AB0108 USING RNA SEQUENCING TO IDENTIFY GENE EXPRESSION SIGNATURES ASSOCIATED WITH RESPONSE TO ABATACEPT IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a common chronic autoimmune disease. Abatacept (CTLA4-immunoglobulin) is one of the biological disease-modifying antirheumatic drug (bDMARD) for RA patients with indequate response to methotrexate. Recently, Yokoyama-Kokuryo et al. compared gene expression levels between abatacept responders and non-responders in RA patients using a microarray and found that type I IFN score and expression levels of nine genes may be used as a biomarker to predict response to abatacept. However, little study used RNA sequencing (RNA-seq) to identify whole blood gene expression signatures to predict therapeutic response to abatacept.

Objectives:

The aim of this study is to identify gene expression signatures to predict therapeutic responses to abatacept in RA patients using RNA-seq.

Methods:

This study is a single-center, prospective study. We used a PAX gene Blood RNA kit to collect whole blood at baseline and 4 weeks after abatacept treatment from RA patients. We also measured DAS28, physician global assessment, HAQ, ESR, CRP at baseline and 12 week to calculate EULAR response at 12 week. Patients with good EULAR response were defined as responders and those with moderate or no EULAR response were defined as non-responders.

Results:

We finally conducted RNA-seq for whole blood from 7 RA patients initiating abatacept therapy. Of the 7 RA patients, one was non-responder and 6 were responders. We first use DESeq2 to analyze the differentially expressed genes of non-responder and responder before taking the drug. We used hierarchical clustering and PCA to evaluate the overall similarity of the samples, and group the patient data, and find that the nonresponder can be distinguished from responders. Subsequently, we analyzed the differentially expressed genes of the two groups of non-responder and responder patients before taking the drug. Before treatment, we found that 72 genes had a higher expression in the non-responder, and 23 genes had a higher expression level in responders. Figure 1 showed the top 20 DEG Heatmap between the non-responder and responders.

Using these two sets of genes for GO analysis, we found that most of the pathways in the non-responder are related to immune response and cytokine production, and most of the pathways in the responders are related to antigen processing and MHC class II.

Figure 1.

Top 20 DEG Heatmap between non-responder and responders

Conclusion:

The study showed that most of the pathways in RA patients with no EULAR response to abatacept are related to immune response and cytokine production; while most of the pathways in RA patients with moderate/good response to abatacept are related to antigen processing and MHC class II.

References:

[1]Yokoyama-Kokuyo W, Yamazaki H, Takeuchi T, et al. Identification of molecules associated with response to abatacept in patients with rheumatoid arthritis. Arthritis Research & Therapy. 2020;22:46.

Disclosure of Interests:

Hsin-Hua Chen Grant/research support from: This is an investigator-sponsored trial with Bristol-Myers Squibb who provides funding support., Wen-Cheng Chao: None declared, Jing-Rong Wang: None declared, Tai-Ming Ko: None declared

Glucose-6-phosphatase gene mutations in Taiwan Chinese patients with glycogen storage disease type Ia

Glycogen storage disease type Ia (GSD Ia) is caused by a deficiency of glucose-6-phosphatase (G6Pase) activity. Eighteen GSD Ia families were studied for G6Pase gene mutations. Thirty-two mutations were found in 36 GSD Ia chromosomes: 16 were 727 G-->T (44.44%); 13 were R83H (327 G-->T; 36.11%); 1 was 341delG; 1 was 933insAA; and 1 was 793 G-->T. The 727 G-->T and R83H mutations together accounted for 80.56% (29/36) of the GSD Ia chromosomes. These two mutations were easily examined by polymerase chain reaction-based methods, and the prenatal diagnosis of a non-affected fetus was successfully made. The 727 G-->T mutation is the predominant mutation in Japanese GSD Ia patients, but is rarely seen in Western counties. The 727 G-->T mutation is also the most prevalent mutation in Taiwan Chinese, although the incidence is not as high as in Japan.

Molecular genetic study of Pompe disease in Chinese patients in Taiwan

Pompe disease is caused by mutations in the acid alpha-glucosidase (GAA) gene. Multiple kinds of mutations in the GAA gene have been reported worldwide. In order to elucidate the molecular basis of the disease in Taiwanese patients of Chinese origin, we have recruited 11 unrelated families who had at least one member with Pompe disease for study. We used 16 pairs of oligonucleotide primers to amplify all the coding regions from exon 2 to 20 in the family members. The coding regions were sequenced on both the sense and antisense strands. We identified 7 different mutations in 17 alleles but failed to identify the defects in the other 5 alleles. The most common defect was D645E (Asp645Glu), accounting for 36% (8/22 alleles) of mutations, followed by G615R (Gly615Arg) (3 alleles); 1411del4 (Glu471-shift) (2 alleles); and one allele each of R600H (Arg600His); deltaN675 (deltaAsn675); 2380delC (Arg794-shift) and 2815delGT (Val939-shift). The molecular defects of Pompe disease are highly heterogeneous in Chinese. Characterization of the molecular defects of the disease is useful for a genotype-phenotype correlation and for genetic counseling and prenatal diagnosis.

Prenatal diagnosis of Apert syndrome with widely separated cranial sutures

A 35-year-old Taiwanese woman visited us for prenatal evaluation in the 20th week of pregnancy. Both clinical observation of the mother and analysis of maternal DNA indicated a diagnosis of Apert syndrome. Sonographic examination of the fetus demonstrated findings that were consistent with this diagnosis; however, no prematurely fused cranial sutures were observed. The pregnancy was terminated after genetic counselling and fetal DNA analysis showed the same mutation as found in the mother. Autopsy of the abortus revealed the same findings as were detected by sonography; however, all cranial sutures were widely separated. These findings indicate that, in Apert syndrome, craniosynostosis and syndactyly may develop asynchronously up to 20 weeks of pregnancy.

Prevalence study and molecular characterization of alpha-thalassemia in Filipinos

In order to determine the prevalence and molecular basis of alpha-thalassemia (thal) among Filipinos, a total of 2954 Filipinos in Taiwan were enrolled in this study. A complete blood count was done for every subject. Those with microcytosis (MCV less than 82.5 fl) were studied with hemoglobin (Hb) high-performance liquid chromatography to determine the levels of Hb A2 and Hb F, and with an enzyme immunoassay to determine plasma ferritin levels. Those who had microcytosis and normal or low levels of Hb A2 and Hb F were further studied with molecular methods for alpha-globin gene mutations. We used Southern blot hybridization and/or the polymerase chain reaction to detect Southeast Asian deletion, Filipino deletion, rightward and leftward single alpha-globin gene deletions, and Hb Constant Spring and Hb Quong Sze. Specific amplification and direct DNA sequencing of the alpha2- and alpha1-globin genes were carried out in apparent alpha-thal carriers without any of the above-mentioned mutations. Our results showed that in Filipinos the prevalence of alpha-thal 1 was 5% (147 carriers) and that of alpha-thal 2 was 1.7% (49 carriers); two had Hb H disease. Among the alpha-thal 1 carriers, 89 had the Southeast Asian deletion and 58 had the Filipino deletion. Among the alpha-thal 2 carriers, 48 had a rightward deletion and one had a leftward deletion. None had Hb Constant Spring or Hb Quong Sze. Specific amplification and DNA sequencing in five apparent alpha-thal carriers did not reveal mutations in the 2-kb region spanning the alpha2- and alpha1-globin genes. The molecular defects of alpha-thal in Filipinos were different from those in the neighboring ethnic groups. Elucidation of the alpha-thal mutations in Filipinos is useful in the genetic counseling and prenatal diagnosis of this common disease.

Transmission of de novo mutations of the deleted in azoospermia genes from a severely oligozoospermic male to a son via intracytoplasmic sperm injection

OBJECTIVE

To investigate the transmission of microdeletions in the deleted in azoospermia (DAZ) genes to a male offspring via intracytoplasmic sperm injection (ICSI).

DESIGN

Case report.

SETTING

Reproductive unit of a university teaching hospital.

PATIENT(S)

A 29-year-old, severely oligozoospermic male with microdeletions of the DAZ genes in Yq interval 6 and his son, who was conceived via ICSI.

INTERVENTION(S)

DNA screening for the microdeletions in Yq interval 6 with 24 sequence tagged sites with the use of polymerase chain reaction amplification for the patient, the patient's father, and the patient's son. Paternity identification was performed using nine hypervariable short tandem repeats.

MAIN OUTCOME MEASURE(S)

Deletion mapping of Yq interval 6 from sequence tagged sites and electropherogram of short tandem repeats for DNA fingerprinting.

RESULT(S)

The son had the same microdeletions of the DAZ genes as the patient, and the patient's father had normal DAZ genes. The paternity of the patient, the patient's father, and the patient's son was verified.

CONCLUSION(S)

De novo DAZ microdeletions in an infertile male can be transmitted to a male offspring via ICSI. DNA screening tests for DAZ genes before ICSI may help in the genetic counseling of patients with idiopathic azoospermia or severe oligozoospermia.

Laminaria and sulprostone in second trimester pregnancy termination for fetal abnormalities

The efficacy and safety of intracervical placement of laminaria and intravenous prostaglandin E2 (sulprostone) infusion for termination of second-trimester pregnancies with abnormal fetuses was investigated. One hundred and six pregnant women at 13-29 weeks' gestation with fetal anomalies underwent laminaria tent insertion into the cervical canal on admission. The next morning, Sulprostone infusion was started at a rate of 16 microg/h and increased by 16 microg/h every 30 min to induce uterine contractions. Induction-to-abortion time (IAT), success and complete abortion rates, and sulprostone-related side effects were registered. The overall success and complete abortion rates within 24 h were 91.5 and 80.2%, respectively. The mean IAT was 12.1+/-7.6 h. The incidence of nausea and/or vomiting was 17.9%, with 1.7 episodes per case. Diarrhea and fever (9.5%) were not common. Laminaria tent insertion plus sulprostone infusion was an effective and safe regimen for second-trimester termination of pregnancy with live fetuses.

Prevalence and molecular characterization of beta-thalassemia in Filipinos

Beta-thalassemia (thal) is a common single-gene disease worldwide. However, the prevalence of beta-thal and the spectrum of beta-globin gene mutations in Filipinos remain unclear. This study sought to answer these two questions. A total of 2954 apparently healthy Filipinos in Taiwan were recruited for a prevalence study. A complete blood count was done in every subject. Those with microcytosis were studied with hemoglobin (Hb) high-performance liquid chromatography to determine the levels of Hb A2 and Hb F. Twenty-seven subjects had elevated levels of Hb A2 (>4.0%). These 27 suspected beta-thal carriers and another 16 beta-thal major patients who were being treated in the Philippines were studied to determine the spectrum of beta-globin gene mutations. Gap-PCR was used to detect the Filipino deletion of beta-thal, and direct sequencing was used to detect point or small mutations in the beta-globin gene. All of the 27 suspected beta-thal carriers had one mutation in the beta-globin gene, resulting in an overall prevalence of 0.9%. The spectrum of beta-thal mutations was similar in the carrier and patient groups. Analysis of the pooled identified seven different mutations in the study population. The Filipino deletion was the most common mutation, accounting for 45.8% (27/59) of the alleles, followed by codon 67 (-TG) (16 alleles), and Hb E (11 alleles). These three mutations accounted for 92% of the Filipino beta-thal alleles. Elucidation of the beta-thal mutations in Filipinos is useful for the genetic counseling and prenatal diagnosis of this disease.

Fluorescence microsatellite analysis to study the parental origin of the supernumerary chromosome in Down's syndrome

OBJECTIVE

Down's syndrome (DS) is an important cause of mental retardation. This study investigated the parental origin of the extra chromosome 21 in DS patients.

METHODS

Fourteen families each with a DS patient were recruited for analysis of nine microsatellite markers on chromosome 21. We collected DNA from both parents and the patient and used polymerase chain reaction to amplify nine segments on chromosome 21: D21S1435, D21S1436, D21S1437, D21S1446, D21S156, D21S258, D21S263, D21S265 and D21S270. One of each pair of DNA primers was labeled with a fluorescence dye. The amplified products were subjected to electrophoresis in a semi-automated DNA sequencer and then analyzed with Genescan software to determine the origin of the extra chromosome 21.

RESULTS

The extra chromosome 21 originated from the mother in 13 (93%) patients and from the father in one (7%) patient.

CONCLUSIONS

Our findings were compatible with those from Caucasian patients. A great majority of Down's syndrome cases resulted from meiotic errors in the eggs.

Congenital adrenal hyperplasia. Molecular characterization

OBJECTIVE

To study the molecular defects of congenital adrenal hyperplasia (CAH).

STUDY DESIGN

Twenty Chinese patients, including 8 with salt-wasting (SW) type CAH, 11 with simple virilizing (SV) type CAH and 1 with nonclassical (NC) type CAH, were recruited. Two rounds of the polymerase chain reaction (PCR) were used to study the 21-hydroxylase gene (CYP21). The primary PCR amplified CYP21-specific DNA fragments, and the secondary PCR used products from the primary PCR for analysis of amplification-created restriction sites (ACRS) and direct DNA sequencing. In all patients, ACRS analysis was done at 12 possible mutation sites, and then direct DNA sequencing was performed to confirm or define the molecular defects.

RESULTS

Ten different mutations, including nine point mutations and gross gene deletion or conversion, were found in this study. Of the nine point mutations, eight could be easily detected by ACRS analysis. The three most common mutations were codon (CD)172 t-->a (I172N), IVS-II 656 c/a-->g, and gross gene deletion or conversion, accounting for 27.5% (11/40 alleles), 25% (10/40) and 20% (8/40) of all identified mutations, respectively. All SW patients were compound heterozygotes of IVS-II 656, gross gene deletion or conversion, or other severe defects, including CDs236 (t-->a) (I236N)+ 237 (t-->a) (V237E)+ 239 (t-->a) (M239K), CD306 (+t), CD318 (c-->t) (Q318X) and CD356 (c-->t) (R356W) mutations. All SV patients had one allele with a CD172 (I172N) mutation. One allele of an NC patient had a CD183 (c-->g) (D183E) mutation, and the other allele was not defined. In the whole series, four alleles (10%) had more than one mutation.

CONCLUSION

We found 10 different mutations in this study. The correlation between genotypes and phenotypes was compatible with the reported data. Two rounds of PCR and ACRS analysis may provide important information for genetic counseling, prenatal diagnosis and management of families at risk for CAH.

Molecular characterization and PCR diagnosis of Thailand deletion of alpha-globin gene cluster

Thailand deletion of alpha-Thalassemia (thal) 1 involves the zeta2-, phi zeta1-, alpha2-, alpha1-, and theta1-globin genes. In Southeast Asians and Taiwanese, this mutation is the second most common long-segment deletion of two alpha-globin genes, after the Southeast Asian deletion. To define the Thailand deletion breakpoints, we used polymerase chain reaction (PCR) to amplify the normal-sequence DNA fragments across the breakpoints. The amplified products were sequenced directly or after cloning into pGem-3Z or pCR2.1 vectors. Comparison of the normal and mutant sequences revealed that the 5' breakpoint lies between nucleotides 1,269 and 1,290 upstream of the initiator codon adenine of the zeta2-globin gene, and the 3' breakpoint lies between nucleotides 29,387 and 29,408 downstream of it. A total of 30,677 nucleotides were deleted. Both breakpoints mentioned above lie within the Alu repetitive sequences and an extensive sequence homology is present around the two breakpoints. These findings suggest that homologous recombination is the mechanism by which the deletion occurs. Based on our data, we used three oligonucleotide primers to amplify the regions across the deletion and its corresponding normal sequence. The feasibility of PCR diagnosis was confirmed in 20 carriers with this deletion.

Molecular study and prenatal diagnosis of alpha- and beta-thalassemias in Chinese

Thalassemia is one of the most common single gene diseases worldwide. Populations in southern China and Taiwan have high prevalence rates of alpha- and beta-thalassemias. This review summarizes the current status of molecular studies, carrier screening, and prenatal diagnosis of thalassemia in Chinese. There are three genotypes of alpha-thalassemia 1 and at least six of alpha-thalassemia 2 in Chinese. For alpha-thalassemia 1, the South-East Asian deletion is the most common, followed by the Thai then Philippino deletions. For alpha-thalassemia 2, the rightward deletion is the most common, followed by the leftward deletion, and the nondeletional defects Hb Constant Spring and Hb Quong Sze. Twenty-eight different beta-thalassemia mutations have been reported. Four mutations, IVS-II-654 (C-->T), codons 41/42 frameshift (-TCTT), and nonsense codons 17 (A-->T) and -28 (A-->G), account for more than 90% of mutant alleles. For detection of alpha-thalassemia, polymerase chain reaction-related techniques are mainly used. Southern blot hybridization is still useful, especially for prenatal diagnosis. For detection of beta-thalassemia mutations, analysis of amplification-created restriction sites and reverse dot blot hybridization have been extensively used. In Taiwan, a national screening program incorporating hematological and molecular biological methods for thalassemia detection in pregnant women has been in progress for 5 years. Prenatal diagnosis has been performed in more than 1,800 pregnancies, including 1,500 cases at risk for homozygous alpha-thalassemia 1 and 300 for beta-thalassemia major, resulting in early prenatal diagnosis and termination of pregnancies affected with homozygous alpha-thalassemia 1 and an approximately 70% decrease in the number of newborns affected with beta-thalassemia major. In mainland China, only one large-scale screening program is in place. Characterization of undefined alleles, a higher awareness of the disease among physicians and the general public, and improvement of the service network will be important for early prenatal diagnosis and prevention of the disease in the future.

Complete androgen insensitivity syndrome. Molecular characterization in two Chinese women

OBJECTIVE

To study the molecular basis of complete androgen insensitivity syndrome (AIS).

STUDY DESIGN

The coding region of the human androgen receptor (hAR) gene in two women with AIS was amplified with polymerase chain reaction using 12 pairs of oligonucleotide primers and then sequenced with a dye terminator method.

RESULTS

Both patients had mutation in exon E of the androgen-binding domain. In one patient, codon 732 GAC (aspartic acid) was changed to ACC (asparagine), and her CAG polyglutamine tract had 27 repeats. In the other patient, codon 765 GCC (alanine) was changed to ACC (threonine), and her CAG polyglutamine tract in exon A had 19 repeats.

CONCLUSION

Except for CAG polyglutamine polymorphism, these two missense mutations were the only differences detected in the coding region of the hAR gene. Both mutations involved the CpG sequence, which has been regarded as a mutation hotspot. To the best of our knowledge, these two mutations have not been observed before in Chinese women. Elucidation of the molecular defects of AIS patients would be very helpful for genetic counseling and prenatal diagnosis.

Misdiagnosis of homozygous alpha-thalassaemia 1 may occur if polymerase chain reaction alone is used in prenatal diagnosis

The polymerase chain reaction (PCR) is a quite sensitive diagnostic tool but its specificity may be hampered because of contamination of foreign DNA. In order to determine the diagnostic accuracy of PCR in diseases due to gross gene deletion, a total of 180 fetuses at risk of homozygous South-East Asian deletion (SEA) of alpha-globin genes were included for study. Both PCR and Southern hybridization (SH) were performed. By PCR, three of 43 affected fetuses were misdiagnosed as heterozygotes; four of 50 normal fetuses were misdiagnosed as heterozygotes; and four of 87 heterozygotes were misdiagnosed, two as normal and two as affected. Misdiagnosis in affected and normal fetuses was most likely due to maternal DNA contamination, while misdiagnosis in heterozygotes was probably due to a failed PCR. In the experiments with PCR in which we added DNA from a carrier woman to an affected or a normal fetus, a level of 1/64 and 1/16 contamination resulted in the appearance of normal and SEA breakpoint sequences, respectively. In the SH experiments using artificially contaminated DNA, a level of 1/4 contamination showed the normal and SEA bands, respectively, while a contamination level lower than 1/8 and 1/16 respectively did not reveal contamination bands. The high sensitivity of PCR makes it easier to amplify contaminated DNA. For accurate prenatal diagnosis, PCR should be performed very carefully and SH seems to be a useful back-up.

Molecular characterization of beta-thalassemia in Taiwan and the identification of two new mutations

Polymerase chain reaction-based techniques were used to study the molecular defects of 480 unrelated beta-thalassemia heterozygotes in Taiwan. Analysis of artificially created restriction sites and gap-polymerase chain reaction were performed to detect four common mutations, i.e. IVS-II-654 (C-->T), codons 41/42 (-TCTT), codon 17 (A-->T), -28 (A-->G), and a deletional form of delta beta-thalassemia in the Chinese population. In cases with negative or ambiguous results with the aforementioned methods, direct DNA cycle sequencing using either S35-dATP or a fluorescent dye terminator, was carried out to determine the defects. A total of 14 different mutations have been found in this series. The IVS-II-654 mutation was the most common (39.6%), followed by the codons 41/42 mutation (37.9%). The four common genotypes accounted for 92.3% of defects. Two new mutations were detected: codon 31 (-C) and codons 40/41 (+T). Both defects resulted in a frameshift and a premature terminator, the former at codon 60, the latter at codon 43. Although we have studied our cases extensively, the molecular defects in seven alleles are still unknown.

Leiomyosarcoma of the pulmonary vein

OBJECTIVE

We report a case of leiomyosarcoma (LMS) of the pulmonary vein and comment on the natural history and determinants for survival for this rare condition.

EXPERIMENTAL DESIGN

Our retrospective review is only the fourth such case reported in the world's literature.

SETTING

A teaching hospital with an active surgical residency program. PATIENT OR PARTICIPANT: A 61-year-old female who presented with a central pulmonary mass.

INTERVENTIONS

Complete resection without pneumonectomy of cardiopulmonary bypass. Pathology showed low grade LMS.

MEASURES

Determinants for survival include complete surgical resection and a low mitotic activity of the tumor.

RESULTS

The patient remains no evidence of disease three years following initial treatment.

CONCLUSIONS

One reported case of LMS of the pulmonary vein had favorable determinants for survival; complete surgical resection and low mitotic activity of the tumor. These factors may have contributed to the successful outcome. The natural history of LMS of the pulmonary vein appears similar to the more widely studied LMS of the inferior vena cava.

Norplant subdermal contraceptive system: experience in Taiwan

From November 1988 to December 1994, a total of 567 female volunteers were enrolled in Norplant implant studies at the National Taiwan University Hospital. After a median follow-up of 29 months, only 3 of the 529 available cases became pregnant (a cumulative rate of 1.2 pregnancies per 100 users over 5 years). Chromosome analysis of 2 of the 3 abortuses revealed 46,XX/46,XX,inv(3) and 46,XX. Menstrual problems were the most common adverse effects and were also the main reason for discontinuation (65%, 108/166). The continuation rate was 90%, 78%, 70%, 61%, and 42% at the end of 1, 2, 3, 4, and 5 years after insertion, respectively. In the 21 patients who wished to become pregnant, fertility recurred soon after removal of the Norplant implants. The data suggested that the Norplant implants system is a highly effective, safe, and long-acting method of reversible contraception. It would be worthwhile to introduce this contraceptive system to Taiwan's family planning program.

In vitro fertilization pregnancy achieved with epididymal caput sperm of a patient with obstructive azoospermia

A successful epididymal sperm aspiration, in vitro fertilization and embryo transfer in a woman whose husband had previously undergone extensive attempts at recanalization of the spermatic ducts is reported. A twin pregnancy was achieved using sperm obtained from the husband's epididymal caput. This case demonstrates that pregnancy can be achieved by this reproductive technique in cases of obstructive azoospermia, even after extensive surgery.

Prenatal diagnosis by transabdominal chorionic villus sampling in the second and third trimesters

From October 1989 through December 1993, 124 pregnant women (114 in the second trimester and 10 in the third trimester) underwent transabdominal chorionic villus sampling (CVS) for prenatal molecular or cytogenetic diagnosis. The mean gestational age was 18.2 weeks. Indications for CVS comprised single gene disease (72%), fetal anomalies detected by ultrasound (17%), advanced maternal age (6%), and previous siblings with chromosomal aberration (5%). Among the 89 fetuses at risk for single gene disease, 20 were diagnosed as affected by DNA analysis. Among the 35 fetuses at risk for chromosomal anomaly, 4 had trisomy, 3 had a 45,XO karyotype and 2 had a structural chromosomal abnormality. The miscarriage rate was 1.8% (2/114) and the spontaneous preterm birth rate was 2.4% (3/124). No maternal or other fetal complications occurred. This study suggested that second- and third trimester CVS is a safe and useful method for prenatal diagnosis.

Ultrasonographic scanning of placental thickness and the prenatal diagnosis of homozygous alpha-thalassaemia 1 in the second trimester

In order to evaluate the association between placental thickness (PT) and fetal homozygous alpha-thalassaemia 1 before the appearance of classic ultrasound findings of haemoglobin (Hb) Bart's hydrops fetalis, a total of 473 pregnancies were collected. The control group included 422 normal pregnancies with a gestational age from 14 to 23 weeks and the study group included 51 affected fetuses in the same gestational period. Fetal biparietal diameter (BPD) and PT were measured by high-resolution ultrasound. PT was evaluated against BPD. In the control group, the PT generally increased in parallel with the advancement of gestational age. All PT measurements in the study group were above the mean PT of their respective gestational week in the control group. Forty-six (90 per cent) of the pregnancies in the study group had PT larger than the mean plus two standard deviations of the control group. This study suggests that ultrasound measurement of PT may be a useful aid in the prenatal diagnosis of Hb Bart's hydrops fetalis before its classic findings become apparent in the late second trimester or third trimester.

Prenatal diagnosis of 46,XX/47,XXY mosaicism: a case report

A case of 46,XX/47,XXY mosaicism was diagnosed at 22 gestational weeks by amniocentesis and fetal blood sampling. After genetic counselling, the couple elected to have the pregnancy terminated. Culture of the fetal skin and both gonads confirmed the prenatal diagnosis. In external appearance, the abortus had no remarkable findings except hypospadia. Histology of both gonads showed testicular tissue without evidence of ovarian components.

Recurrent Down's syndrome due to maternal ovarian trisomy 21 mosaicism

A family with three children who had Down's syndrome and one healthy child is reported. Cytogenetic studies of the peripheral blood revealed trisomy 21 in the affected children, and normal karyotypes in both the parents and the healthy child. However, a biopsy of the mother's right ovary showed a mosaic trisomy 21 cell line (8/20 cells). By DNA polymorphism analysis, segregation of trisomy oogonia appeared to be the cause of recurrent trisomy 21.

Infrequent mutation in tumor suppressor gene p53 in gestational trophoblastic neoplasia

In order to determine the p53 status of gestational trophoblastic neoplasia, 24 cases of molar pregnancies and two choriocarcinoma cell lines (JAR and JEG-3) were evaluated for the presence of mutations. The evaluation involved the whole coding sequence (i.e. exons 2-11) of the p53 gene with polymerase chain reaction (PCR) amplification of genomic DNA, followed by single strand conformation polymorphism (SSCP) and sequencing. Only one case of hydatidiform mole was found to have a missense point mutation (codon 295, CCT-->CTT, i.e. proline to leucine) of the p53 gene. The results suggest that p53 mutation is rarely involved in the pathogenesis of gestational trophoblastic neoplasia.

Cytogenetic study of spontaneous abortions with the Giemsa banding method

Among 102 spontaneous abortuses karyotyped, 29 were from parents with a history of unexplained recurrent spontaneous abortion (group A), and 73 were from parents without a history of recurrent spontaneous abortion (group B). The mean maternal ages of these two groups were not significantly different. The chromosomal aberration rate in group A was 48.3% and in group B was 53.4%. The difference was not significant. The most common chromosomal anomaly was autosomal trisomies in both groups, while monosomy X was more common in group B. The subsequent spontaneous abortion rate was also not significantly different between the two groups.

Increased level of second trimester maternal serum chorionic gonadotropin in pregnancy with a fetus affected by homozygous alpha-thalassemia 1

With enzyme immunoassay, maternal serum chorionic gonadotropin (MShCG) level was determined in 58 pregnancies affected with fetal homozygous alpha-thalassemia 1. In 40 pregnancies with a gestational age of 10 to 14 weeks, 8 (20%) had an MShCG level above 2.5 multiples of the median (MoM); while in the other 18 pregnancies with a gestational age of 15 to 23 weeks, 14 (78%) had a level above 2.5 MoMs and none had a level below the median. Homozygous alpha-thalassemia 1 of the fetus was associated with an elevated MShCG. Therefore in second-trimester screening for Down's syndrome by measurement of MShCG, homozygous alpha-thalassemia 1 should also be considered if elevated MShCG levels are found.

Prevalence and molecular studies of thalassemia in five aboriginal groups in Taiwan

A total of 1,342 blood samples from five aboriginal groups in Taiwan, comprising 522 of the Ami, 246 of the Bunum, 227 of the Atayal, 214 of the Paiwan and 133 of the Yami group, were collected. A complete blood count was performed in each case. In subjects with a mean corpuscular volume < 85 fl or hemoglobin (Hb) < 12 gm% (female) or 13 gm% (male), quantitation of Hb A2 and DNA analysis of alpha- and beta-globin genes were performed. Alpha-thalassemia was diagnosed by Southern hybridization of subject's DNA to alpha-, and zeta-globin gene fragments, and to Lo probe if needed. DNA from beta-thalassemia carriers was studied by polymerase chain reaction and direct sequencing. In the Ami, 42 (8.2%) were alpha-thalassemia 1 carriers, 42 (8.2%) were alpha-thalassemia 2 carriers, one had Hb H disease, and four (0.8%) were beta-thalassemia carriers. In the Bunun, one (0.2%) was an alpha-thalassemia 1 carrier, and two (0.4%) were alpha-thalassemia 2 carriers. In the Atayal, one (0.2%) was an alpha-thalassemia 1 carrier. In the Paiwan, seven (3.3%) were alpha-thalassemia 1 carriers, and one (0.5%) was an alpha-thalassemia 2 carrier. In the Yami, none were either alpha- or beta-thalassemia carriers. Diverse genetic origin, intragroup breeding and malarial selection may play a role in the significant differences of thalassemia prevalences both between the Chinese and the aborigines, and among different groups of aborigines.

Amniocentesis in mothers who are hepatitis B virus carriers does not expose the infant to an increased risk of hepatitis B virus infection

Sixty-seven pairs of mothers with hepatitis B virus (HBV) surface antigen (HBsAg) and their infants were divided into two study groups to determine the effect of amniocentesis on intrauterine HBV infection. In the first study group (35 pairs), the infant's HBsAg status in cord blood was studied and the results were compared with those obtained in the cord blood from 65 infants born to HBsAg-positive women who did not have an amniocentesis. In the second study group (32 pairs), the HBV status of the infants was studied at the age of three months to five years and compared with the HBV status of 3,454 infants in the National HBV Prevention Program. In the first study group, one sample (2.9%) was weakly positive for HBsAg; while in the first control group, two (3.1%) were positive. In the second study group, three (10%) infants were positive for HBsAg. The failure rates of immunoprophylaxis in the second study and control groups were similar (9.4% vs 11% for HBsAg carrier mothers; 30% vs 14% for HBe antigen-positive carrier mothers). This suggested that genetic amniocentesis did not increase the risk of intrauterine HBV infection.

Prenatal diagnosis of X-linked hydrocephalus in a Chinese family with four successive affected pregnancies

We report on a woman with four successive pregnancies affected with X-linked hydrocephalus (XLH). The first child had prenatal craniocentesis and died in utero. The second child had a postnatal shunting operation, but suffers from severe growth and mental retardation at 5 years of age. In the third pregnancy, prenatal ultrasound detected hydrocephalus at the 16th and 20th weeks of gestation and the pregnancy was terminated. In the fourth pregnancy, ultrasound scanning at the 17th and 20th weeks of gestation revealed no remarkable findings, but hydrocephalus was detected at the 24th week. Autopsy confirmed the prenatal diagnosis. DNA polymorphism analysis of the Bc1I site of exons 17-18 of factor VIII gene of the woman and her last two fetuses seemed to be compatible with a linkage between the XLH locus and factor VIII gene. Although XLH has a variable presentation of ventriculomegaly, ultrasound scanning is still a useful tool for prenatal diagnosis at present. Earlier and more accurate prenatal diagnosis will be feasible with molecular analysis of the XLH locus or its flanking regions.

Alpha-thalassemia in the four major aboriginal groups in Taiwan

A total of 1309 unrelated blood samples from four major Taiwan aboriginal groups, including 522 of the Ami, 246 of the Bunun, 227 of the Atayal, and 214 of the Paiwan groups, were collected. Subjects with a mean corpuscular volume below 85 fl and Hb A2 values below 3.5% were further studied with Southern hybridization to determine the status of alpha-globin genes. In the Ami, 43 (4.1%) chromosomes had alpha-thalassemia 1 and 43 (4.1%) had alpha-thalassemia 2. Of the 43 alpha-thalassemia 1 chromosomes, 33 were of the Thailand, one of the Philippine, and nine of the Southeast Asian deletion. Of the 43 alpha-thalassemia 2 chromosomes, 42 were of the type I rightward deletion and one was of leftward deletion. In the Bunun group, one chromosome (0.2%) was of the Thailand deletion and two (0.4%) were of type I rightward deletion. In the Atayal group, only one chromosome (0.2%) was of the Philippine deletion. In the Paiwan group, four chromosomes (0.9%) were of the Southeast Asian deletion and three (0.7%) were of the Thailand deletion. Among the four groups, the Ami had the highest prevalence of alpha-thalassemia, which was also higher than that of the Chinese living in Taiwan.

Intrauterine death of co-twin in the third trimester: a case report of twin-to-twin transfusion syndrome and cord accident

Intrauterine death of one twin in a monochorionic twin pregnancy is associated with increased mortality and morbidity of the survivor. The exact cause is usually difficult to determine even after delivery. The choice of management for the mother and the viable co-twin is difficult. We report on a case of intrauterine death of one twin with monochorionic placentation. Twin-to-twin transfusion syndrome was suggested by the sonographic findings and evidence of a vascular communication. The co-twin survived for another 39 days without complications after the diagnosis of fetal death. Postmortem examination showed severe torsion and constriction of the umbilical cord at the fetal end with focal deficiency of Wharton's jelly. It is likely that torsion and constriction of the cord was responsible for the one intrauterine fetal death; this so-called "twist amputation" of the cord, on the other hand, contributed to the favorable outcome in the surviving co-twin.

Surface characterization and platelet adhesion studies of plasma-sulphonated polyethylene

Canine platelet adhesion on sulphur dioxide and allyl phenyl sulphone plasma-treated low density polyethylene (LDPE) was studied. Both 5 W plasma excitation energy-treated surfaces showed the highest S:C atomic ratio by ESCA analysis. Surface hydrophilicity increased drastically after plasma treatment. However, surface hydrophilicity decreased with time. This might be due to the diffusion of the hydrophilic functional groups into the bulk of the material and/or the migration of low molecular weight hydrocarbon species into the surface region. The allyl phenyl sulphone plasma-treated LDPE was less platelet-activating in terms of platelet adhesion and spreading and was independent of the different plasma excitation energy levels used. Sulphur dioxide plasma-treated LDPE showed a higher level platelet activation than the untreated LDPE. Among the sulphur dioxide plasma-treated LDPE samples, the sample prepared using the 5 W excitation energy was less platelet-activating than the samples treated by higher plasma excitation energies.

Norplant-2 subdermal contraceptive system: experience in Taiwan

Subdermal Norplant-2 implantation, developed for contraception based on sustained release of levonorgestrel, has already been conducted in many countries around the world. From October 1986 to November 1988, a total of 267 female volunteers were enrolled in Norplant studies at the National Taiwan University Hospital. After a follow-up of 36 months, only one of the 231 evaluable cases (0.4%) became pregnant. The continuation rate was 84.5%, 61.3%, and 52.0% at the end of 12, 24 and 36 months after insertion, respectively. Menstrual problems were the most common adverse effects and were also the main reason for discontinuation. In the 23 patients who wished to become pregnant, fertility occurred soon after removal of the Norplant implant. After insertion, serum total cholesterol and triglyceride levels significantly decreased and the hemoglobin concentrations were increased. No liver or renal toxicities were detected. The data suggest that Norplant-2 is a highly effective, safe and long-acting method of reversible contraception. It would be worthwhile to introduce this contraceptive system into Taiwan's family planning program.

Prenatal diagnosis of Hb H disease due to compound heterozygosity for South-east Asian deletion and Hb constant spring by polymerase chain reaction

A pregnant woman has two children affected by moderately severe Hb H disease due to compound heterozygosity of South-east Asian deletion and Constant Spring mutation. In her third pregnancy, transabdominal chorionic villus sampling was performed at the tenth gestational week to obtain fetal DNA. The polymerase chain reaction was used for detection of both the South-east Asian deletion and the Constant Spring mutation. Hb H disease was diagnosed in the fetus. After genetic counselling, the couple elected to have the pregnancy terminated.

Rapid detection of human hemoglobin Quong Sze by polymerase chain reaction

Human hemoglobin Quong Size is a nondeletional defect involving codon 125 of the alpha 2-globin gene. The molecular defect is a T to C mutation, therefore, a new MspI site (CCGG) is created. Using a pair of flanking DNA primers and polymerase chain reaction, a DNA fragment of 339 basepairs (bp) was amplified. After MspI restriction and gel electrophoresis, the mutation could be clearly identified by the presence of two fragments, 108 and 123 bp. This method is rapid and simple and will be very useful in the genetic counseling of Southeast Asians, including the Chinese, in which nondeletional alpha-thalassemia defects are common.

Rapid detection of Chinese G gamma+(A gamma delta beta)zero-thalassemia by polymerase chain reaction

The Chinese G gamma+(A gamma delta beta)zero-thalassemia is caused by a deletion of more than 80 kilobases. It has a beta(+)-thalassemia phenotype and should be differentiated from other mutations causing beta-thalassemia. Using polymerase chain reaction with three oligonucleotide primers bridging the breakpoints, the deletion can be detected easily. The method is useful in the genetic counseling and prenatal diagnosis of the at-risk families.

Rapid prenatal determination of fetal sex by polymerase chain reaction on amniocyte DNA

Sex determination in early gestation is important for fetuses at risk for X-linked disorders or congenital adrenal hyperplasia. One hundred and seventy consecutive samples of amniocytes were collected between the 12th and 31st gestational week. Seven women received early amniocentesis before the 14th week. Fetal sex was determined by amplification of Y-specific DNA fragments within five hours. All results of the polymerase chain reaction, except for one false-negative, were compatible with cytogenetic analyses. Polymerase chain reaction of amniocyte DNA provides a rapid technique for sex determination in early gestation with high specificity and sensitivity.

Combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization and embryo transfer: report of a case

A case of combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization (IVF) and transfer of six embryos is presented. The case was diagnosed as intrauterine triplets ultrasonographically at seven weeks of gestation. Unfortunately, the patient suffered from severe lower abdominal pain and hypovolemic shock at 10 weeks of gestation, and an emergent laparotomy was done. During the operation, a ruptured cornual pregnancy with accompanying hemoperitoneum was found. Because fetal heart beats were not detected by intraoperative ultrasonography in the other two intrauterine fetuses, evacuation of the gestational contents through the uterine defect was done, and the rupture site was repaired. The incidence, mechanism and management of heterotopic pregnancies after in vitro fertilization and embryo transfer are discussed.

Dystrophin gene deletion in Chinese Duchenne/Becker muscular dystrophy patients via multiplex DNA amplification

Duchenne/Becker muscular dystrophy (DMD/BMD) is a progressive muscle-wasting disease. The dystrophin gene responsible for the disease is the largest human gene ever cloned and is prone to gross gene deletion in two "hot spot" regions. Using nine pairs of oligonucleotide primers deduced from the two regions, we have screened 23 unrelated Chinese DMD/BMD patients by multiplex polymerase chain reaction. Nine (39%) patients were noted to have gene deletion, one in the 5' terminus and eight in the distal half of the gene. The incidence is similar to that reported in other large series mainly on Caucasian patients. The "hot-spot" regions also seem to be present in Chinese patients. Multiplex gene amplification for deletion analysis is useful in the diagnosis of patients with neuromuscular diseases and is an important aid in the prenatal diagnosis and genetic counseling of at-risk families.

Hydrops fetalis caused by severe alpha-thalassemia

Alpha-thalassemia is a prevalent condition in South East Asia and spreading because of increasing immigration. Hemodynamic study of Hb Bart's hydrops fetalis, the most severe form of alpha-thalassemia, showed the fetuses were in a hyperdynamic circulatory state and were also more acidotic, hypoxic, and hypercarvic than normal fetuses. The most common molecular defects of Hb Bart's hydrops fetalis was the Southeast Asia type deletion. Prenatal diagnosis of Hb Bart's hydrops fetalis and HbH diseases has been achieved using chorionic villi sampling or fetal blood sampling.

Pericentric inversions of chromosome 9 in Taiwanese fetuses

Using trypsin-Giemsa banding, a total of 1,350 unrelated Chinese fetuses were studied for pericentric inversion of chromosome 9 [inv(9) (p11; q13)]. Sixteen cases (1.2%) were found to have this variant. The prevalence was higher than that in a previous report on Asians. All the fetuses with inv(9) were born with a normal phenotype.

Prenatal cytogenetic diagnosis in amniocentesis

From 1982 to 1990, cytogenetic studies were successfully conducted in 2,975 (96.19%) of the 3,096 pregnant women who underwent amniocentesis. The average maternal age was 33.7 years and the average gestational age was 18.1 weeks. Common indications of amniocentesis included advanced maternal age (AMA) (54.76%), previous fetus with chromosomal aberrations (6.82%) or gross anomalies (5.01%), intrauterine gross anomaly (4.97%) and maternal exposure to drugs or radiation (5.28%). Among the 89 cases (2.99%) with detected chromosomal aberrations, 53 were numeric (31 trisomies, 21 sex chromosome aberrations and one tripoidy) and 36 were structural (six de novo and 30 hereditary structural rearrangement). The incidence of chromosomal aberrations was 2.03% in cases with AMA. While only four of the 143 cases with previous fetal trisomy 21 had recurrence, the recurrent rate was 90.91% in 11 cases with previous fetal chromosomal translocation. Thirty (20.27%) of the 148 cases with abnormal sonograms showed chromosomal aberrations. Certain congenital anomalies are closely associated with cytogenetic changes: duodenal atresia and trisomy 21; cystic hygroma and 45,X; and polyhydramnios and trisomy 18. Only two of the 157 cases with indications of drug or radiation exposure had abnormal cytogenetic studies. Two of the 53 cases with detected numerical aberrations (47,XXY and 47,XXX) and 27 cases with hereditary structural rearrangement elected to continue their pregnancies. All of these babies were delivered without gross anomalies. This study suggests that for prenatal diagnosis. However, complementary measures, such as routine antenatal ultrasound and maternal serum alphafetoprotein, should be added to increase the efficacy of genetic amniocentesis.

Carrier detection and prenatal diagnosis of alpha-thalassemia of Southeast Asian deletion by polymerase chain reaction

Alpha-thalassemia of Southeast Asian deletion (-- SEA/) is very common in Southeast Asia. Homozygosity of this genotype is the major cause of Hb Bart's hydrops fetalis in Taiwan. With polymerase chain reaction using three oligonucleotide primers bridging the common deletion breakpoint, a DNA fragment of 194 basepairs (bp) was amplified in chromosomes with the -- SEA determinant and a DNA fragment of 287 bp was amplified in chromosomes without this deletion. In our pilot study including 8 normal subjects, 20 obligate carriers, and 11 homozygotes of the deletion, all the genotypes were determined and then confirmed by Southern blotting and DNA hybridization with phi zeta globin gene probe. For prenatal diagnosis, 55 at-risk pregnancies were collected. Chorionic villus sampling was done in 51 cases and early amniocentesis was done in 4 cases. Fourteen cases (25.5%) were diagnosed as normal, 25 (45.5%) as heterozygotes, and 16 (29%) as homozygotes of -- SEA. All of the diagnoses were also confirmed as aforementioned. With polymerase chain reaction, the determination of the -- SEA deletion is straightforward and is much quicker and easier than with conventional Southern blotting and DNA hybridization. In areas with a high prevalence of -- SEA deletion, this method provides a rapid tool for carrier detection and prenatal diagnosis.

Molecular characterization of severe alpha-thalassemias causing hydrops fetalis in Taiwan

alpha-Thalassemia hydrops fetalis is a common disorder in Taiwan. The condition causes perinatal death and many maternal obstetrical complications. In order to determine the molecular defects of this condition in Chinese, 87 unrelated families with this disorder were collected in the past 4 years. The molecular defects were studied by Southern blotting and DNA hybridization with phi zeta 1-globin gene and LO (a 0.4 kb BamHI/EcoRI fragment in the 5' flanking region of the zeta 2-globin gene) probes. Eighty-one (93.1%) fetuses had homozygous Southeast Asian deletion (- -SEA/- -SEA). Five (5.7%) fetuses were compound heterozygotes for the Southeast Asian deletion and Thailand deletion (- -SEA/- -THAI). The remaining fetus was a compound heterozygote for the Southeast Asian deletion and an uncharacterized nondeletional defect (- -SEA/(alpha alpha)Th). The molecular defects of alpha-thalassemia hydrops fetalis in Chinese are heterogeneous. This fact has important implications for genetic counseling and prenatal diagnosis.

Antenatal ultrasonic findings of craniofacial malformations

Fetal craniofacial malformations were identified sonographically in 13 cases. Holoprosencephaly and median cleft syndrome were the most frequent findings. Cleft lip, cleft palate, single nostril, cyclopia and hypotelorism were also seen. Seven of the 13 cases (54%) had polyhydramnios. Amniocentesis was performed on 12 fetuses, and 5 of them showed autosomal trisomy. Accordingly, when craniofacial malformation is recognized antenatally, a careful survey of the fetus for other associated structural anomalies and cytogenetic study are indicated to aid in diagnosis and subsequent obstetric and neonatal management. Also screening for fetal craniofacial malformation is recommended during mid-trimester ultrasound examinations.

Selective reduction of multiple pregnancies in the first trimester or early second trimester

Nine cases of multiple pregnancies, including 7 sets of triplets and 2 sets of quadruplets, were enrolled for selective fetal reduction between March 1989 and July 1990 at the National Taiwan University Hospital. Under transabdominal or transvaginal ultrasound guidance, potassium chloride was injected into the fetal cardiac chamber to kill the selected fetus during the 10-14th gestational week. The number of fetuses was reduced to two in all cases. No maternal complications occurred during the procedure. Six gravidas have given birth to 6 sets of healthy twins; two pregnancies are progressing smoothly at 26 and 23 weeks of gestation, respectively, and one case underwent spontaneous abortion 4 weeks after the procedure. Selective fetal reduction under ultrasound guidance is an acceptable method of preventing high perinatal mortality and morbidity of immature fetuses in grand multiple pregnancies.

Detection of beta-globin gene mutations by polymerase chain reaction

The polymerase chain reaction and oligonucleotide probe hybridization technique were applied to the detection of two common mutations of the beta-globin gene found in Chinese, namely the 4-base pair deletion at the 41-42 codons and the C to T substitution at nucleotide 654 of IVS-2. The accuracy of the method was established using beta-thalassemia cases with known mutations or haplotypes of the restriction fragment length polymorphism (RFLP). A further 11 cases of thalassemia intermediate and thalassemia minor were then analysed with the same approach. Our results showed that 5 of the 11 cases carried the TCTT-deletion at codons 41-42. Our method is economical both in terms of materials and time needed and in an alternative to the use of the molecular RFLP approach in the prenatal diagnosis of beta-thalassemia.