ABSTRACT
We reviewed 1347 cytogenetic studies performed in a period of eight years to analyze chromosomal translocations and their relation with reproductive failure. Twenty nine index cases were detected representing a global incidence of 2.2% thirteen (45%) were balanced reciprocal translocations between autosomes, thirteen (45%) were robertsonian translocations and three (10%) were X; autosomal translocations. The most frequent indication for the study were, for each group, respectively, recurrent abortion, a child with congenital malformations and ovarian dysfunction. Our results are compared with those of other authors and the mechanisms and figure risks for unbalanced offspring are discussed.
Subject(s)
Abnormalities, Multiple/genetics , Abortion, Habitual/genetics , Chromosome Aberrations/epidemiology , Infertility, Female/genetics , Adult , Chromosome Aberrations/genetics , Chromosome Disorders , Chromosomes, Human/ultrastructure , Female , Humans , Incidence , Infant, Newborn , Male , PregnancyABSTRACT
Between march 1988 and march 1991, 350 amniocenteses were performed as a part of the prenatal diagnosis program at the Instituto Nacional de Perinatología. Cytogenetic diagnosis was obtained in 348 cases (99.4%). A total of ten abnormal fetal karyotypes (2.9%) were detected: Down's syndrome, (5) Edwards' syndrome, (2) Turner's syndrome, (1) Klinefelter's syndrome (1) and chromosomal instability. (1) In addition, one carrier of a Robertsonian translocation, two balanced carriers of reciprocal translocations and three cases of true mosaicism, were also detected. In the group of patients studied for indications other than risk of chromosomopathy, one female fetus affected by congenital adrenal hyperplasia, was observed. There were two miscarriages, resulting in a post-procedural fetal loss of 0.57%.
Subject(s)
Amniocentesis/methods , Prenatal Diagnosis/methods , Amniocentesis/adverse effects , Amniocentesis/statistics & numerical data , Chromosome Aberrations/diagnosis , Chromosome Disorders , Female , Humans , Maternal Age , Metabolism, Inborn Errors/diagnosis , Pregnancy , Pregnancy, High-Risk , Prenatal Diagnosis/adverse effects , Prenatal Diagnosis/statistics & numerical data , Ultrasonography, PrenatalABSTRACT
Centromeric breaks and dissociation of Robertsonian translocations have been suggested to be the cause of a few cases of mosaicism. One possible explanation for dissociation could be that the point of reunion of the two acrocentrics would be a structurally fragile site. Mitomycin C (MMC) treatment of lymphocyte cultures from 6 patients having a Robertsonian translocation showed that in cases 1 and 2, who were already mosaics, MMC induced a statistically significant increase of the number of cells with the dissociated translocation. In the remaining cases a preferential centromeric break on the translocation was observed, indicating instability of the region. The relationship of monocentric and dicentric translocations, the viability of the cells resulting from the dissociation, and the clinical implications are discussed.
