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Biomedical subjects

C G Palmer

Publications and source records attributed to C G Palmer.

At least 19 recordsLinked to original sources
PubMed1992

Ullrich-Turner syndrome with a small ring X chromosome and presence of mental retardation.

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference less than 10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A "triangular" face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45,X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS.

Adolescent↗
PubMed1992

Head circumference of children with Down syndrome (0-36 months)

This study provides statistically appropriate head circumference reference curves for males and females with Down syndrome (DS) from birth to 36 months of age. A total of 239 males and 182 females from five study populations, yielding a combination of cross-sectional and longitudinal data, were used for the analysis. The method of least squares was used to test the fit of the growth model y = a+bx+c[log(x + 1)], where x is age in months. These standardized curves should provide information of value in the medical, physical, and developmental management of children with DS.

Biometry↗
PubMed1992

A new nonrandom chromosomal abnormality, t(2;16)(p11.2;p11.2), possibly associated with poor outcome in childhood acute lymphoblastic leukemia.

We report a new, nonrandom t(2;16)(p11.2;p11.2) in childhood acute lymphoblastic leukemia (ALL). Three of 292 patients with childhood ALL studied at Indiana University Medical Center had this translocation. All three had additional chromosomal abnormalities at diagnosis and were classified as having low hyperdiploidy (47-49 chromosomes) with structural abnormalities. The patients, two boys and one girl, ranged in age from 3 to 13 years. Peripheral white blood cells (WBC) counts ranged from 1.8 to 107.4 x 10(9)/L, all were classified as French-American-British (FAB) type L1, and all had B-lineage ALL. Because all three patients have relapsed after first remissions of 2 years 8 months to 6 years, the t(2;16) may indicate a poor prognosis and more aggressive treatment may be indicated for such patients. Because this translocation was the sole abnormality in one clone of patient 2 at relapse, it may be considered the primary abnormality. Therefore, it may also be the primary abnormality in the other two patients, and the genes involved in the breakpoints may be important in leukemogenesis.

Adolescent↗
PubMed1992

Cytogenetic analysis in relapsed childhood acute lymphoblastic leukemia.

The nature of the cytogenetic abnormalities present at relapse of childhood acute lymphoblastic leukemia (ALL) and their relationship to the disease and the karyotype at diagnosis have not been clearly defined. This report describes cytogenetic analyses of 50/51 consecutive relapsed childhood ALL patients. Evolution of the karyotype was common, with structural abnormalities particularly frequent. Rearrangements involving chromosome 1 occurred frequently, particularly in patients with greater than 50 chromosomes. In patients with less than or equal to 50 chromosomes, structural aberrations were often unbalanced, leading to loss of genetic material, but these did not show a predominance of chromosome 1 abnormalities. These differences among the cytogenetic groups of ALL are an indication that the chromosomal abnormalities occurring in ALL reflect different biological events underlying this disease, and that different biological processes are involved in the several cytogenetic groups of ALL patients not only at initiation, but also during the progression and evolution of the disease.

Adolescent↗
PubMed1991

Partial deletion of chromosome 6p: delineation of the syndrome.

Here we summarize the clinical findings of five new patients and nine patients reported in the literature with deletions of the short arm of chromosome 6. The del(6p) syndrome appears to include the following clinical findings: mental retardation, microcephaly, abnormal sutures, broad nasal bridge, various eye and ear abnormalities, a short neck with excess skin folds, and a normal birth weight and length.

Abnormalities, Multiple↗
PubMed1991

Characterization of seven DA/DAPI-positive bisatellited marker chromosomes by in situ hybridization.

Seven dicentric bisatellited marker chromosomes, ascertained at amniocentesis, chorionic villus sampling, and in blood from an abnormal liveborn were characterized cytogenetically. All seven markers demonstrated brilliant bands by the DA/DAPI technique corresponding to C-band positive regions. Although some dicentric DA/DAPI-positive bisatellited markers have been identified as inverted duplicated 15s, recent literature has suggested that DA/DAPI lacks specificity for chromosome 15. Our evaluation of DA/DAPI-positive bisatellited marker chromosomes by in situ hybridization shows that some originate from chromosome 15 whereas DA/DAPI negative bisatellited markers may not be derived from 15. The morphological variations noted in our studies are discussed with respect to nomenclature.

Amniocentesis↗
PubMed1990

Deletions in chromosome 2 and fragile sites.

We report on 2 patients with de novo deletions of 2q and chromosome constitutions of 46,XY,del(2)(q32.3q33.3) and 46,XX,del(2) (q21q23.2), respectively. Comparisons of breakpoints of interstitial deletions show frequent correspondence to common fragile sites.

Cells, Cultured↗
PubMed1990

Cytogenetic studies of endometrial malignancies.

Thirty cases of endometrial malignancy were successfully studied cytogenetically. Twenty-four of the cases were endometrial adenocarcinomas. Twenty-three of these were stage I tumors, and the twenty-fourth was a stage IV tumor. Fourteen of the stage I adenocarcinomas had abnormal chromosomes, and nine had apparently normal chromosomes. No two tumors had an identical chromosomal rearrangement. Trisomy 1q was common however; 10 of the 14 tumors with abnormal chromosomes had a chromosome 1 abnormality. Clinical and pathologic data were available for 17 of these patients. There appeared to be no relationship between prognostic indicators and the tumor karyotype except for uterine size. Six cases of endometrial malignant mixed müllerian tumor (MMMT) of the homologous type were also analyzed cytogenetically. Three of these tumors had very abnormal karyotypes, and the remaining three had apparently normal chromosomes. Structural abnormalities of chromosome 1, 3, and 5 were present in all three tumors with abnormal karyotypes, but identical breakpoints or rearrangements were not observed.

Adenocarcinoma↗
PubMed1979

Sister chromatid exchange in lymphocytes from patients with acute lymphoblastic leukemia.

Sister chromatid exchange (SCE) frequencies were studied in peripheral lymphocytes from 16 patients with newly diagnosed acute lymphoblastic leukemia (ALL) prior to the initiation of chemotherapy. The mean SCE frequency (mean +/- SE) for these patients was 12.2 +/- 0.2 per metaphase, which was significantly higher (P less than 0.001) than the mean SCE score for 14 age-matched controls, 7.6 +/- 0.2. Five of these patients were studied again while they were receiving maintenance therapy consisting primarily of daily 6-mercaptopurine and weekly methotrexate. Their remission SCE levels remained significantly higher than controls (P less than 0.005). In addition, SCE levels were studied in 7 long-term survivors of ALL. Three of these patients had been receiving continuous maintenance therapy for at least 3 years. Their mean SCE scores were significantly greater than controls (P less than 0.005). The other 4 patients had finished their final course of chemotherapy at least 8 months prior to the time of sampling, and their mean SCE scores were not significantly different from controls (P greater than 0.10). These data indicate that untreated patients with ALL have increased SCE levels which remain elevated during periods of remission maintained with chemotherapy. However, long-term survivors of ALL who are in remission and off chemotherapy do not demonstrate significantly increased SCE frequencies.

Adolescent↗
PubMed1979

Position of the human X inactivation center on Xq.

In three women with a 46,XXq- chromosome constitution, the length of the deletion was expressed as the ratio of the remaining part of Xq to Xp c' over a + b. In one of them (KH) this ratio was 0.33, in another (GE) 0.59, and in the third (AP) the ratio fell between these values. The break in KH is more or less on the border of the Q-dark proximal region. A comparison with relevant X-autosomal translocations indicates that the X inactivation center lies near, but not at the border of, the Q-dark and the adjoining bright region (c and d).

Adult↗
PubMed1979

Nonhomologous associations of C-heterochromatin at human male meitoic prophase.

In human male meiotic prophase, nonhomologous pairings and connections between C-heterochromatic regions were demonstrated by C-banding and G-11 staining. Approximately 40% of the pachytene stages exhibited bivalent associations at regions of C-heterochromatin. Nonhomologous associations were seen between all possible morphological types of bivalents. Evidence is submitted suggesting that nonhomologous associations between regions of C-heterochromatin are a fairly common event in many organisms, including man, and the possible roles of this phenomenon in meiosis are discussed.

Azure Stains↗
PubMed1978

Clinical experience with trisomies 18 and 13.

The clinical, cytogenetic, dermatoglyphic, and postmortem observations of the 29 cases of trisomy 18 and 19 cases of trisomy 13 seen in the Department of Medical Genetics from 1963-76 are summarised. Chromosomes were studied in all and 30 were banded. One patient had tertiary trisomy 18 and 8 had translocations of chromosome 13. The features of these patients are described and the syndromes compared with each other and summaries found in the literature.

Chromosome Aberrations↗
PubMed1978

Meiotic analysis of a pericentric inversion, inv(7) (p22q32), in the father of a child with a duplication-deletion of chromosome 7.

In a family in which a large pericentric inversion of chromosome 7 is segregating, two of the four progeny of inversion heterozygotes show severe psychomotor retardation and have the karyotype 46,XX,rec(7),dup q,inv(7)(p22q32), derived from crossing-over within the inversion. Meiotic analysis in one of the heterozygotes revealed no evidence of inversion loops in well-spread pachytene cells. In approximately 20% of cells in diakinesis, the presumptive bivalent 7 had only one chiasma. Two alternatives to the reversed loop mode of meiotic pairing of inversions are proposed. Review of the literature supports the view that "small" pericentric inversions have a much better genetic prognosis than "large" pericentric inversions.

Abnormalities, Multiple↗