Reproductive outcome of a case with familial balanced translocation t(3;6): implications for genetic counseling

ABSTRACT. Balanced translocation is a common structural chromosomal rearrangement in humans. Carriers can be phenotypically normal but have an increased risk of pregnancy loss, fetal death, and the transmission of chromosomal abnormalities to their offspring. Existing prenatal screening technologies and diagnostic procedures fail to detect balanced translocation, so genetic counseling for carriers remains a challenge. Here, we report the characteristics of chromosomal reciprocal translocation in 3807 amniocentesis cases. Of the 16 detected cases of fetal reciprocal translocation, 8 cases (50%) showed positive biochemical marker screening; 3 cases (18.75%) were the parental carriers of a chromosomal abnormality; 2 (12.5%) were of advanced maternal age, 2 (12.5%) had a previous history of children with genetic disorders, and 1 case (6.25%) was associated with positive soft markers in obstetric ultrasound. Chromosomes 5 and 19 were the most commonly involved chromosomes in balanced translocations. Of the 13 2 H.G. Zhang et al. Genetics and Molecular Research 15 (3): gmr.15038556 cases with fetal balanced translocations, 8 (61.5%) were inherited from a paternal chromosome, 3 (23.1%) from a maternal chromosome, and 2 (15.4%) cases were de novo. The incidence of balanced translocation at amniocentesis was 0.42%. Male carriers of reciprocal chromosome translocation appear to have a higher chance of becoming a parent of a child born by normal childbirth than female carriers.

Section: Methodsmentioning

confidence: 99%

Balanced reciprocal translocation at amniocentesis: cytogenetic detection and implications for genetic counseling

Zhang

Tian

et al. 2016

“…Cultures were incubated at 37°C for 72 h and before being treated with 20 μg/mL colcemid for 1 h. G-banding of metaphase chromosomes and karyotype analysis were performed according to our previously published methods (Zhang et al, 2015).…”

Section: Cytogenetic Analysismentioning

confidence: 99%

Male carriers of balanced reciprocal translocations in Northeast China: sperm count, reproductive performance, and genetic counseling

Zhang¹,

Wang²,

Li³

et al. 2015

ABSTRACT. Balanced chromosomal translocations in men can cause failure of spermatogenesis owing to meiotic impairment. Male carriers may exhibit normozoospermia, although clinical manifestations can include oligozoospermia or azoospermia, oligozoospermia or normozoospermia. Here, we reported the characteristics of balanced reciprocal translocations in men from northeastern China, and explored the relationship between sperm count and reproductive performance, to enable informed genetic counseling. The frequency of balanced reciprocal translocations was found to be 1.62%. Semen analysis showed that 5.9% of male carriers had azoospermia, 43.1% had oligozoospermia, and 51.0% had normozoospermia. Of the 25 men with a balanced reciprocal translocation and azoospermia or oligozoospermia, chromosome 1 was the most commonly often involved in the translocation. However, in the 26 normozoospermic men with a balanced reciprocal translocation and normozoospermia, chromosome 3 was most commonly implicated. Fifty percent of men with a balanced reciprocal translocation conceived a pregnancy that went to term. Our data suggest that of all chromosomes, Reciprocal translocations in northeastern Chinese men 18793©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (4): 18792-18798 (2015) chromosomes 1 and 3 are the most commonly involved chromosomes in balanced reciprocal such translocations in northeastern Chinese men. Karyotype analysis should be performed for men with azoospermia, oligozoospermia, and those in couples having suffered recurrent miscarriages. Natural conception should be discussed during genetic counseling for male carriers of balanced chromosomal translocations with normozoospermia.

“…Peripheral blood (0.5 mL) was collected from all patients in sterile tubes containing 30 U/mL heparin; these samples were subjected to G-banding, using cultured peripheral blood lymphocytes as described previously (Zhang et al, 2015). At least 20 metaphases were analyzed per patient.…”

Section: Cytogenetic Analysismentioning

confidence: 99%

Structural chromosomal abnormalities in couples in cases of recurrent spontaneous abortions in Jilin Province, China

Ht¹,

Zhang²,

Zhan³

et al. 2016

ABSTRACT. Recurrent spontaneous abortions (RSAs) occur in approximately 15 to 20% of all clinically recognizable pregnancies. Structural chromosome abnormalities result in increased risk of pregnancy loss. Parental chromosomal abnormalities are an important genetic cause of RSAs. Some cytogenetic investigations have been performed in various countries and regions to determine the pattern of chromosomal abnormalities in parents with RSAs. The aim of this study was to report the prevalence and type of structural chromosomal abnormalities in couples in cases of RSAs in Jilin Province, China. The prevalence of structural chromosomal abnormalities in these couples was 2.98%. The number of female carriers with balanced chromosomal aberrations significantly exceeded that of such male carriers, and the ratio of female/male carriers was approximately 2:1. The number of abortions in the case of female carriers was more than that for male carriers before the structural chromosome abnormality was diagnosed. This indicates that genetic counseling for couples with structural chromosomal abnormalities should consider the gender of the carriers.