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Biomedical subjects

P L Wilmot

Publications and source records attributed to P L Wilmot.

At least 19 recordsLinked to original sources
PubMed1994

Asymmetry of methylation with FMR-1 full mutation in two 45,X/46,XX mosaic females associated with normal intellect.

The full FMR-1 mutation is known to cause the fragile X syndrome [Fra(X)], but variable expression in females, including normal to deficient intellect, may be related to random X-inactivation (lyonization). We have evaluated 2 mosaic 45,X/46,XX females who are cytogenetically fra(X) positive, have an FMR-1 full mutation, and are of normal intellect. There were 50% fra(X) chromosomes in the 45,X cells of one of the females; this has not been reported previously. In both patients, there was a strong asymmetry of FMR-1 methylation with the normal allele being totally or 90% unmethylated and the mutant allele being similarly methylated. Thus, the apparent selective inactivation of the full mutant FMR-1 allele appears to have resulted in limited expression with normal intellect. The presence of the fra(X) chromosome in 45,X cells is unique; however, there may be no relationship to the asymmetric inactivation of the mutant allele which could be due to chance or a mechanism yet to be delineated.

Adolescent↗
PubMed1993

Multiple meningiomas in a patient with constitutional ring chromosome 22.

We report on a patient with multiple congenital anomalies and ring chromosome 22 who died at age 16 years of bronchopneumonia. Autopsy documented multiple psammomatous meningiomas of the spinal dura and tentorium. Tumor tissue for cytogenetic analysis was not available. Although abnormalities of chromosome 22 in tumor tissue have been reported, to our knowledge, this is only the third report of a constitutional chromosome 22 abnormality associated with the development of meningiomas. Thus, a constitutional chromosome 22 abnormality may predispose to the development of meningiomas.

Abnormalities, Multiple↗
PubMed1993

Kallmann syndrome associated with complex chromosome rearrangement.

We report on a male with Kallmann syndrome (KS) and an apparently balanced complex chromosome rearrangement (CCR): 46,XY,t(3; 9)(9;12)(q13.2;q21.2p13;q15). This is the first known report of a CCR in the KS and the second reported case of a definitive autosomal chromosome abnormality with KS. Possible relationships between the cytogenetic abnormality and KS are discussed.

Adult↗
PubMed1991

Prader-Willi syndrome and Robertsonian translocations involving chromosome 15.

A case of Prader-Willi syndrome is presented in which high resolution chromosome analysis revealed not only a familial Robertsonian translocation [t(13q15q)], but also a del(15) (q11.2q13) of the chromosome 15 not involved in the translocation. While there have been numerous reports of Robertsonian translocations involving chromosome 15 in patients with Prader-Willi syndrome, in this case, the Robertsonian translocation was shown to be unrelated to the clinical findings.

Adult↗
PubMed1991

Molecular markers of fragile X: clinical aspects of carrier detection and prenatal diagnosis.

In our families, a determination of carrier or affected status was made in more than 75% of cases using a standard panel of five marker systems: three proximal (F9, DXS105, DXS98) and two distal (F8, DXS52). Five additional systems, three proximal (DXS10, DXS51, DXS102) and two distal (DXS15, DXS33), were used in cases resistant to analysis with the standard panel. In 60% of cases, flanking markers were identified (proximal and distal). Utilizing the complete panel, only 5% of cases did not have any informative markers identified. In order to facilitate the appropriate application of molecular methods, several simple rules should be followed by the genetic service provider when dealing with fra(X) families: 1. Cytogenetic prescreening of females may be helpful. Only negative or ambiguous fra(X) expression levels justify the labor-intensive DNA-based family studies. 2. At present, DNA-based studies are the only way to ascertain male carrier status. 3. Every effort should be made to perform DNA-based studies under maternal phase-known conditions. 4. Information should be collected and pedigrees prepared for both sets of maternal grandparents. 5. Fathers of female consultands should be directly DNA-typed to rule out non-paternity. 6. Genetic counseling should be conservative, i.e. the "worst" scenario presented to these families, in order to avoid underestimating the risk of transmission to the next generation.

Cells, Cultured↗
PubMed1990

Deletion of 16q with prolonged survival and unusual radiographic manifestations.

Deletion of 16q is characterized by mental retardation, microcephaly, a characteristic combination of minor facial anomalies, and broad halluces. Various break points have been described. This patient's phenotype is typical of this syndrome, but in addition, unusual radiographic findings were present. This chromosome abnormality is compatible with survival into adulthood. Expression of this phenotype does not appear to be correlated with specific break points.

Abnormalities, Multiple↗
PubMed1990

Establishment of new human prostatic cancer cell line (JCA-1).

The establishment of a new human prostatic cancer cell line is described. This cell line was derived from a poorly to moderately differentiated prostatic adenocarcinoma. It has been maintained in tissue culture for fourteen months and has been passed fifty-two times. This cell line has an ability to form colonies in soft agar suspension cultures, and also is transplantable to nude mice. Tumors grown in nude mice revealed a poorly differentiated adenocarcinoma with positive PSA staining. Acid phosphatase activity was detected in freeze-thawed cells by enzymatic assay. A karyotype analysis demonstrated aneuploidy with a model chromosomal number of 69 and six marker chromosomes.

Acid Phosphatase↗
PubMed1990

Disomic balanced reciprocal translocation.

The previously unreported and unique finding of a complete disomy of an apparently balanced reciprocal translocation is described. The parents are second cousins once removed and each parent contributed the same balanced reciprocal translocation chromosome. Although the complete disomy involves balanced translocation chromosomes from unaffected parents, it is possible that a hemizygous state of some genes may be present on each translocation chromosome, which in a disomic homozygous state could result in an abnormal phenotype, as manifested by infantile seizures in this patient.

Chromosomes, Human, Pair 16↗
PubMed1989

Trisomy 5 mosaicism in amniotic fluid with normal outcome.

A case of prenatally diagnosed true mosaicism for trisomy 5 with a clinically normal outcome is presented. Trisomy 5 was detected in 23% of cells obtained by amniocentesis, but it was not detected from cells obtained by fetal blood sampling. While in this case the finding at amniocentesis did not reflect the status of the fetus, care must be exercised in reaching this conclusion in all cases.

Adult↗
PubMed1989

Philadelphia chromosome (Ph1)-positive acute lymphoblastic leukemia (ALL) is resistant to effective therapy for Ph1-negative ALL.

Amsacrine with high-dose cytarabine is effective therapy for Philadelphia chromosome (Ph1)-negative acute lymphoblastic leukemia (ALL). We examined the effectiveness of this regimen in 19 patients with Ph1-positive lymphoblastic leukemia. Four had an antecedent chronic phase of chronic myelogenous leukemia and 15 presented with ALL. There were no complete responders in either group. All 14 patients whose bone marrow could be assessed after completion of therapy showed persistent leukemia. We conclude that patients with Ph1-positive lymphoblastic leukemia have a disease that is resistant to treatment that is highly effective in patients with Ph1-negative ALL.

Adolescent↗
PubMed1988

The karyotype of Philadelphia chromosome-negative, bcr rearrangement-positive chronic myeloid leukemia.

Philadelphia (Ph) chromosome negative chronic myeloid leukemia (CML) can be distinguished from clinically similar disorders on the basis of the presence of rearrangement of the breakpoint cluster region (bcr) of chromosome 22. We have identified six patients with Ph-negative CML, each with bcr rearrangement. Apparently normal karyotypes were observed in two cases, and a third contained a rearrangement that did not appear to involve chromosomes 9 or 22. The other three cases had translocations involving chromosome band 9q34 but no case contained the common derivative chromosome 9pter----9q34::22q11----22qter. One case appeared to contain either a deletion of an unrearranged bcr locus in approximately 50% of cells or duplication of rearranged bcr, both 5' and 3' of the chromosome 22 breakpoint. Considerable complexity exists in the types of genetic changes that can juxtapose bcr and the c-abl oncogene in CML. Based on the molecular and cytogenetic analyses of these and other cases described in the literature, we conclude that most cases of true Ph-negative CML arise from submicroscopic genetic exchanges rather than masking of simple t(9;22)(q34;q11) translocations by secondary rearrangements.

Adult↗
PubMed1988

The use of early simultaneous percutaneous umbilical blood sampling (PUBS) and amniocentesis for prenatal fragile X chromosome diagnosis.

Early simultaneous percutaneous umbilical blood sampling (PUBS) and amniocentesis for prenatal diagnosis were undertaken for the first time in a 17-week gestation fetus at risk for the fragile X [fra (X)] syndrome. Metaphase spreads from 300 fetal lymphocytes were examined within 5 days following PUBS, while approximately 5 weeks were required for the analysis of 148 amniocytes. The chromosomes were interpreted as normal (46,XX) and the fetus as fragile X-negative at the time of prenatal diagnosis. This was cytogenetically confirmed after delivery of a healthy term female infant. Our results suggest that early PUBS may become a useful adjunct to amniocentesis because of shorter culture time and earlier diagnosis.

Amniocentesis↗
PubMed1979

Greig cephalopolysyndactyly syndrome.

Based on the family presented and five others previously described, it can be concluded that the Grieg cephalopolysyndactyly syndrome is a fully penetrant autosomal dominant disease consisting of four variably expressed malformations: postaxial polydactyly (type B), preaxial polydactyly, syndactyly, and minor craniofacial abnormalities. This entity can be differentiated from other craniofacial-digital syndromes because of the absence of mental retardation, craniosynostosis, and brachydactyly.

Adult↗
PubMed1972

Carbonic anhydrase polymorphism in a New Jersey population of the white-footed mouse Peromyscus leucopus.

Two electrophoretic forms of erythrocytic carbonic anhydrase were found to be controlled by one autosomal locus with two codominant alleles, CA(f) and CA(8). The gene frequencies for the CA(f) and CA(8) alleles were found to be.15 and.85, respectively, in a sample of 53 mice from Middlesex County, New Jersey. The observed genotypic frequencies indicated that the population was in Hardy-Weinberg equilibrium.

Alleles↗
PubMedDate not supplied

Prenatal diagnosis of the fra(X) syndrome.

The fra(X) syndrome is one of the most common causes of mental retardation, and validation of the reliability and feasibility of making the prenatal diagnosis of this disorder is important for genetic counseling and prevention. We have received a total of 74 amniotic fluid specimens for prenatal diagnosis of fra(X) from worldwide sources. Results were obtained on 68 specimens of which 43 had a documented family history of the fra(X) syndrome. Of the 43 specimens, 23 were male and 4 were prenatally diagnosed as being affected. On the basis of the results, several conclusions follow: 1.) At least 3 different tissue culture methods should be utilized. 2.) At least 150 cells should be scored, preferably 50 from each of 3 different tissue culture methods or 100 from each method if less than 3 methods are used. 3.) While the test appears to be reliable, it should still be considered to be experimental until larger numbers are obtained with completed follow-up of cases.

Amniotic Fluid↗