نتایج جستجو برای: mosaicism
تعداد نتایج: 2889 فیلتر نتایج به سال:
Mosaicism is defined as the coexistence of cells with different genetic composition within an individual, caused by postzygotic somatic mutation. Although somatic mosaicism for chromosomal abnormalities is a well-established cause of developmental and somatic disorders and has also been detected in different tissues, its frequency and extent in the adult normal population are still unknown. We ...
Many studies estimate that chromosomal mosaicism within the cleavage-stage human embryo is high. However, comparison of two unique methods of aneuploidy screening of blastomeres within the same embryo has not been conducted and may indicate whether mosaicism has been overestimated due to technical inconsistency rather than the biological phenomena. The present study investigates the prevalence ...
BACKGROUND & OBJECTIVE There are potential risks of major birth defect in IVF (in vitro fertilization) pregnancy as well as IVF-ICSI (intra cytoplasmic sperm injection) pregnancies in comparison with naturally conceived human pregnancies. This increase risk could be due to either gonadotropins used for ovarian stimulation or in vitro culture conditions or multiple pregnancy or combinations of a...
The high abortion rate of 45,X embryos indicates that patients with Turner syndrome and 45,X karyotype could be mosaics, in at least one phase of embryo development or cellular lineage, due to the need for the other sex chromosome presence for conceptus to be compatible with life. In cases of structural chromosomal aberrations or hidden mosaicism, conventional cytogenetic techniques can be inef...
BLOOD GROUP MOSAICISM of human erythrocyte populations has been attributed in several instances to naturally occurring transplantation of blood cell precursors through vascular anastomoses formed in utero between fraternal twins. To account for generalized tissue mosaicism, a more fundamental disturbance affecting the formation of the zygote must be invoked. The first such case in man, attribut...
Testicular feminization syndrome (TFS) represents a well-defined form of male pseudohermaphroditism. The patients are of female legal sex. The habitus is completely and often attractively feminine, with well-developed breasts. There is absence of axillary and pubic hair. The external genitalia are female but with a blind vagina. At laparotomy the uterus and Fallopian tubes are found to be absen...
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