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S Kanokpongsakdi

Publications and source records attributed to S Kanokpongsakdi.

11 recordsLinked to original sources
PubMed2001

A family at risk of congenital adrenal hyperplasia: a molecular approach for prenatal diagnosis.

The molecular method for prenatal diagnosis in the first trimester was carried out on the second and third pregnancies of a family at risk of congenital adrenal hyperplasia (CAH). The first child, an 8-year-old daughter, was affected. The molecular and cytogenetic prenatal diagnosis on the second pregnancy revealed that the fetus which was a female had been affected. The pregnancy was then terminated. The couple presented with the third pregnancy at 8 weeks' gestation. The same approach revealed that the fetus, a male, was affected. The couple opted for continuation of pregnancy which was on-going at the time of the manuscript preparation. To our knowledge, this is the first family in Thailand who had molecular approach for prenatal diagnosis of CAH. This approach allows early information about the fetal status of the disease and, together with the result of fetal gender, will help early decision making in pregnancy management.

Adrenal Hyperplasia, Congenital↗
PubMed2000

Charts of Thai fetal biometries: 2. Biparietal diameter.

A cross-sectional study was conducted in order to construct a new reference chart for Thai fetal biparietal diameter (BPD). A total of 621 normal pregnant women between 12-41 weeks of gestation and their fetuses were recruited. Measurements were made once at a randomly assigned gestational age specifically for the purpose of this study only. Due to unfavorable fetal position in some cases, BPD data were available in 613 measurements. Linear regression models were fitted separately to estimate the mean and standard deviation as functions of gestational age. Reference centiles were constructed from both equations, assuming the data were normally distributed. A new reference centiles chart for BPD is presented and compared with previously published data. Our derived centiles were clearly lower than those from Western studies showing the importance of racial differences between populations. This elucidates the need to develop fetal biometries charts specifically for each region.

Anthropometry↗
PubMed1999

Prenatal diagnosis of beta-thalassaemia by reverse dot-blot hybridization.

Thalassaemia is the most common genetic disease and is a public health problem of Thailand. Prevention and control of beta-thalassaemia diseases need accurate diagnosis of carriers and proper genetic counselling. Prenatal diagnosis is needed to prevent birth of the thalassaemic offspring in the couple at risk. This can be performed in the first trimester of pregnancy by DNA analysis using the polymerase chain reaction (PCR). Since there are more than 20 mutations causing beta-thalassaemia in Thailand, the point mutation detection by reverse dot-blot allele-specific oligonucleotide (ASO) hybridization was developed using two sets of ASO probes. The first battery of ASO probes has been designed to detect 10 common beta-globin gene mutations including codon 26, G->A (Hb E): codons 41/42, -TCTT; codon 17, A->T; IVS 2 nt 654, C->T; IVS 1 nt 1, G->T; IVS 1 nt 5. G->C; codon 19, A->G (Hb Malay); codon 35, C->A; codons 71/72, +A and -28 ATA, A->G. The second set of ASO probes detect 14 uncommon beta-thalassaemia mutations. We applied this reverse dot-blot hybridization technique to perform prenatal diagnosis in 105 pregnancies at risk of having severe beta-thalassaemia diseases. 36 fetuses (34 per cent) were found to be affected with homozygous beta-thalassaemia or beta-thalassaemia/Hb E disease in which one was twin pregnancy. The others included 31 fetuses with heterozygous beta-thalassaemia, 22 heterozygous Hb E, 1 homozygous Hb E and 16 normal fetuses. The common set of ASO probes detected about 95 per cent of cases which suggests that prenatal diagnosis for beta-thalassaemia disease can be easily carried out by this approach.

DNA Primers↗
PubMed1998

Prenatal and postnatal diagnoses of thalassemias and hemoglobinopathies by HPLC.

The conventional approach to qualitative and quantitative analyses of hemoglobin (Hb) molecules for the diagnoses of hemoglobinopathies requires a combination of tests. We used an automated HPLC (VARIANT) system to study alpha-thalassemia and beta-thalassemia syndromes in Thailand. The beta-thalassemia short program is applicable to the diagnosis of alpha-thalassemia and beta-thalassemia disorders, including Hb H, EA Bart's disease, and EF Bart's disease, in adults, newborns, and fetuses. The system cannot quantify accurately certain Hb molecules, such as Hb H and Hb Bart's. The alpha-thalassemia short program was therefore developed and used to quantify Hb Bart's to detect alpha-thalassemia genotypes in cord blood. This automated HPLC system is an alternative approach to the diagnosis of complicated thalassemia syndromes in Thailand and Southeast Asia.

Adult↗
PubMed1995

Detection of alpha-thalassemia-1 (Southeast Asian type) and its application for prenatal diagnosis.

A simple non-radioactive method based on the polymerase chain reaction was used to detect the Southeast Asian type of alpha-thalassemia 1 (--). Three oligonucleotide primers, one of which was adjacent to the breakpoint of the alpha-thalassemia-1 allele, were used to amplify the 570 and 194 bp DNA fragments. The 570 bp product was specific to the alpha-thalassemia-1 determinant and the 194 bp fragment was amplified from either the alpha-thalassemia-2 (-alpha) or normal alpha-globin (alpha alpha) determinants. In Hb Bart's hydrops fetalis (--/--), only the 570 bp fragment was obtained, whereas the 194 bp fragment was amplified in normal individual (alpha alpha/alpha alpha) and alpha-thalassemia-2 trait (-alpha/alpha alpha). Both 570 and 194 bp fragments were detected in alpha-thalassemia-1 trait (--/alpha alpha) and Hb H patients (--/-alpha). This procedure is useful for the rapid screening of alpha-thalassemia-1 trait and prenatal diagnosis of Hb Bart's hydrops fetalis in populations with a high frequency of the Southeast Asian Type of alpha-thalassemia-1.

Asia, Southeastern↗
PubMed1995

Prenatal diagnosis for beta-thalassemia syndromes using HRP-labeled oligonucleotide probes at Siriraj Hospital.

Characterization of the molecular defect of beta-thalassemia in Thais has enabled us to establish prenatal diagnosis for homozygous beta-thalassemia and beta-thalassemia/Hb E. The nature of the beta-thalassemia mutation of each high risk couple or of the previous affected child was firstly identified after counseling. Detection of beta-thalassemia mutations was performed by dot-blot hybridization of the amplified DNA with a set of HRP-labeled ASO-probes specific for the common mutations. If the mutation could be characterized, prenatal diagnosis (PND) would be performed by using DNA extracted either from the chorionic villi (CVS) or amniotic fluid fibroblast in the first trimester of pregnancy or from fetal blood in the second trimester. DNA analysis was carried out in 23 couples at risk of having homozygous beta-thalassemia and 88 couples at risk for beta-thalassemia/Hb E. However, PND was performed by this technique in 22 pregnancies from 21 couples at risk of having homozygous beta-thalassemia children and 86 pregnancies from 71 couples at risk for beta-thalassemia/Hb E; 9 couples underwent more than one prenatal diagnosis. The results showed that, although there are more than 20 beta-thalassemia mutations in the Thai population, PND by DNA analysis could be carried out in more than 95% of the risk couples by using beta(E) and 10 different HRP-labeled ASO probes. This technique was simple, economic and avoided the use of radioactive isotope.

Amniocentesis↗
PubMed1991

Prenatal diagnosis of thalassemia and hemoglobinopathies in Thailand: experience from 100 pregnancies.

In this review, we describe a simple strategy to detect the three severe thalassemic diseases commonly found in Thailand. Hb Bart's hydrops fetalis can be detected unambiguously by ultrasonography at 18-20 weeks of gestation or detected early in the first trimester by the gene amplification technique. Prenatal diagnosis for homozygous beta-thalassemia is better performed in the second trimester by in vitro protein synthesis. This is because the molecular defects of some beta-thalassemias are still unknown and homozygosity of the same mutation is low. In contrast, beta-thalassemia/Hb E is easily detected, in the first trimester, by direct visualization on electrophoresis or by dot blot analysis of enzymatically amplified DNA with a set of nonradioactively labeled oligonucleotide probes complementary to the most common mutations. We also found that the beta/gamma synthesis ratio in homozygous Hb E is similar to that of beta-thalassemia/Hb E and DNA analysis is the only method to distinguish these two conditions in the couple at risk of having either beta-thalassemia/Hb E or asymptomatic homozygous Hb E. In 100 pregnancies studied, the diagnoses were achieved in 96 pregnancies. Complications leading to fetal loss were found in 3 pregnancies: one woman developed amnionitis after fetal blood sampling; one had amniotic fluid leakage after the biopsy, and the third, carrying a normal fetus, aborted 10 days after fetal blood sampling with urinary tract infection and high fever. However, these figures are compatible with other reports and the risks are significantly lower than that of thalassemic disease the fetus is facing. One case of beta-thalassemia/Hb E was incorrectly diagnosed prenatally as being Hb E trait. In twenty-five pregnancies (25%) prenatally diagnosed to carry affected fetuses it was decided to have abortion. This study shows the feasibility of prenatal diagnosis for thalassemic diseases in Thailand which, in addition to screening and genetic counseling, can support prevention and control programs for thalassemia.

Female↗
PubMed1989

Percutaneous umbilical cord blood sampling.

Percutaneous umbilical cord blood sampling is a newer, safer, and more convenient technique and can be performed in the second and third trimester of pregnancy by direct puncture of the umbilical vein near its placental insertion, using a needle guided by ultrasound. Between 2-4 ml of pure fetal blood were obtained from 10 pregnancies at between 19 and 39 weeks' gestation. This new procedure offers access to the fetal circulation for diagnosis and therapeutic purposes.

Blood Specimen Collection↗