Clinical manifestations and genetic analysis of 4 patients with variants of FBN1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for four patients suspected for Marfan syndrome (MFS).@*METHODS@#Four male patients with suspected MFS and their family members who were treated at West China Second Hospital of Sichuan University from September 12, 2019 to March 27, 2021 were selected as the study subjects. Peripheral venous blood samples were collected from the patients and their parents or other pedigree members for the extraction of genomic DNA. Whole exome sequencing was carried out, and candidate variants were validated by Sanger sequencing. The pathogenicity of the variants was determined based on the guidelines from the American College of Medical Genetics and Genomics (ACMG).@*RESULTS@#Genetic testing revealed that all four patients have harbored variants of the FBN1 gene, including c.430_433del (p.His144fs) deletional variant in exon 5, c.493C>T (p.Arg165*) nonsense variant in exon 6, c.5304_5306del (p.Asp1768del) deletional variant in exon 44 and c.5165C>G (p.Ser1722Cys) missense variant in exon 42. According to the ACMG guidelines, the c.430_433del and c.493C>T were classified as pathogenic variants (PVS1+PM2_Supporting+PP4; PVS1+PS1+PS2+PM2_Supporting+PP4). c.5304_5306del and c.5165C>G were classified as likely pathogenic variants (PS2+PM2_Supporting+PM4+PP4; PS2_Moderate+PS1+PM1+PM2_Supporting).@*CONCLUSION@#The c.430_433del and c.5304_5306del variants of the FBN1 gene identified in this study were unreported previously. Above results have enriched the variation spectrum of the FBN1 gene and provided a basis for genetic counseling and prenatal diagnosis of patients with MFS and acromicric dysplasia.

Discussion on the status quo and solutions to the prevention and control of birth defects among primary obstetricians and gynecologists in the era of molecular genetic testing / 中华医学遗传学杂志

Birth defects are an important factor for the quality of newborn population. With the development of molecular genetic technology, an increasing number of genetic disorders leading to birth defects can now be detected. The lack of the knowledge for the basics and clinical applications of molecular genetic techniques have emerged as a shortcoming for primary care physicians who have formed the first tier prevention for birth defects. Currently, government has paid more attention to the above problems and formulated more training programs for primary obstetricians and gynecologists, e.g., "Prenatal Screening and Prenatal Diagnosis Post Training Program", "National Birth Defects Training Program", "National Primary Obstetrician Training Program". To some extent, such programs have met the urgent need for birth defect prevention in primary hospitals. But at the same time, some problems have also emerged. For instance, the knowledge for birth defects among primary obstetricians and gynecologists is poor, and there is lack of young personnel. This article has aimed to discuss the strategies to systematically improve the ability for preventing birth defects among primary care physicians by analyzing the obstacles and challenges for primary obstetricians and gynecologists in the era of molecular genetic testing.

Preparation and evaluation of quality management samples for noninvasive prenatal screening / 中华医学遗传学杂志

OBJECTIVE@#To prepare a quality control sample for non-invasive prenatal screening (NIPS) and evaluate its quality and stability.@*METHODS@#According to the biological characteristics of cell-free fetal DNA derived from the plasma of pregnant women, the simulated samples were prepared by mixing genomic DNA fragments derived from individuals with trisomy 21, trisomy 18 and trisomy 13 and background plasma. The samples were then compared with commercially made quality control products tested on various NIPS platforms and stored at -80℃, -20℃, 4℃, 24℃ and 37℃ for various periods of time.@*RESULTS@#The simulated samples have attained the expected results and could be detected on various platforms and stored at -80℃and -20℃ for at least 30 days.@*CONCLUSION@#A simulated sample was successfully prepared and possessed good stability. It can be used as the quality control sample for NIPS.

A review on the status quo and implementation methods of ethics education in standardized training for resident doctors in medical genetics department / 中华医学遗传学杂志

Clinical practice of Medical Genetics involves application of various genetic techniques for the diagnosis of genetic disorders and subsequent genetic counseling and treatment. The principles of Medical Ethics must be fully taken into account when applying genetic knowledge for medical practice. Medical Ethics education is therefore essential for the standardized training of resident doctors in medical genetics department. With a basic system of Medical Genetics Physician Training established, our hospital has made a preliminary exploration for the development of Medical Ethics teaching in resident training through various teaching practices including seminar, network teaching, case study, scene teaching and outpatient teaching, with an aim to strengthen Medical Ethnics knowledge, professionalism and communication skills, and implement Medical Ethics principles throughout clinical practice.

Improvement of algorithm based on free DNA fragment size for non-invasive prenatal test / 中华医学遗传学杂志

OBJECTIVE@#To derive more sensitive and accurate Z-scores for noninvasive prenatal testing of fetal trisomies based on a combined DNA count- and size- algorithm.@*METHODS@#One hundred eighty women at a high risk for fetal aneuploidies underwent amniocentesis. An effective cut-off value for DNA size ratio was explored. Conventional count-based Z-scores and size ratio-corrected Z scores were calculated. The reliability of each Z-score was assessed through comparison with the results of cytogenetic analysis.@*RESULTS@#With the cut-off value set as 150 bp, the ratio of small DNA is positively correlated with the proportion of fetal DNA. The sensitivity and specificity of conventional count-based Z-scores were 75.00%, and 98.86%, respectively. This rate has increased to nearly 100% with a count-based 150 bp size correction.@*CONCLUSION@#Compared with count-based methods alone, count-based Z-scores with 150 bp size correction may better predict fetal trisomies.

Prenatal diagnosis for a pregnant woman affected with Williams-Beuren syndrome / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic diagnosis for a pregnant woman and her fetus.@*METHODS@#Chromosome G-banding and microarray analysis were used to analyze the woman featuring dysmorphism and recognition defect and her fetus featuring developmental retardation.@*RESULTS@#The karyotype of the woman was normal, but chromosome microarray analysis showed that she has carried a 1423 kb deletion at 7q11.23 region. Her fetus has carried a 1530 kb deletion at the same region. Both individuals were diagnosed as Williams-Beuren syndrome.@*CONCLUSION@#Familiarity with its clinical features and proper selection of genetic testing methods are crucial for the diagnosis of Williams-Beuren syndrome.

Analysis of DYSF gene mutations in two pedigrees affected with limb-girdle muscular dystrophy type 2B / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze mutations of DYSF gene in two pedigrees affected with limb-girdle muscular dystrophy 2B (LGMD-2B).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood samples of the two probands and unaffected family members. Variant sites were screened by next-generation sequencing using gene panel as well as Sanger sequencing.</p><p><b>RESULTS</b>Four pathogenic mutations of the DYSF gene were detected, which included a de novo mutation and three mutations with uncertain significance. In pedigree 1, the proband carried compound heterozygous mutations of c.1667T to C (p.Leu556Pro) and c.5567T to A (p.Val1856Glu), which were respectively inherited from her mother and father. Proband of pedigree 2 carried compound heterozygous mutations of c.4853A to G (p.Tyr1618Cys) and c.4876G to A (p.Val1612Ile), among which c.4876G to A (p.Val1626Ile) was also found in his father and grandfather, while c.4853A to G (p.Tyr1618Cys) was detected in his mother and grandmother.</p><p><b>CONCLUSION</b>The two compound heterozygous mutations of the DYSF gene probably underlie the LGMD2B in the two pedigrees. Next generation sequencing has conferred great advantage for gene diagnosis of hereditary myopathy.</p>

Application of chromosomal microarray analysis for the diagnosis of children with intellectual disability/developmental delay and a normal karytype / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the value of chromosomal microarray analysis (CMA) for the diagnosis of children with intellectual disability/developmental delay (ID/DD) but a normal karytype.</p><p><b>METHODS</b>Peripheral blood samples from 92 ID/DD patients were analyzed with CMA using Affymetrix CytoScan 750K arrays. The results were analyzed by ChAS v3.0 software.</p><p><b>RESULTS</b>Eighteen cases (19.57%) were detected with abnormalities by CMA, among which 10 cases were diagnosed with microdeletion/microduplication syndromes. These included 2 Williams-Beuren syndromes, 2 Angelman syndromes, 2 Russell-Silver syndromes, 1 Smith-Magenis syndromes, 1 Wolf-Hirschhorn syndromes, 1 15q26 overgrowth syndrome and 1 Xq28 (MECP2) duplication syndrome. In addition, 8 cases were diagnosed with pathogenic copy number variations (pCNV).</p><p><b>CONCLUSION</b>CMA can significantly improve the diagnostic rate for patients with ID/DD, which is of great value for the treatment of such children and guidance of reproduction for their parents. Therefore, CMA should become the first-line diagnostic test for patients with ID/DD.</p>

Application of chromosomal microarray analysis in prenatal diagnosis for fetal abnormalities detected by ultrasonography / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the outcome of chromosomal microarray analysis (CMA) in prenatal diagnosis for fetal abnormalities detected by ultrasonography.</p><p><b>METHODS</b>Amniotic fluid samples from 477 pregnancies with abnormal ultrasound findings but without common aneuploidies were detected by CMA with Affymetrix CytoScan 750K arrays. The results were analyzed with ChAS v3.0 software.</p><p><b>RESULTS</b>Among the 477 samples, 24 (5.03%) were detected with pathogenic copy number variations (pCNVs) by CMA. Six (9.68%) among 62 cases with structural fetal abnormalities in multiple organ systems were detected with pCNVs, 11 (7.48%) among 147 cases with a single structural anomaly were detected with pCNVs, and 7 (2.61%) among 268 cases with a soft marker were detected with pCNVs.</p><p><b>CONCLUSION</b>CMA has offered a clear advantage over conventional karyotyping for the detection of fetal chromosomal abnormalities, and can provide an effective diagnostic tool for those with one or more structural abnormalities detected by ultrasound.</p>

Analysis of heterozygous duplication of PMP22 gene in a pedigree affected with Charcot Marie Tooth disease / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze mutation of the PMP22 gene in a pedigree affected with Charcot-Marie-Tooth disease.</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood samples of the proband and members from his family, and fetal DNA was extracted from amniotic fluid sample. Multiplex ligation-dependent probe amplification (MLPA) and array-based comparative genomic hybridization (array-CGH) analyses were carried out to determine the copy number of the PMP22 gene. Sanger sequencing was carried out to detect point mutations of the PMP22 gene.</p><p><b>RESULTS</b>A heterozygous duplication of the PMP22 gene was detected in the proband and his father, while no point mutation, insertion or deletion was found in them. No duplication or deletion of the PMP22 gene was found in other family members.</p><p><b>CONCLUSION</b>Based on clinical symptoms and genetic findings, the heterozygous duplication of the PMP22 gene is probably the cause of the disease in the proband. The fact that the father has carried the same duplication but with no detectable symptom may be due to irregular transmission pattern of the mutation. Genetic counseling for the family should therefore be with caution.</p>

Application of multiple quantitative fluorescence polymerase chain reaction approach for rapid prenatal diagnosis of common chromosome aneuploidies / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the value of multiple quantitative fluorescence polymerase chain reaction (QF-PCR) approach for rapid prenatal diagnosis of common chromosomal aneuploidies.</p><p><b>METHODS</b>A total of 4760 amniotic samples from 4649 pregnant women were analyzed with QF-PCR for 21, 18, 13, X and Y aneuploidies, and the results were compared with those of karyotype analysis.</p><p><b>RESULTS</b>The overall success rate for QF-PCR was 98.4%. All the 48 cases of 21, 18, 13, X and Y aneuploidies (including 2 case of 46, XY, rob(13:21), +21; 4 trisomy 21 in 4 twins) were detected by QF-PCR, with the overall sensibility and specificity both reaching 100%. One mosaicism of trisomy 21 and 4 mosaicisms of sex chromosome (1 misdiagnosed by karyotype analysis) were also detected by QF-PCR. Four mosaicisms of sex chromosome were verified as missed diagnosis. All the 64 cases failed by karyotype analysis were successfully analyzed by the QF-PCR approach. The total consistency rate for QF-PCR and karyotyping has reached 98.3%.</p><p><b>CONCLUSION</b>QF-PCR approach can diagnose 21, 18, 13 as well as X and Y aneuploidies within 48 hours, in addition with a portion of mosaicisms. It is an efficient and reliable method for rapid prenatal diagnosis, and therefore provide an important supplement for karyotype analysis.</p>

Altered morphology in erythrocytes of autologous blood stored at different temperatures / 中国组织工程研究

BACKGROUND:Transfusion guidelines pointed out:whole blood should be stored at (4±2)℃. The bacterial growth or loss of function should occur if the blood leaves the suitable storage conditions. Recipients wil suffer from different degrees of blood transfusion reaction or invalid infusion. OBJECTIVE:To observe morphology of erythrocytes of autologous blood stored at different temperatures using microscope. METHODS:Blood was obtained from 40 cases of acute normovolemic hemodilution and stored in ACD citrate bags. Whole blood was respectively stored at 4 ℃ and 23 ℃. Blood smear was taken respectively in the blood storage immediately, 1, 2, 3, 4, 5 and 6 hours after col ecting autologous blood. Changes in morphology of erythrocytes were observed with a microscope. Deformity rate of erythrocytes was calculated. Six blood samples were randomly selected to test pH, K+, and free hemoglobin respectively in 6-hour common temperature group and ACD banked blood within the valid period. Six blood samples were randomly selected for the bacterial culture in each group of two groups at 6 hours. RESULTS AND CONCLUSION:There were no significant differences in abnormality rates of erythrocytes between 4 ℃ and common temperature groups at each time point. The pH, K+, free hemoglobin at six hours in the common temperature group were better than those of ACD banked blood within the valid period and there was no bacterial growth in culture between the two groups. Therefore, it is feasible to transfuse autologous blood back to the patient within 6 hours of storage at room temperature.

Effect of different doses of dexmedetomidine on median effective concentration of propofol required to prevent response to Supreme laryngeal mask airway insertion in aged patients / 中华麻醉学杂志

Objective To investigate the effect of different doses of dexmedetomidine on the median effective concentration (EC50) of propofol required to prevent the response to Supreme laryngeal mask airway (LMA) insertion in aged patients.Methods ASA Ⅰ or Ⅱ patients of both sexes,aged ≥ 65 yr,with a body mass index of 20-28 kg/m2,undergoing knee operation under general anesthesia,were randomly divided into 3 groups:control group (group C),small dose dexmedetomidine group (group D1 ) and large dose dexmedetomidine group (group D2 ).Dexmedetomidine 0.4 and 0.8 μg/kg were infused intravenously over 10 min in groups D1 and D2 respectively,while group C received the equal volume of normal saline instead.Anesthesia was induced with target-controlled infusion of propofol.The initial target plasma concentration of propofol was set at 3.5,3.0 and 2.6 μg/ml in groups C,D1 and D2 respectively.Following equilibration between the plasma and effect-site concentration of propofol,LMA was inserted when BIS value was 50-60.EC50 was determined by up-and-down sequential trial.The target plasma concentration of propofol increased/decreased by 10％ in the next patient depending on whether or not the LMA insertion response occurred.Positive LMA insertion response was defined as body movement,comer of the mouth movement,biting LMA,bucking and/or wallowing during insertion.The EC50 and 95％ confidence interval (CI) of propofol required to prevent LMA insertion response were calculated with sequential method.Results EC50(95％ CI) of propofol was 3.57 μg/ml (2.91-3.87 μg/ml),3.09 μg/ml (2.66-3.53 μg/ml) and 2.62 μg/ml (2.30-3.15 μg/ml) in groups C,D1 and D2 respectively.EC50 was significantly lower in groups D1 and D2 than in group C,and in group D2 than in group D1 ( P ＜ 0.05 ).Conclusion Dexmedetomidine 0.4 and 0.8 μg/kg infused intravenously can reduce the EC50 of propofol required to prevent the response to Supreme LMA insertion in aged patients,and the effect of 0.8 μg/kg is more obvious.

The lethal activity of lymphokine activated killer cells from umbilical blood on some human cancer cells / 中国输血杂志

Objective To investigate the feasibility of lymphokine activated killer(LAK) cells induced from cord blood used as adoptive cellular immunotherapy for human cancer.Methods Mononuclear cells were separated from umbilical blood(UBMC) by Ficoll,and stimulated by IL-2.The phenotypes(CD3/ CD4/ CD8) of the mononuclear cells were assayed by Flow cytometry,and their lethal activity on K562 or SKOV6 assayed by MTT colometric.The peripheral blood mononuclear cells were used as the control.Results The in vitro anti-tumor effect of LAK from cord blood was significant.Conclusion LAK from cord blood can be a source of adoptive cellular immunotherapy in the treatment of human cancer.