous c.1893C>A mutation in the TECTA gene, which is located in the tectorial membrane of inner ear and may cause premature termination of translation of TECTA protein. In addition, two heterozygous mutations, c.13010C>T and c.12790G>A, were found in the USH2A gene. Whilst the former is likely to be pathogenic, the latter has unknown clinical significance. Further analysis suggested that all three mutations have derived from the parents of the proband.@*CONCLUSION@#The homozygous c.1893C>A mutation of the TECTA gene probably underlies the proband's hearing loss which conformed to an autosomal recessive inheritance.

A case of Wolf-Hirschhorn syndrome diagnosed by single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic causes for a child with multiple congenital malformations and epilepsy through analysis of copy number variations, and to correlate the genotype with the phenotype.</p><p><b>METHODS</b>G-banding karyotyping was performed on the child and her parents. Single nucleotide polymorphisms array (SNP-array) was used to map the exact chromosomal breakpoints in the proband. The result was validated with fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>G banding analysis suggested that the proband had a karyotype of 46,XX,del(4)(p15), while both of his parents had a normal karyotype. SNP-array has identified a hemizygous deletion of 13.3 Mb on chromosome 4p16.3p15.33, which has been implicated in Wolf-Hirschhorn syndrome. FISH assay has confirmed the de novo origin of the deletion, with the karyotype and clinical phenotype of both parents taken into consideration.</p><p><b>CONCLUSION</b>A case of Wolf-Hirschhorn syndrome has been diagnosed by clinical manifestation and karyotyping analysis. Compared with conventional karyotyping analysis, SNP-array has greater resolution and accuracy, and can provide useful information for genetic counseling.</p>

Prenatal diagnosis of a Pallister-Killian syndrome case through analysis of a supernumerary chromosome using single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the origin of a supernumerary small marker chromosome (sSMC) in a fetus, and to assess the feasibility of single nucleotide polymorphism array (SNP-array) for prenatal diagnosis.</p><p><b>METHODS</b>The fetal sample was subjected to karyotyping analysis. The identified sSMC was subjected to genome-wide scan using a SNP microarray chip. The results were validated with fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>The karyotype of the fetus was determined as 47,XX,+mar, which was verified by SNP microarray chip analysis as a 34.6 Mb duplication in 12p13.33p11.1. FISH analysis confirmed that the sSMC has originated from chromosome 12p.</p><p><b>CONCLUSION</b>The karyotype of the fetus was determined as 47,XX,+i(12)(p10). Tetrasomy 12p is reported to be a marker for Pallister-Killian syndrome, which may result in multi-system anomalies. SNP-array analysis can simultaneously detect microdeletions and microduplications, which may be used for prenatal diagnosis of suspected cases.</p>

Diagnosis of a case with Williams-Beuren syndrome by single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic cause for a child with mental retardation, developmental delay and multi-systemic developmental disorders by analyzing the copy number variations (CNVs) and correlating the genotype with the phenotype.</p><p><b>METHODS</b>Routine G-banding was performed to analyze the karyotype of the patient and her parents. In addition, single nucleotide polymorphisms array (SNP-array) was used to determine the CNVs, which was confirmed by fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>No karyotypic abnormality was detected upon chromosome analysis. However, SNP-array has identified a de novo hemizygous deletion of 1673 kb on chromosome region 7q11.23, which has been associated with Williams-Beuren syndrome. The microdeletion was confirmed by FISH testing.</p><p><b>CONCLUSION</b>A child with Williams-Beuren syndrome has been diagnosed by SNP-array and FISH. The de novo 7q11.23 microdeletion probably underlies the clinical manifestation of the patient. Compared with routine karyotype analysis, SNP-array is more useful for diagnosing children with multiple congenital anomalies with unclear etiology.</p>

Multiple of the median correction of Down's syndrome serum markers with pregnant body weight / 中华检验医学杂志

Objective With Pregnant women weight correction for serum marker Multiple of Median (MoM) of First trimester and second-trimester,integrated screen-ing for Down's syndrome (DS),can reduce the false positive rate.Methods The same pregnant woman were taken venous blood vessels with sterile vacuum during the first trimester (11-13 W(+ 6) d) and the second trimester (15-20 W(+ 6) d),Alpha-fetoprotein (AFP),serum free beta-human chorionic gonadotrophin (Free beta hCG) and pregnancyassociated protein-A (PAPP-A) of three kinds of serum marker screening indicators were assayed by Using Time-resolved fluoroimmunoassay (TRFIA).Screening for risk assessment software was used to calculate serum marker Multiple of Median,To assess the risks of 7 997 cases of local pregnant women DS,To construct the weight equation of local population using nonlinear weighted regression method,With maternal weight correction for serum marker Multiple of Median (MoM) of local pregnant women,Comparing the changes of screening index MoM before and after correction,chi square test to compare the detection rate and false positive rate.Results MoM values of three kinds of serum markers (al-pha-fetoprotein,free beta subunit of human chorionic gonadotropin,pregnan-cy-associated plasma protein A) decreased with the weight increasing,Screening index MoM after correction weight equation,the screening of false positives for crowd from 4.12％ down to 3.86％ (x2 =0.021,P ＞ 0.05).Setting threshold (cut-off) at 1/270,and no change detection rates were 71.4％ the local population before and after correction weight equation.Conclusion Maternal weight may affect the results of Down's syn-drome sereening.When screening proposal to set up,it is worth making weight cor-rections for serum maker multiple of median in order to get accurate risk calculation results.

First trimester combined screening for Down's Syndrome with NT, Free-βhCG and PAPP-A / 中华检验医学杂志

Objective To explore the sensitivity of using NT,combined with serum biochemical markers (Free-βhCG,PAPP-A) for Down's Syndrome screening in early stage of pregnancy.Methods Collect pregnant women aged 17-45 years old voluntary antenatal screening in our hospital from March 2009to October 2010,a total of 11882 cases.Serum Free-βhCG and PAPP-A were measured NT value was determined by ultrasound at 11-13w+64 of gestation.Calculating combined screening (NT,Free-βhCG,PAPP-A),and serum integrated screening (Free-beta hCG,PAPP-A) risk,respectively,using the risk calculation software for the same person.Results Early pregnancy screening was performed in 11 882patients,18 had a fetus with Down's syndrome,a rate of 0.15％.The detection rates of Down's syndrome in combined screening and serum integrated screening were 83.3％ and 72.2％ respectively.The specificities were 98.4％ and 97.3％ and detection efficiency were 7.18％,3.90％ respectively.Areas under the curve (AUCs) of fhst-trimester combined screening and serum integrated screening were 0.975 (95％ CI:0.943,1.007),0.901 (95％ CI:0.789,1.013) respectively.Conclusion In early stage of pregnancy,combined screening for Down's syndrome has higher sensitivity and specificity than serological screening,has higher detection rate in the same false-positive rate case,which can effectively reduce the pregnant women to receive invasive puncture.