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Biomedical subjects

D P Duckett

Publications and source records attributed to D P Duckett.

At least 19 recordsLinked to original sources
PubMed2002

Invasive testing for the karyotyping of mid-trimester intrauterine fetal death (IUFD): a pilot study.

INTRODUCTION: Aneuploidy remains a common cause of fetal loss after the first trimester. Conventional karyotyping from fetal solid tissues post-delivery unfortunately has a poor success rate particularly where the fetus is macerated. To overcome this we obtained amniocentesis and/or chorionic villus samples from mid-trimester intrauterine fetal deaths (IUFDs) prior to medical termination of pregnancy. SUBJECTS: Ten women with diagnosed IUFD between 12 and 24 weeks' gestation underwent amniocentesis and/or CVS performed after counselling. RESULTS: Successful karyotypes were obtained in all pregnancies. Five of the ten pregnancies were complicated by aneuploidy (two with trisomy 21, two with trisomy 18, and one with trisomy 13). CONCLUSION: The high rate of aneuploidy (50%) in this small cohort emphasises the need for karyotyping. A successful karyotype in all ten pregnancies demonstrates the value of offering these procedures before a termination of pregnancy. We would recommend the adoption of this approach in the management of IUFD occurring after the first trimester.

Adolescent↗
PubMed1999

Genetic amniocentesis: gestation-specific pregnancy outcome and comparison of outcome following early and traditional amniocentesis.

Amniocentesis remains the most common prenatal diagnostic invasive procedure for fetal karyotyping. During counselling prior to this procedure miscarriage rates are often quoted as a single figure. In this review of 2924 amniocenteses, we report that miscarriage rates vary with the gestational age at which the procedure is performed. The total miscarriage rate was 1.0 per cent after early amniocenteses (11 + 0-14 + 6 weeks) and 1.2 per cent after traditional mid-trimester amniocenteses (15 + 0-18 + 6 weeks). The rate was greatest (3.1 per cent) for amniocenteses performed after 18 + 6 weeks' gestation. The cumulative miscarriage risk increased from 0.03 per cent one week after the procedure to plateau at 1.1 per cent five weeks after the procedure. The preterm and still-birth rates following amniocenteses were similar in early and traditional mid-trimester amniocenteses but were significantly higher when amniocenteses were performed after 19 weeks' gestation. Although the incidence of talipes equinovarus was higher after early amniocentesis compared with traditional mid-trimester amniocenteses (1.4 per cent versus 0.2 per cent), none of the affected infants required corrective surgery. We conclude that counselling for this procedure should be tailored to each unit's unintended fetal loss rate based on cumulative rates. Such figures should be available to parents to assist them in their decision-making.

Adult↗
PubMed1998

Triplication of 15q11-q13 with inv dup(15) in a female with developmental delay.

A 4 year old female referred with developmental delay was found to have two de novo abnormal derivatives of chromosome 15, a supernumerary inverted duplicated marker chromosome (inv dup(15)) and an interstitial triplication of proximal 15q11-q13 or 14 in one of the two 15 homologues (trip(15)). Fluorescence in situ hybridisation (FISH) using probes within and flanking the Prader-Willi/Angelman syndrome critical region (PWASCR) confirmed the triplication in the abnormal 15 homologue. The inv dup(15) was dicentric, positive for IR39d which maps proximal to the PWASCR, but was negative for all the PWASCR FISH probes used. Results using polymorphic microsatellite repeats confirmed that the additional material in the trip(15) was maternal in origin and included several PWASCR loci. The presence of two de novo abnormalities involving the proximal region of 15q suggests a linked mechanism of origin.

Child, Preschool↗
PubMed1995

Brachydactyly and mental retardation: an Albright hereditary osteodystrophy-like syndrome localized to 2q37.

We report five patients with a combination of brachymetaphalangia and mental retardation, similar to that observed in Albright hereditary osteodystrophy (AHO). Four patients had cytogenetically visible de novo deletions of chromosome 2q37. The fifth patient was cytogenetically normal and had normal bioactivity of the alpha subunit of Gs (Gs alpha), the protein that is defective in AHO. In this patient, we have used a combination of highly polymorphic molecular markers and FISH to demonstrate a microdeletion at 2q37. The common region of deletion overlap involves the most telomeric 2q marker, D2S125, and extends proximally for a maximum distance of 17.6 cM. We suggest this represents a consistent phenotype associated with some deletions at 2q37 and that genes important for skeletal and neurodevelopment lie within this region. Screening for deletions at this locus should be considered in individuals with brachymetaphalangia and mental retardation. Furthermore, 2q37 represents a candidate region for type E brachydactyly.

Abnormalities, Multiple↗
PubMed1992

Trisomy/partial monosomy 13 mosaicism associated with relatively mild clinical malformation.

A female fetus with a rare de novo chromosome abnormality involving mosaicism with two cell lines with trisomy 13 and presumptive partial monosomy 13 due to a Robertsonian translocation and ring chromosome, respectively, was prenatally diagnosed. On termination this case, together with apparently the only other three reported cytogenetically similar cases, was found to have much less severe clinical abnormalities than might have been predicted. The possibility in these cases that the effects of the trisomy and monosomy for the common segment of chromosome 13 may have counterbalanced each other at the tissue level in embryogenesis thereby resulting in less disturbance of morphogenesis than would be expected for each type of imbalance acting in isolation is considered.

Abnormalities, Multiple↗
PubMed1990

Prenatal diagnosis of trisomy for the distal two-thirds of the long arm of chromosome 14 (q21----qter).

A de novo case of 'pure' trisomy 14q21----qter is described which was detected at amniocentesis following an abnormal ultrasound scan of a 25-year-old woman. This is apparently the largest distal 14q duplication reported in a case surviving beyond the first trimester. The infant appeared to have an association of clinical abnormalities previously observed in distal 14q trisomy and proximal 14q trisomy/mosaic trisomy 14.

Adult↗
PubMed1990

Expression of LFA-1 by a lymphoblastoid cell line from a patient with monosomy 21: effects on intercellular adhesion.

Monosomy 21 (M21) is a rare aneuploid condition which in certain cases leads to reduced levels of chromosome 21 gene products. We have prepared an Epstein-Barr virus lymphoblastoid cell-line (LCL) from patient with M21 who has immunological abnormalities, and analysed the expression of lymphocyte function-associated antigen-1 (LFA-1). This heterodimeric leucocyte integrin consists of CD11a (alpha) subunits non-covalently associated with CD18 (beta) subunits coded, respectively, by genes on chromosomes 16 and 21. To determine whether monosomy 21 results in decreased expression of LFA-1, monoclonal antibodies were used to compare the expression of CD11a and CD18 on the M21 LCL with LCL from trisomy 21 (Down's syndrome, T21), normal controls and a possible case of leucocyte adhesion deficiency. In addition, phorbol-ester-induced homotypic adhesion, an LFA-1-mediated effect, was compared in these LCLs. The results are consistent with a gene dosage mediated reduction of LFA-1 expression by the M21 LCL.

Antigens, CD↗
PubMed1990

Down's syndrome and fragile-X syndrome in a single patient.

A profoundly mentally handicapped patient is described with the karyotype 47,X, fra (X) (q27), + 21. Her phenotype demonstrates features of both Down's Syndrome and fragile-X syndrome. The authors believe only one other similar case has been described.

Adult↗
PubMed1990

Ocular findings in Angelman's (happy puppet) syndrome.

Patients with Angelman's syndrome have been reported to have ocular hypopigmentation and a number are now known to have a microdeletion of chromosome 15q 11----13. Detailed ocular examination of eight new cases revealed normal visual acuity and foveal reflexes, but a pigmentary deficiency which is limited to the choroid and iris stroma--both of neural crest origin. Patients with Prader-Willi syndrome have similar ocular features and many have a microdeletion of chromosome 15q 11----13. It is therefore possible that this region may influence neural crest development.

Abnormalities, Multiple↗
PubMed1989

Lethal presentation of mosaic tetrasomy 12p (Pallister-Killian) syndrome.

A lethally malformed neonate with mosaic tetrasomy 12p is presented. This is the third reported case of mosaic tetrasomy 12p to have died in the neonatal period. These three babies have shown a consistent phenotype characterized by dysmorphic facies and large diaphragmatic hernia. Mosaic tetrasomy 12p is usually not detectable from lymphocyte investigation, indicating that chromosome studies from cultured fibroblasts should be undertaken in neonates with multiple malformations which include a diaphragmatic defect.

Abnormalities, Multiple↗
PubMed1988

Maternal cell contamination in chorionic villus samples assessed by direct preparations and three different culture methods.

Presumptive maternal cell contamination (MCC) was monitored in identified male cases during cytogenetic comparison of direct techniques and three different culture regimens from 140 thoroughly dissected chorionic villus samples. Of the 66 identified male cases, 11 (16.7 per cent) showed MCC, the mean number of cells examined per case being 8.2 (direct) and 14.5 (cultures); in the direct preparations only one of a total of 457 cells examined was female, while preparations from cultures revealed MCC in 11 cases. Four of these had MCC in more than one culture regime and four had only a single female cell. The results showed that (1) dependence on the culture system alone would have given a diagnosis based on maternal cells in one (1.5 per cent) male case, thus underlining the danger of this approach (a similar undetected rate of misdiagnosis being expected in the female cases) and (2) MCC was significantly lower in cultures grown in Chang medium as compared with the other two regimes, McCoy's 5A + 15 per cent fetal calf serum and 1 per cent Ultroser G, and McCoy's 5A + 25 per cent fetal calf serum, the latter expressing the highest level of MCC.

Chorionic Villi Sampling↗
PubMed1988

A recombinant X chromosome in a short statured girl resulting from a maternal pericentric inversion.

A 7 3/4-year-old girl with short stature was found to have a recombinant (X),dup q chromosome resulting from an apparently unique pericentric inversion (X)(p11.2q26) present in her mother and maternal grandmother. The recombinant X chromosome was shown to be late replicating and the inversion X chromosome to be randomly inactivated. This appears to be only the eighth report (7 female, 1 male) of a recombinant resulting from an X pericentric inversion despite all diagnosed females having mild clinical abnormalities. Reasons for the rarity of such recombinant X chromosomes in man are examined.

Child↗
PubMed1988

Apparent monosomy 21 owing to a ring 21 chromosome: parental origin revealed by DNA analysis.

A three and a half year old mildly retarded boy is presented. Karyotyping showed monosomy 21 (45,XY,-21) in all 50 metaphase spreads examined from two lymphocyte cultures, and in 20% of cells examined from cultured fibroblasts; the remaining 80% of cells showed a ring 21 chromosome (46,XY,r(21)(p1q22]. Molecular studies using chromosome 21 specific DNA probes confirmed the monosomy in blood and showed that the ring 21 chromosome was paternal in origin. Parental karyotypes were normal.

Child, Preschool↗
PubMed1986

Trisomy 18 in a 13 year old girl.

A 13 year old girl with trisomy 18 is described. She showed profound mental and growth retardation, severe kyphoscoliosis, and unusual ocular features including discontinuous eyebrows, distichiasis, and blue sclerae.

Adolescent↗