Análise citogenética e molecular do gene FOXO3 em síndrome mielodisplásica

Pós-graduação em Genética - IBILCE

Correlação entre aneuploidia cromossômica em espermatozóides e taxa de implantação embrionária: subtitulo

Infertility is directly related to chromosomal abnormalities in germ cells. Among them, the aneuploidies are the most frequent chromosomal abnormalities and responsible for embryo implantation failures, miscarriages, fetal losses and newborns with congenital malformations, mental disability and neuropsychomotor developmental delay. Male patients with normal somatic karyotype may present different rates of aneuploidies in sperm, resulting in abnormal embryos. This study aimed to correlate the frequency of chromosomal aneuploidies in spermatozoa with embryo implantation rate in couples undergoing assisted reproductive techniques. The methodology has included chromosomal analysis by GTG banding and molecular cytogenetic study using Fluorescent In Situ Hybridization technique for evaluation of chromosomes 9, X and Y in germ cells of 22 patients referred to the Human Reproduction Service of the Clinical Hospital FMRP-USP. Embryo implantation rates were determined by hormonal evaluation in maternal peripheral blood and ultrasound confirmation. Two patients presented abnormal karyotype, characterized by polymorphism of the heterochromatic region of the long arm of chromosome 9 and a satellite in the short arm of chromosome 22. Both alterations, usually considered variants of normality, have been related to infertility phenotype and miscarriages. Significant differences were detected between couples who presented pregnancy (group 1) and couples with embryo implantation failure (group 2), with higher frequency of aneusomy and diploidy of chromosome 9, as well as total aneuploidy in sperm of group 2 patients. Our results suggest a correlation between aneuploidy and embryo implantation rates, since the infertile group with reproductive failure has showed higher frequency of aneuploidy. Screening for aneuploidies detection in male germ cells should be included in order to decrease embryo implantation failures, miscarriages and fetuses with chromosomal ...

Estudo citogenético em equinos para detecção de portadores de monossomia do cromossomo X

A cytogenetic study of 22 mares with fertility has showed that four of them had 63,X/64,XX mosaicism. The X-chromosome has presented the expected interstitial heterochromatic C - banding located in the long arm, besides of the usual centromeric band. The great variation of clinic signs observed in mares with mosaicism, could be due to the type of zygote or the time the mosaicism occured.

Estudo das alterações cariotípicas, do rearranjo gênico BCR/ABL e do cromossomo 20 em leucemias

Leukemia is a genetic disease from a noncontrolled abnormal process of the hematopoietic cells' differentiation and proliferation. Some alterations of structure and number of chromosomes have been well and specifically observed in leukemia. The detection of these alterations is highly significant in providing the patients' diagnosis, prognosis and treatment as well as the understanding of the genetic bases of this disease. The purpose of this work is to study some chromosomal alterations in peripheral blood and/or bone marrow in patients with different leukemia types by means of conventional cytogenetic techniques, and also to investigate the presence of BCR/ABL gene rearrangement and some alterations in chromosome 20 by the FISH technique. Samples of peripheral blood and/or bone marrow of 28 patients, who were not under chemoor radio-therapeutic treatment, were studied: 15 with CML, 11 with AML and 2 with ALL. The alteration most frequent was t(9;22) in the CML, whose presence or absence was related to a good or bad prognosis, respectively. A case of AMI showed inv(16)(p13q22), related to a good prognosis. Some alterations not reported previously in the literature were found, such as the trisomy in chromosome 2 associated to chromosome Ph showing some disease progress in one of the CML cases and t(5;16)(q13;q22) in an AML patient. One of the cases was submitted to an allogeneic hone marrow transplant. The monitoring after the 23 rd day of transplant, detected 95% of the donor cells suggesting the procedure had succeeded. Two patients, an AMI and the other ALL, showed trisomy of chromosome 20 in the neoplastic cells. The results showed the importance of the cytogenetic analysis in relation to leukemia, its direct benefits to the patients and the biological mechanisms involved in this disease. They also allowed the introduction in the Genetic Service of FAMERP techniques to obtain the bone marrow metaphases and the FISH technique.

Locus no cromossomo 19 influencia positivamente o número de oócitos recuperados em ciclos estimulados

Objective: To evaluate if identified loci associated with normal age of menopause variation and early menopause can account for the poor response to controlled ovarian stimulation. Methods: A total of 71 patients, with age ≤ 35 years old, undergoing intracytoplasmic sperm injection were tested for three of the four newly identified genetic variants associated with normal variation in menopausal age and early menopause. Patients were divided into two groups: poor responder group (PR group, n=21) and normoresponder group (NR group, n=50). The influence of risk allele frequency on the response to controlled ovarian stimulation (COS) was evaluated. Logistic regression models were used. Results: There was no significant difference in the incidence of the genetic variants between NR and PR group. The risk allele for chromosome 19 variant (rs4806660) demonstrated a protective effect. The presence of a risk allele, either in homozygosis or in heterozygosis, was associated with an increased response to COS, resulting in an elevated number of follicles (Coef: 2.54, P= 0.041) and retrieved oocytes (Coef: 1.41, P= 0.041). Conclusions: Genetic variants rs244715, rs9379896 and rs4806660 are not risk factors for poor ovarian response. Instead, rs4806660 is associated with higher number of follicles and retrieved oocytes. It could be hypothesized that rs4806660 is associated with an increased response to gonadotrophin stimulus. © Todos os direitos reservados a SBRA - Sociedade Brasileira de Reprodução Assistida.