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Biomedical subjects

J Dagan

Publications and source records attributed to J Dagan.

At least 19 recordsLinked to original sources
PubMed2001

Prenatal diagnosis of sex chromosome aneuploidy: possible reasons for high rates of pregnancy termination.

Sex chromosome aneuploidy (SCA), when detected in amniocentesis, is usually an unexpected result of a test carried out for another purpose. For most SCAs, the prognosis is milder and less predictable than trisomy 21, and therefore parents are faced with a difficult decision regarding the option of pregnancy termination. While studies from Europe and the USA report a declining trend in termination rates for SCA, our local experience is different. During the period 1989-1998, we diagnosed 60 SCA (including mosaics) in 20 106 amniocenteses (0.29%) and 48 (80%) of these pregnancies were terminated, a significantly higher proportion than has been reported in Europe and the USA. The present study shows that the difference between our experience and others' may be related to differences in cultural norms and values. Thirty women were interviewed, of whom 23 terminated and seven continued the pregnancy. Interview analyses showed that the main reason behind the decision to terminate the pregnancy was associated with the parents' fear of non-specific abnormality of the child, and concerns about abnormal sexual development. Although genetic counseling practised in our center aims to be non-directive, 56% of the women reported that the counseling was either directive towards termination, or that they at least felt that the counselor's attitude was pro-termination. Most women (93%) reported themselves as having come to terms with their decision.

Abortion, Induced↗
PubMed1997

A syndrome including thumb malformations, microcephaly, short stature, and hypogonadism.

We report on eight patients from seven different families affected with a syndrome which includes thumb defects, short stature, microcephaly, and mental retardation. Most of the patients had additional malformations, in particular amenorrhoea and azoospermia in the adults. There were no haematological manifestations and the chromosomes were normal without evidence of breakage even after stimulation. In five of the cases the probands' mother received hormonal treatment before or at the beginning of her pregnancy or both. The syndrome may be inherited as an autosomal recessive trait since the patients included both males and females and their parents were related in most cases. In addition, supporting this possibility, they all originated from a small village which may be considered as an isolate. However, in all cases but one, only one person was affected in each family and there was a significant apparent excess of healthy sibs of the probands. These observations may be the result of the variability of the syndrome or a more complex type of inheritance.

Abnormalities, Multiple↗
PubMed1996

t(15;21)(q15;q22.1) pat resulting in partial trisomy and partial monosomy of chromosomes 15 and 21 in two offspring.

Two sibs, carriers of unbalanced products of the translocation t(15;21)(q15;q22.1) pat, are described. The sister had Prader-Willi syndrome due to deletion 15 (pter > q15) and partial trisomy 21 (pter > q22.1); her brother had partial trisomy 15 (pter > q15) and partial monosomy 21 (pter > q22.1). The translocation breakpoint on chromosome 21 was located proximal to the SOD1 gene, within a region of 4.0 cM (2.3 Mb) between the loci D21S217 and D21S213. The correlations between the clinical presentation and the molecular findings of the two sibs are discussed in relation to other patients with partial trisomy and monosomy 21.

Adolescent↗
PubMed1995

Paracentric inversion X(q21.2q24) associated with mental retardation in males and normal ovarian function in females.

We describe a familial paracentric inversion (X)(q21.2 q24) in a family with 2 male and 2 female carriers. The males were mentally retarded and the females were normal with normal ovarian function. It is suggested that a recessive mental retardation (MR) gene was disrupted by one of the inversion breakpoints, although an X-linked MR gene which by chance is linked to the inv(X) could not be ruled out. In the female carriers of the paracentric inversion a random X-inactivation was demonstrated. The normal ovarian function is an exception to the concept of "critical region" at Xq13-q26.

Adolescent↗
PubMed1995

Simultaneous formation of inv dup(15) and dup(15q) in a girl with developmental delay: origin of the abnormal chromosomes.

Two de novo abnormal derivatives of chromosome 15, inv dup(15) and dup(15q) were found in a girl with developmental delay and mild dysmorphological signs. Fluorescence in situ hybridization, using DNA probes of the Prader-Willi/Angelman syndromes (PWS/AS) critical region and chromosome-15-specific alpha-satellite, combined with molecular analysis using dinucleotide repeat polymorphisms within the PWS/AS region and the parent-of-origin specific methylation sites at the locus D15S63, shed light on how the abnormal karyotype was formed. We suggest that a translocation between the two homologues of maternal chromosomes 15 resulted in the formation of dup(15q) and two reciprocal products: an acentric fragment of 15q that was lost and a centric fragment that underwent U-type reunion to form inv dup(15).

Angelman Syndrome↗
PubMed1993

Isochromosome 18p in a mother and her child.

We present a familial case of isochromosome 18p [i(18p)] as a supernumerary chromosome. The mother, who is a mosaic for i(18p) with partial tetrasomy 18p syndrome, transmitted the isochromosome to her only child. The child has the full syndrome of tetrasomy 18p. This is the first case of mosaicism i(18p) in an adult patient with clinical manifestations.

Adult↗
PubMed1991

The ATC (ataxia-telangiectasia complementation group C) locus localizes to 11q22-q23.

The multisystem autosomal recessive disease ataxia-telangiectasia (A-T) is determined by several genes, as evidenced by the existence of four complementation groups in this disorder. Using linkage analysis, the ATA (A-T complementation group A) gene was previously localized to chromosome 11, region q22-q23. Analysis of the segregation of RFLP markers from this region in a Jewish-Moroccan family assigned to group C indicates that the ATC (A-T complementation group C) gene localizes to chromosome 11q22-q23 as well.

Ataxia Telangiectasia↗
PubMed1989

Isodisomy of chromosome 7 in a patient with cystic fibrosis: could uniparental disomy be common in humans?

Maternal isodisomy for chromosome 7 was observed in a 4-year-old cystic fibrosis patient with very short stature. In an examination of 11 DNA polymorphisms spanning the entire length of chromosome 7, no paternal contribution could be shown in seven informative loci. Paternity was examined with probes for five polymorphic loci on the Y chromosome, for the pseudo beta-globin locus on chromosome 11 and by Jeffreys's hypervariable probes. The results with the latter gave a probability of 3.7 x 10(-9) for nonpaternity. Chromosomal examination revealed a centromeric heteromorphism of chromosome 7 in the mother, for which the proband was homozygous. Isodisomy of the patient was thus shown for the entire length of a maternal chromosome 7. The mechanisms leading to this isodisomy involve at least two events of abnormal cell division, events that may be meiotic, postzygotic, or both. This proband is the second reported maternal isodisomy; both were detected through homozygosity for CF. Both patients had short stature, which could have been caused by parental imprinting, since similar results have been observed in isodisomic mice. Homozygosity due to uniparental descent in man should be kept in mind as a mechanism for recessive disorders, especially for chromosome 7.

Child, Preschool↗
PubMed1984

Hysteroscope for CO2 laser application.

Endoscopic laser surgery is becoming more common with the development of suitable instruments. A hysteroscope designed for use with a Sharplan CO2 laser is described in detail. The method of application, results of preliminary experience, and possible indications are discussed.

Endoscopes↗
PubMed1984

The SHARPLAN family of CO2 lasers for surgery.

The SHARPLAN laser systems are available with a full range of different powers: a 25 watt office system, a 40 watt and a 60 watt system for general surgery and an 80 watt for high power needs like neurosurgery, all powers measured at tissue. A full range of accessories is available for microsurgery enabling adaptation to the most popular surgical microscopes for cavitational surgery. Super-pulse models are available, minimizing the thermal damage to the tissue exposed to the laser. The interaction of the laser with living tissue and its specific use in neurosurgery are discussed.

Carbon Dioxide↗
PubMed1984

A complex three way translocation resulting in two sibs with partial trisomy 3p23----3pter.

A male infant with multiple congenital anomalies and psychomotor retardation was found to have a translocation resulting in partial trisomy for the distal part of chromosome 3p. An older sister with similar clinical findings had an identical karyotype. Chromosome studies in the phenotypically normal parents revealed a balanced translocation in the mother involving chromosomes 3, 11, and 18. An identical translocation was found in one of the normal children.

Abnormalities, Multiple↗