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La vida sexual de las personas con síndrome de Down (SD) u otros trastornos asociados con la discapacidad intelectual sigue siendo un tabú, con pocos relatos en la literatura. Los avances en el conocimiento de los aspectos causales y nosológicos, incluidas sus conquistas sociales, llevaron al fortalecimiento del movimiento inclusivo destinado a estas personas. En este artículo se presenta un caso inusual de un matrimonio de una mujer con SD que tiene un hijo. Esta mujer estudió en escuelas especiales y se comunica bien verbalmente. Presentó menarquía a los 13 años de edad, y demostró autonomía en el cuidado de su cuerpo. Ocho años atrás conoció a su actual esposo en una escuela especial. Después de 2 años de matrimonio, ella quedó embarazada de un varón sin este síndrome. La mujer es capaz de atender las necesidades de su hijo, responsabilidad que comparte con su madre, que fue la principal responsable de su educación hacia la autonomía. El cariotipo de la probanda reveló trisomía 21 con mosaicismo cromosómico. Se están produciendo nuevos logros sociales, incluido el establecimiento de relaciones afectivas perdurables. Las posibilidades de reproducción y el riesgo de recurrencia del SD de ben ser considerados en el consejo genético. El cuidado de todos los niños nacidos de estos matrimonios genera responsabilidades compartidas por estos padres especiales y sus familias (AU)

Sex life of people with Down syndrome (DS) or other conditions associated with intellectual disability is still a taboo, with few reports in the literature. Advances in knowledge of causal and nosological aspects, including its social achievements, have led to the strengthening of the inclusive movement aimed at those people. This paper presents an unusual case of successful marriage and reproduction of a woman with DS. The propositus studied in special schools and communicates well verbally. She presented menarche at age of 13, showing autonomy in caring for her body. Eight years ago she met her current husband at the special school she attended. Two years after the wedding, the proband became pregnant of a male child without the syndrome. She is able to take care of her child needs, sharing this responsibility with her own mother, who was primarily responsible for her education directed towards autonomy. The proband's karyotype revealed trisomy 21 with chromosomal mosaicism. New social achievements are occurring, among them the establishment of lasting emotional relationships. The reproductive chances and risks of recurrence of DS should be considered in genetic counseling. The breeding and rearing of any children born from these marriages become new responsibilities shared by these special parents and their families (AU)

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Loss of the Y chromosome in Drosophila has no impact on cell viability and therefore allows us to assay the impact of environmental agents and genetic alterations on chromosomal loss. To detect in vivo chromosome loss in cells of the developing Drosophila wing primordia, we first engineered a Y chromosome with an attP docking site. By making use of the ΦC31 integrase system, we site-specifically integrated a genomic transgene encompassing the multiple wing hair (mwh) locus into this attP site, leading to a mwh(+)Y chromosome. This chromosome fully rescues the mwh mutant phenotype, an excellent recessive wing cell marker mutation. Loss of this mwh(+)Y chromosome in wing primordial cells then leads to manifestation of the mwh mutant phenotype in mwh-homozygous cells. The forming mwh clones permit us to quantify the effect of agents and genetic alterations by assaying frequency and size of the mwh mosaic spots. To illustrate the use of the mwh(+)Y loss system, the effects of four known mutagens (X-rays, colchicine, ethyl methanesulfonate, and formaldehyde) and two genetic conditions (loss- and gain-of-function lodestar mutant alleles) are documented. The procedure is simple, sensitive, and inexpensive.

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Chromosomal mosaicism in human preimplantation embryos is a common cause of spontaneous abortions, however, our knowledge of its etiology is limited. We used multicolor fluorescence in situ hybridization painting to investigate whether paternally transmitted chromosomal aberrations result in mosaicism in mouse two-cell embryos. Paternal exposure to acrylamide, an important industrial chemical also found in tobacco smoke and generated during the cooking process of starchy foods, produced significant increases in chromosomally defective two-cell embryos, however, the effects were transient primarily affecting the postmeiotic stages of spermatogenesis. Comparisons with our previous study of zygotes demonstrated similar frequencies of chromosomally abnormal zygotes and two-cell embryos suggesting that there was no apparent selection against numerical or structural chromosomal aberrations. However, the majority of affected two-cell embryos were mosaics showing different chromosomal abnormalities in the two blastomeric metaphases. Analyses of chromosomal aberrations in zygotes and two-cell embryos showed a tendency for loss of acentric fragments during the first mitotic division of embryogenesis, whereas both dicentrics and translocations apparently underwent proper segregation. These results suggest that embryonic development can proceed up to the end of the second cell cycle of development in the presence of abnormal paternal chromosomes and that even dicentrics can persist through cell division. The high incidence of chromosomally mosaic two-cell embryos suggests that the first mitotic division of embryogenesis is prone to missegregation errors and that paternally transmitted chromosomal abnormalities increase the risk of missegregation leading to embryonic mosaicism.

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OBJECTIVE: To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH). METHODS: Totally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Y were analyzed. RESULTS: Among 51 embryos, 16 (31.4%) were mosaic, 12 (23.5%) were chaotic, and the remaining were either normal (27.5%) or non-mosaic abnormal (17.6%). The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from 12.5% in embryos

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The '13q-' syndrome shows widely variable manifestations. Investigation of the involvement of different tissues has never been reported in patients with 13q- syndrome previously. We describe a patient with mosaicism for del(13q) and clinical features of 13q- syndrome. The mother of the patient was professionally exposed to aniline colorants and glue components during the whole pregnancy. The patient had dysmorphic features, skeletal anomalies and brain malformations with agenesis of the corpus callosum, vermian hypoplasia and IVth ventricular system abnormalities. Eye examination revealed chorioretinal coloboma and irregular dispersion of retinal pigment in the right eye. The karyotype analyses and the molecular studies performed on peripheral lymphocytes, oral swab and cells of urinary tract were normal whereas a deletion of the long arm of chromosome 13 (13q13.2) was found in skin fibroblasts and in hair cells. We hypothesized that the 13q deletion arose during the third week after conception possibly due to a teratogenic effect and that tissue of mesodermal and ectodermal origin are involved. We suggest analysing a fibroblast karyotype when a diagnosis of 13q- syndrome is suspected on clinical ground. The role of teratogens in causing this type of mosaic chromosome abnormality also warrants further investigation.

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The effects of trifluoperazine on the mutagenicity of cyclophosphamide were examined in the progenies of Drosophila melanogaster males injected with 2 microliters of 5.0 mM cyclophosphamide and/or 0.1 mM trifluoperazine. The Muller-5 method was used to study the induction of sex-linked recessive lethals in five successive broods representing the different stages of spermatogenesis. Results should that both cyclophosphamide and trifluoperazine were proportionally toxic to the injected males. While cyclophosphamide was less toxic than trifluoperazine, it increased the frequencies of induced complete and mosaic lethals significantly (5% level) in all stages of spermatogenesis contrary to trifluoperazine which was non mutagenic and had only an additive effect over the toxicity of cyclophosphamide. The sizes of the mutated gonad tissue in the F1 mosaic female progenies of the males treated with cyclophosphamide alone ranged from 14% to 17% and of those treated with cyclophosphamide in association with trifluoperazine varied between 18% and 19%. Both complete and mosaic sex-linked lethals induced by cyclophosphamide treatments alone and in association with trifluoperazine were detected in singles and clusters.

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Single and repeated administration of ultralow doses of antibodies to erythropoietin did not increase the count of aberrant metaphases in bone marrow cells of BALB/c mice and were not genotoxic for Drosophila melanogaster wing cells in the test of somatic mosaicism.

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