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T R Wang

Publications and source records attributed to T R Wang.

At least 37 records · Page 2Linked to original sources
PubMed1998

Human alpha-L-iduronidase (IDUA) gene: apparent recombination in intron 2 by haplotype analysis in a Taiwanese population.

The polymorphic DNA haplotype of the alpha-L-iduronidase (IDUA) gene in a Taiwanese population was investigated. Genomic DNA extracted from 85 volunteers was used to amplify fragments containing the polymorphic sites A8, A20 and Q33H from exon 1 and a variable number of tandem repeats (VNTR) region in intron 2. Additionally, sites R105Q and L118 in exon 3, A314 from exon 7, A361T and T388 from exon 8, T410 and V454I from exon 9, and R489 from exon 10 were amplified. The polymerase chain reaction-amplified products were analyzed by restriction fragment length polymorphism (RFLP) analysis, allele specific oligonucleotide (ASO) hybridization, or gel electrophoresis. Of the examined polymorphisms, the intron 2 VNTR was not in Hardy-Weinberg equilibrium. Conversely, all 11 single base change polymorphisms were in Handy-Weinberg equilibrium. Linkage disequilibrium analysis of the haplotype data revealed strong nonrandom association between A8 and A20 in exon 1 as well as among R105Q, A314, A361T, T388, T410, V454I, and R489 in exons 3 to 10. In contrast, little linkage disequilibrium between two clusters of linked polymorphisms on either side of the VNTR was observed. The results suggest apparent recombination in intron 2 of the IDUA gene, with little or no recombination in exon 1 or exons 3 to 10.

Adult↗
PubMed1997

Angelman syndrome assessed by neurological and molecular cytogenetic investigations.

Angelman syndrome (AS) is characterized by severe psychomotor retardation, speech impairment, happy disposition with bursts of laughter, ataxia, convulsions, and some distinct physical anomalies. Correct diagnosis of AS is important because of its clinical implications, and once the disease is confirmed, familial genetic counseling becomes crucial. We evaluated 22 patients with a putative diagnosis of AS by both clinical and molecular cytogenetic analysis. A deletion of the region 15q11-13 could be identified cytogenetically in 11 cases by high-resolution technique (group I). Four additional cases were confirmed by fluorescence in situ hybridization (FISH) study with D15S11, SNRPN, D15S10, and GABRB 3 [Prader-Willi syndrome (PWS)/AS region probes] (group II). The common deletion of GABRB 3 was documented in those AS cases (n = 15) by FISH. The other 7 cases exhibited no deletion over 15q11-13 at either the cytogenetic or molecular level (group III). We compared the following associated neurological disorders: convulsions and abnormal EEG, microcephaly, sleep and behavior problems, brain anomalies proved by image studies, sexual precocity with pineal tumor among the three groups, as well as other clinical conditions including congenital heart disease, obesity, scoliosis, and hypopigmentation. In the present study, the differences in neurological and facial characteristics were not distinct among these groups. However, the associated conditions were more frequently observed in the patients with deletion than in those without deletion. The EEG features of AS appear to be less sufficient in helping identify patients at an early age before the clinical features become obvious. Therefore, a region involved in the major As phenotypes may contain only one or more tightly contiguous genes around the GABRB 3 locus, which may explain the clinical heterogeneity in AS.

Adolescent↗
PubMed1997

Duplication of proteolipid protein gene: a possible major cause of Pelizaeus-Merzbacher disease.

The classic form of Pelizaeus-Merzbacher disease is a rare X-linked dysmyelinating disorder of the central nervous system in which mutations of the proteolipid protein gene have been reported since 1989. However, mutations in the proteolipid protein gene have been identified in only 10 to 25% of all cases of Pelizaeus-Merzbacher disease, which suggests that other genetic aberrations may be present. Recently, proteolipid protein gene overdosage was discovered to cause Pelizaeus-Merzbacher disease. By using comparative multiplex polymerase chain reaction and restriction fragment length polymorphism analysis, we confirmed the proteolipid protein gene duplication as the cause of Pelizaeus-Merzbacher disease in 4 patients from 3 Chinese families with Pelizaeus-Merzbacher disease with no detectable exonic mutations. These results support the hypothesis that proteolipid protein gene duplication may be a major cause of Pelizaeus-Merzbacher disease in all ethnic groups and also suggest that the molecular diagnosis of Pelizaeus-Merzbacher disease should therefore include duplication analysis of proteolipid protein gene.

Diffuse Cerebral Sclerosis of Schilder↗
PubMed1997

FMR1 enhancer is regulated by cAMP through a cAMP-responsive element.

FMR1 (Fra X Mental Retardation 1), a gene of unknown function, is responsible for an important hereditary mental retardation, the fragile X syndrome. In this study, a 22-bp enhancer (methylation sensitive element, MSE) in the FMR1 promoter was defined by DNase I footprinting assay, and the binding of this element by nuclear factor was prevented by DNA CpG methylation. A cAMP-responsive element (CRE)-like sequence and a myc-binding sequence in MSE were identified. In the transfection assay, MSE demonstrated a strong, methylation-sensitive enhancer activity. MSE could be bound by recombinant CRE-binding protein (CREB), and its activity was stimulated by CREB in a co-transfection assay. In PC12 cells, forskolin elevated MSE activity several fold, and this induction was abolished in CRE mutants. The involvement of cAMP in the expression of FMR1 should be a clue to both the function of FMR1 and the pathogenesis of fragile X syndrome.

Colforsin↗
PubMed1997

Characterization of hemin binding activity of Streptococcus pneumoniae.

Streptococcus pneumoniae is a causative agent of bacterial pneumonia, otitis media, meningitis, and bacteremia. It causes considerable morbidity and mortality throughout the world, especially among children, the elderly, and immunocompromised individuals. We have demonstrated previously that the growth of S. pneumoniae is limited under iron-depleted conditions and can be restored by the addition of either hemin or hemoglobin. In the present study, we showed that S. pneumoniae had the ability to bind hemin and that the level of hemin binding activity was not affected by supplementation of the growth medium with iron. Approximately 70 to 80% of the hemin binding activity was mediated by proteinase-resistant components, and the remainder was mediated by proteins. Hemin binding proteins were located in both soluble extract and envelope fractions of pneumococcal cells. By batch affinity chromatography, a major hemin binding polypeptide with an apparent molecular mass of 43 kDa was identified in the cell lysate of S. pneumoniae. Polyclonal antibodies against this polypeptide were raised. By immunoblot analysis, this hemin binding polypeptide was localized in the envelope and did not exhibit any variation in molecular weight among all serotypes tested. The subcellular distribution of hemin binding activity may have functional implications.

Carrier Proteins↗
PubMed1997

Mucopolysaccharidosis type I: identification of novel mutations that cause Hurler/Scheie syndrome in Chinese families.

The complementary and genomic DNA segments of the alpha-L-iduronidase gene from two Chinese mucopolysaccharidosis type I Hurler/Scheie (MPS IH/S) patients were amplified by polymerase chain reaction (PCR) and DNA sequencing was done to study their molecular lesions. Patient W3 has heterozygous mutations; the maternal allele has M1I (G to A transition in the initiation codon ATG) and the paternal allele has Y343X (C to G transversion in exon 8 leading to in frame deletion of codons 325-343 from the mRNA owing to false splicing). Patient W2 is homozygous for mutation T364M (C to T transition in codon 364). The mutation was paternally inherited. A de novo deletion or gene conversion event may have resulted in apparent homozygosity for T364M. Expression of Y343X and T364M showed trace amounts of alpha-L-iduronidase activity compared to that of normal cDNA upon transfection into COS-7 cells.

Animals↗
PubMed1997

Immunologic epitope, gene, and immunity involved in pneumococcal glycoconjugate.

Pneumococcal infection persists as a major cause of pneumonia, otitis media, and meningitis in infants. Children less than 2 years of age show the highest incidence of pneumococcal diseases. Production of monoclonal antibody (MAb) to polysaccharide (PS) and binding characteristics to PS epitopes were studied. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in a decreased binding with rabbit 9V antiserum (AS). However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. Type 9V IgG MAb provided passive protection and enhanced the opsonophagocytic activity of polymorphonuclear (PMN) leukocytes to kill type 9V pneumococci. The pathogenecity of pneumococci is attributed to various virulence factors distributed on the cell surface, including capsular polysaccharide and protein antigens, for example, pneumolysin, autolysin, pneumococcal surface protein A (PspA), pneumococcal surface adhesion (PsaA), and hemin binding protein. Some of these protein antigens may be used as a component to combine with pneumococcal PS vaccine or as a carrier of conjugate vaccine. Clinical trials of pneumococcal conjugate vaccines showed that covalent linkage of capsular PS to protein carriers improved the immunogenicity of the PS. Development of glycoconjugate vaccine for selected pneumococcal types will help solve the problem of poor immunogenecity of PS vaccine in young children used for prevention of pneumococcal infection.

Amino Acid Sequence↗
PubMed1997

Ornithine transcarbamylase deficiency.

Two infants, one male and one female, with elevated serum ammonia levels, were shown, based on urine organic acid analysis and DNA studies, to have ornithine transcarbamylase (OTC) deficiency. OTC deficiency is one of the most common urea cycle disorders. Hyperammonemia occurred at 3 days of age in the male infant, and at approximately 7 days of age in the female infant. Administration of sodium benzoate and sodium phenylacetate lowered the serum ammonia level effectively in both cases. Other modalities, including peritoneal dialysis and protein restriction, were also important in the control of the serum ammonia level. The mother of the male infant was shown to be a carrier of the OTC gene mutation by allopurinol loading test. The mutation site of the OTC gene for the female infant was identified, but her mother did not have the mutation. OTC deficiency, an incompletely dominant X-linked disorder, is a severe disease even for females and prompt treatment and precise genetic counseling are mandatory.

Female↗
PubMed1997

Primed in situ (PRINS) labeling for rapid detection of numeric and structural chromosome anomalies.

Primed in situ (PRINS) labeling has been applied to replace the traditional fluorescence in situ hybridization (FISH) method for the detection of specific sequences in situ in several numerical and structural chromosome anomalies. PRINS is based on sequence-specific annealing in situ of an unlabeled DNA probe or oligonucleotide primer. The probe serves as a primer for chain elongation in situ, using the labeled nucleotides as substrate. An oligonucleotide, (CCCTAA) representing human telomeric sequences, was mixed with nucleotides, biotin-16-dUTP, and Taq DNA polymerase, and applied on metaphase slides with ring chromosomes 4, 13, 18, X and Y. Primers for alpha-satellite sequences specific for the centromeric regions of human chromosomes 13, 15, 18, X and Y were also used to characterize the nature and origin of unidentifiable supernumerary marker chromosomes. The specificity of PRINS in differentiating centromeric sequences of chromosome [3 from 21 which is not possible with FISH, was demonstrated. Absence of the telomeric sequences in all of the ring chromosomes was noted in normal and abnormal phenotypes. The results suggest a mechanism of ring formation, an end-to-end fusion after loss of the palindromic nucleotide sequences at the telomeres PRINS, a fast and sensitive method of detecting nucleic acid sequences in situ, may be a reliable technique for detecting chromosomal aneuploidies and some structural rearrangements.

Chromosome Aberrations↗
PubMed1997

Microdeletion oe chromosomal region 7Q11.23 in Williams syndrome.

We report two children with typical Williams syndrome facial appearance, growth deficiency and developmental delay. Both had supravalvular aortic stenosis (SVAS) and peripheral pulmonary stenosis (PPS), but no hypercalcemia. Chromosomal study in the first case, a 40-day-old girl, revealed a cytogenetically visible proximal interstitial deletion of the 7q11.22-11.23 segment. Another patient, a 3-year-old boy, with a normal karyotype, had milder phenotype with spontaneous remission of SVAS and PPS. Both patients showed allelic loss of the elastin (ELN) gene, exhibiting a submicroscopic deletion at 7q11.23, which was detected by fluorescence in situ hybridization (FISH). The results support the usefulness of FISH for detection of ELN gene deletion as an initial diagnostic assay for patients with SVAS or Williams syndrome. To our knowledge, these are the first cases of Williams syndrome in Taiwanese patients to be proven clinically, cytogenetically and by molecular analysis.

Chromosome Deletion↗
PubMed1997

Tricho-rhino-phalangeal syndrome type II associated with epiglottic aplasia and congenital nephrotic syndrome.

A male neonate with tricho-rhino-phalangeal syndrome type II (Langer-Giedion syndrome) and interstitial deletion of chromosome 8 with karyotype 46, XY, del (8) (q24.11-->q24.13) is reported. In addition to hypotrichosis of the scalp hair, abnormally bulbous nose and redundant skin, which are usually found in this syndrome, aplasia of the epiglottis and non-Finnish type congenital nephrotic syndrome were also present. He died of renal failure and respiratory failure at 11 days of age. Electron microscopy of renal necropsy showed foot process loss, focal thickening and splitting of the glomerular basement membrane and mesangial expansion. These have never been reported and could be new associations in this disease that may serve to support the concept of contiguous gene syndrome in patients with tricho-rhino-phalangeal syndrome.

Epiglottis↗
PubMed1997

CATCH 22: deletion of locus 22q11 in velocardiofacial syndrome, DiGeorge anomaly, and nonsyndromic conotruncal defects.

DiGeorge anomaly (DGA) and velocardiofacial syndrome (VCFS) are frequently associated with monosomy of chromosomal subband 22q11. It is not clear whether individuals who present with only some of the features (e.g., isolated hypoparathyroidism or conotruncal defects) of these conditions also have the same deletion. In a prospective study of 30 children from 1994 to 1996, we used both high-resolution banding and fluorescence in situ hybridization (FISH) to assess the deletion status of children with a wide range of DGA-like or VCFS-like clinical features. Microdeletion of the chromosomal subband 22q11.22 was detected in 17 children by high-resolution banding and in two additional children with conotruncal defect (CTD) who had submicroscopic deletions proved by FISH analyses. Of the patients with microscopical deletion (n = 17), only six had classical DGA (n = 4) or VCFS (n = 2) phenotypes. The other 11 had various forms of congenital heart defects as the only presenting signs of deletion. One patient with DGA stigmata had another chromosomal aberration of monosomy 10p13. Only 10 patients were found to have neither cytogenetic nor molecular abnormalities. Therefore, it appeared that the majority, if not all, of the DGA and VCFS patients with the 22q11 deletion were identifiable using FISH with the single N25 (D22S75) probe. It would also be advisable that children with isolated CTD should be carefully examined to detect the other morphologic abnormalities of DGA and VCFS, or CATCH 22 (cardiac defects, abnormal facies, thymic hypoplasia/aplasia, cleft palate, hypocalcemia, and 22q11 deletion). Once these abnormalities are found, a molecular cytogenetic analysis for the so-called 22q11 region is indicated. Because of other associated chromosomal findings, routine or high-resolution cytogenetic analysis should be performed on patients with suspected CATCH 22.

Abnormalities, Multiple↗
PubMed1997

Partial DiGeorge anomaly associated with 10p deletion.

We report a girl with partial DiGeorge anomaly associated with a distal chromosome 10p deletion. The initial manifestation was hypocalcemia convulsion at the age of 14 days. The patient was small for her gestational age and showed symptoms of poor feeding and inspiratory stridor. Facial dysmorphisms included a cupped ear, hypertelorism downslanted and short palpebral fissures frontal bossing, anteverted nostrils, a flat nasal bridge, and micrognathia. Developmental delay was also noted. Hypoplasia of the thymus was detected by ultrasound examination, but results of immunologic studies were all normal at 6 weeks of age. The echocardiogram, brain ultrasound, electroencephalogram, and magnetic resonance images of the brain were normal, but brainstem auditory evoked potentials showed bilateral sensorineural hearing loss. Chromosomal analysis showed 16, XX, del(10)(p12.3); the parents had normal karyotypes. After treatment with vitamin D, calcium gluconate, and magnesium sulfate, the patient's serum calcium and magnesium levels were within normal limits. She was discharged and received regular follow-up at our clinic for physical therapy and to ensure adequate supply of divalent cations. Complex partial seizure was noted at the age of 1 year and was controlled with carbamazepine. To our knowledge, this is the first Taiwanese reported to have partial DiGeorge anomaly associated with 10p deletion. We recommend that standard karyotyping should be performed in children suspected to have this anomaly.

Chromosome Deletion↗
PubMed1996

Arylsulfatase A pseudodeficiency in Chinese.

Arylsulfatase A (ASA) pseudodeficiency was found to be much rarer in Taiwan than in most western countries (2.5% versus 7.3%-20% carrier rate). The linkage of two mutations (A2725G and A1788G) in the pseudodeficiency allele was preserved in Chinese, and A2725G did not occur alone. This unusual linkage of mutations has not been fully explained previously because the frequency of A2725G alone was not clear (as low as 4% in the only report). However, A1788G was found in 55 of 160 (34.4%) DNA samples tested in this study. These data suggest that the A2725G mutation occurred in DNA that already contained the A1788G change, at an ancient time in one of our common ancestors.

Asian People↗
PubMed1996

Homocystinuria presenting as fatal common carotid artery occlusion.

A patient with homocystinuria presenting with fatal cerebral infarction that resulted from left common carotid artery occlusion is reported. This 13-year-old, healthy and intelligent girl presented with progressive cerebral infarction. Angiography revealed total occlusion of the left common carotid artery and stenosis of the right common carotid artery. Distal stenosis of bilateral vertebral arteries was also observed. Initially Takayasu arteritis with unusual manifestation was considered. However, later investigations revealed homocystinuria was the underlying cause. The sudden onset of fatal stroke as the initial clinical presentation of homocystinuria, as observed in this previous healthy teenager, is noteworthy. We suggest metabolic screening for homocystinuria when treating a patient with unusual vascular lesions.

Adolescent↗
PubMed1996

Production, binding characteristics and protective immunity of monoclonal antibody to pneumococcal type-9V conjugate.

A monoclonal antibody (MAb) to pneumococcal type-9V polysaccharide (PS) was produced using PS conjugated to inactivated pneumolysin as the immunogen. The MAb to 9V PS was of the IgG1 subclass. The antigen-antibody reaction increased rapidly at low concentrations and reached a plateau at 10 micrograms PS/ml as measured by nephelometry of the group 9 PS against 9V MAb binding. In contrast, the binding of group 9 PS against rabbit 9V antiserum (AS) increased proportionally and continued to increase up to the highest concentration of PS tested (20 micrograms PS/ml). The 9V MAb reacted with all group 9 PSs (9A, 9L, 9N and 9V) by immunodiffusion. In the homologous 9V Ag-MAb reaction, there were marked differences in the inhibition of binding by the cross-reactive 9L PS (19.2% inhibition) and the 9N PS (0.2%). In contrast, inhibition of the homologous 9V Ag-rabbit AS binding by cross-reactive 9L and 9N PSs ranged from 57.8 to 62.7%. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in decreased binding with rabbit 9V AS. However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. The 9V MAb was both opsonic and passively protected young mice against challenge with type-9V pneumococci.

Animals↗