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Biomedical subjects

T R Wang

Publications and source records attributed to T R Wang.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Trisomy 18 in a patient with CHARGE association.

CHARGE association is the non-random association of congenital anomalies, including colobomata of the eyes, heart defects, choanal atresia, retardation of growth and development, genital hypoplasia and ear abnormalities. It is usually a sporadic event of unknown cause. We report a neonate with trisomy 18 and apparent CHARGE association. The associated abnormalities made the diagnosis difficult until the chromosomal results became available. Abnormalities such as clenched hands and short palpebral fissures pointed to the possibility of a chromosomal anomaly. The chromosome study revealed trisomy 18. It is important to perform chromosomal studies quickly when diagnosing a patient with apparent CHARGE association who also has other minor anomalies atypical of CHARGE.

Abnormalities, Multiple↗
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Sex determination in infants with ambiguous genitalia using the polymerase chain reaction of SRY gene.

It has long been known that testes arise only in the presence of a Y chromosome. The existence of a hypothetical gene, the testis-determining factor (TDF) on the Y chromosome, has therefore been postulated. SRY is the gene located in the sex-determining region of the human Y chromosome and has many of the properties expected for TDF. To evaluate the value of SRY PCR in sex determination, individuals with ambiguous genitalia were selected for study. By identification of the DNA sequence of SRY, a 609-bp fragment of PCR product, sex determination could be successfully made.

Base Sequence↗
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Transient tyrosinemia presenting as lactic acidosis in a term baby: report of one case.

Tyrosinemia is one of the disorders of aromatic amino acid metabolism. The report describes a male newborn who presented with tachypnea, lethargy, diarrhea and metabolic acidosis at 12 days old, with an elevated level of lactic acid. Tyrosinemia was impressed according to elevated plasma tyrosine level and specific metabolites of tyrosine detected by gas chromatography/mass spectrometry (GC/MS) study. The symptoms/signs subsided within one month after supportive treatment and protein restriction. Transient tyrosinemia of the newborn is indicative of delayed maturation of the liver enzyme systems (i.e. p-hydroxyphenylpyruvate dioxygenase), and is not a true inborn error of metabolism. Lactic acidosis is a rare associated findings in this condition.

Acidosis, Lactic↗
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Cytogenetic investigations in trisomy 21 with reciprocal 4/9 translocation: report of a case.

A 3-month-old male infant with Down's syndrome resulting from de novo trisomy 21 had an additional reciprocal translocation between the long arms of chromosomes 4 and 9: 47,XY,+21,rcp t(4;9)(q35;q22.3). Both C- and Ag-NOR bandings showed that the extra chromosome 21 was maternal in origin, but that the translocated chromosome 9 was from the father. To evaluate the nature of the translocation, fluorescence in situ hybridization (FISH) with whole chromosome painting probes (Coatasomes 4 & 9), followed by an enzymatic precipitation (HRP-DAB) assay was used. Whole chromosome FISH demonstrated the origin of the translocated region and clarified the karyotype. Enzymatic methods achieved the same result and were kept as a permanent record.

Chromosomes, Human, Pair 4↗
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Diagnosis of I-cell disease.

I-cell disease (mucolipidosis II) is a rare lysosomal storage disease, with its primary defect the deficiency of an enzyme responsible for lysosomal enzyme processing, resulting in multiple lysosomal enzyme insufficiency. Diagnosis of I-cell disease usually can be made by the specific patterns of enzyme distribution: deficient intracellular, but excessive extracellular, enzymes. A six month old female infant was found to have bilateral congenital dislocation of hips, developmental delay, coarsening of facial appearance and dysostosis multiplex. In view of the very early onset of disease, I-cell disease was suspected. Lysosomal enzyme tests (including alpha-mannosidase, alpha-fucosidase, beta-glucuronidase and beta-galactosidase) were performed on the leukocytes, skin fibroblasts, plasma and media from fibroblast cultures. All activities of the four enzymes were low in both leukocytes and fibroblasts, but were 10- to 70-fold higher than normal in plasma, and high in culture media. Both the clinical and laboratory findings here were consistent with a diagnosis of I-cell disease.

Clinical Enzyme Tests↗
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Beemer-Langer type short rib-polydactyly syndrome: report of two cases.

Two sibs who died shortly after birth had multiple congenital anomalies that included hydrops, narrow thorax, short limbs, and absence of polydactyly; therefore short rib (polydactyly) syndrome Beemer-Langer type was suggested. We report these cases and discuss the differentiation with Majewski type.

Abnormalities, Multiple↗
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Tuberous sclerosis in children.

Tuberous sclerosis (TS) is a multiple-system disease involving the brain, skin, kidneys, heart and other visceral organs. There were 18 children with TS at our clinic, and complete studies of these patients and their families were performed. Male to female ratio was 11:7. Age at diagnosis was from 1 month to 18 years. Seizures (infantile spasm, generalized and partial epilepsy), skin lesions and intracranial calcifications were the most common clinical manifestations. Mental retardation was closely correlated with seizure attacks. Neoplasms of the brain, retina, heart, lung and kidneys were all encountered. Hypopigmented macules, intracardiac tumors and infantile spasms were usually the first signs in younger ages and can give hints of early diagnosis of TS. In total, six patients had positive family histories and one of them had non-penetrating parents. Detailed family studies are mandatory prior to genetic counseling.

Adolescent↗
PubMedDate not supplied

Fragile-X mental retardation--a combination of cytogenetic and molecular approaches, with greater emphasis on DNA analysis.

Fragile X syndrome is one of the most frequent causes of hereditary mental retardation. In the past, its diagnosis depended primarily on cytogenetic demonstration of chromosome fragile site Xq27.3. Recently, the gene FMR-1 has been found responsible for this disease. Here a combined method was used to study fragile X syndrome. A fragment (pP1fr) of DNA was subcloned from pE5.1 by polymerase chain reaction. With this probe, DNA samples from two cytogenetically proved families were analyzed by restriction fragment length polymorphisms. It was demonstrated that EcoRI polymorphism was an easy and accurate method for diagnosis of the fragile X syndrome. To study methylation status of patients, another methylation-sensitive enzyme, BssHII, could be used together with EcoRI. The PstI polymorphism of one family was also studied and showed one kb fragment as normal, and detected more precise changes in length. Prominent mosaicism necessary was characteristic in PstI polymorphism. The DNA diagnosis of fragile X syndrome was a reliable method.

Base Sequence↗
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Y-specific polymerase chain reaction for the interpretation of a chromosome marker.

Chromosome marker is a very special type of chromosomal aberration. In addition to their normal chromosomes, patients with this type of disease own one (or more) small, unrecognizable chromosome. The extra chromosome markers may originate from the products of breakage and translocation of other chromosomes. Interpretation of the chromosome marker is usually very difficult, but its presence is an important prognosis factor for patients if the marker originated from a Y chromosome, or its components. This study explores the possibility of interpreting the chromosome marker by Y-specific polymerase chain reaction. A pair of primers designed from one Y-specific DNA sequence was employed. By studying normal controls, the most specific conditions for the chain reaction were established. Comparison of normal males and females showed that this reaction is specific to males (that is, to the Y chromosome). Also one patient with a karyotype 46,X,+marker was studied. The external genitalia of this patient were female type except for an enlarged clitoris. Y-specific polymerase chain reaction showed that the patient did have the Y-specific sequence. The chromosome marker did originate from the Y chromosome. This work proposes that Y-specific polymerase chain reaction is an effective and necessary diagnostic procedure for patients with chromosome marker.

Base Sequence↗
PubMedDate not supplied

Molecular diagnosis of Gaucher disease type II.

Gaucher disease is a rare autosomal recessive lysosomal storage disorder in Chinese. A mutation at nucleotide 1448C (T-to-C) of the glucocerebrosidase gene is described in type 2 Gaucher disease. This mutation creates a Bcn I site in a polymerase chain reaction (PCR) amplified fragment. This technique was applied to a Chinese infant with type 2 Gaucher disease, and homozygosity for 1448C mutation was proved. This new finding can make prenatal diagnosis and carrier detection possible in Chinese population with type 2 Gaucher disease.

Base Sequence↗
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Bony changes in common mucopolysaccharidoses.

To evaluate the radiological features of mucopolysaccharidoses (MPS), 15 cases were collected for review in this hospital, retrospectively (1985-1995). Eight cases of Hurler syndrome, two cases of Hunter syndrome, two cases of Sanfilippo syndrome and three cases of Morquio syndrome were classified. Varying severity of dysostosis multiplex is the general bony manifestation of MPS, but special appearance may occur in particular types. Hurler syndrome is the prototype of MPS. The main findings were as follows: "J" shaped sella turcica, paddle-like ribs, anterior inferior beaking (hook-like) of lower thoracic-upper lumbar hypoplastic vertebral bodies, flared iliac wings, constrictive iliac bodies, diaphyseal expansion of long bones, distal ulna and radius tilt toward each other, bullet-like proximal phalanges and central pointing of proximal metacarpals. Hunter and Sanfilippo syndromes had the appearance of moderate to mild dysostosis multiplex. Morquio syndrome had distinctive bony changes as vertebral plana and tongue-like protrusion in the anterior part of the lower thoracic-upper lumbar vertebral bodies, particularly short of the distal deformed ulna and poor ossification of the proximal lateral tibial epiphyses. Although clinical presentations and the hallmarks of bony changes helped possible classification of MPS, definite diagnosis depends on enzyme analysis.

Bone and Bones↗
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Sex determination in infants with ambiguous genitalia using the polymerase chain reaction of an X-Y homologous region.

A polymerase chain reaction (PCR) technique applicable for sex identification is described. The technique amplifies a part of the X-Y homologous amelogenin gene in which the Y counterpart has a 189 bp deletion within one of the introns. To evaluate the value of PCR of a X-Y homologous region in sex determination, individuals with ambiguous genitalia were selected for study. By identification of the X and Y sequences based on the difference in their sizes, sex determination could be successfully made.

Base Sequence↗
PubMedDate not supplied

Oculomotor apraxia in a case of Gaucher's disease with homozygous T1448C mutation.

We report a 10-month-old male infant with Type 2 Gaucher's disease. In addition to gradual arrest of neurological development, laryngospasm, opisthotonus, and limb rigidity, he presented characteristic oculomotor apraxia. History taking revealed that he had had abnormal horizontal gaze and had to turn his head to follow an object instead of moving the eyes alone. His eyes were in a divergent position while he was in a deep coma; however, when consciousness improved, he could open eyes with neutral eye position. Due to the impairment of reflex saccades, the doll's eye phenomenon was not reliable in evaluating the brainstem function when he was in the comatose stage. His leukocyte glucocerebrosidase activity was very low, but the typical Gaucher cell was absent in the sample of bone marrow aspiration. Molecular analysis by amplification refractory mutation system (ARMS) screening proved that he was a homozygote for T1448C mutation. To our knowledge, the T1448C gene frequency of Chinese Gaucher's disease is high. Thus, the ARMS screening method is applicable for further genetic diagnosis of Chinese Gaucher patients. Finally, this successful genetic diagnosis makes it possible in the future to perform prenatal diagnosis.

Apraxias↗
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Diagnosis of mucopolysaccharidosis type IIIB.

Mucopolysaccharidosis (MPS) includes a group of lysosomal storage diseases. Among them, type III (Sanfilippo) disease is rarely described in Taiwan because of their complexity. With accurate quantifying and precise separation of urinary glycosaminoglycans (GAGs), and specific enzyme measurements, two cases of MPS IIIB disease were able to be described. They both had mild-to-moderate degrees of mental retardation, facial dysmorphism and dysostosis multiplex which do not differ from other types of MPS. Total amounts of GAGs in the urine were only mildly elevated but, among them, heparan sulfate was the highest. Skin fibroblasts alpha-N-acetyl-glucosaminidase activities were low in both cases. Therefore, analysis of GAGs and enzyme assays are important for the diagnosis of patients suspected to have MPS, especially type III disease.

Acetylglucosaminidase↗
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Camptomelic dysplasia: report of one case.

A typical case of camptomelic dysplasia was noted to have only prenatally bowed legs. The infant showed the following characteristic features: dolichocephaly, flat-appearing small face, low nasal bridge, micrognathia, cleft palate, anterior bowing of tibia with skin dimpling over convex surface, mild bowing of femurs, talipes equinovarus, and tracheomalacia. Because of poor prognosis, the parents decided not to resuscitate the baby aggressively and the baby died of respiratory failure at six days old. Although this disease is rare, it does happen in ethnic Chinese and, because it may be an inherited disease, a correct diagnosis for camptomelic dysplasia is very important.

Abnormalities, Multiple↗
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Differentiation of Fanconi anemia from aplastic anemia by chromosomal breakage test.

Aplastic anemia (AA) is a disorder of heterogeneous pathogenesis caused by diverse etiologies. Fanconi anemia (FA) has the similar features of pancytopenia but is characterized by spontaneous or induced chromosomal instability and a variety of congenital anomalies. A cytogenetic breakage study is used to enable the diagnostic differentiation between FA and the so-called "idiopathic" AA. This method is based on the effect of the bifunctional alkylating agent mitomycin C (MMC) and alkylating mutagen diepoxybutane (DEB) on the chromosomes of peripheral lymphocytes in culture. Among thirty-three new cases of bone marrow failure with unknown etiologies, three young male patients were confirmed as victims of FA. The methodology and clinical manifestations were discussed. A prenatal screening was also performed to exclude the possibility of homozygous FA in one fetus at risk. The adequate dose of MMC used in our tests for diagnosis of FA were 20 ng/mL, while DEB did not work. These findings may suggest genetic diversity or other contributing factors in the pathogenesis of FA.

Anemia, Aplastic↗
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Congenital short bowel syndrome with left acheiria: report of one case.

A case of congenital short bowel syndrome with left acheiria, hemivertebra and dextrocardia is described. Dilatation of the fetal bowel was observed at the 24th week of gestation during a routine ultrasonic scan of a healthy 23-year-old primigravida from a non-consanguineous marriage. Amniocentesis and chorionic villus sampling were denied. The baby was delivered at 38 weeks of gestational age. After delivery, multiple anomalies were noted: left acheiria, congenital short bowel syndrome (15 cm in length of the ileum), pseudo-obstruction of intestine, dextrocardia, and hemivertebrae. We suspected these abnormalities might be due to a vascular accident or failure of lateralization during the early gestational period. To our knowledge, these combinations have not been reported previously in English literature.

Adult↗