Cytogenetic findings in fifty-five couples with recurrent fetal wastage

Balanced chromosomal translocations in parents and Müllerian abnormalities constitute defined causes of reproductive wastage. Fifty-nine couples with histories of recurrent abortion with or without fetal malformations were evaluated with cytogenetic studies and gynecography. In 44 of the couples with pure abortion histories of two or more spontaneous abortions, three (6.8%) balanced carrier parents were identified. In 11 couples with a mixed history of abortion plus fetal malformation, 3 (27.3%) had balanced translocations in one of the parents. The over-all incidence of Müllerian abnormalities in the group of 59 patients was 11.9%.     

Chromosome study of couples with repeated spontaneous abortions

The incidence of chromosomal abnormalities was evaluated in couples with a history of repeated abortions. The study included 14 couples with a history of 2 or more spontaneous abortions. Chromosome analysis was carried out on both marital partners from peripheral lymphocyte cultures. In every case, 30-62 metaphases were counted, and at last 20 karyotyped. Among the 14 couples, chromosome anomaly was found in 1 of the partners in 1 case. The patient, a 29-year-old female, was admitted to the hospital in the 36th week of her 10th pregnancy. In addition to an induced abortion and a premature delivery, her history included 7 spontaneous abortions at the 1st or 2nd month. Chromosome analysis of her peripheral blood revealed neither numerical nor structural aberations. In the 38th week, the patient gave birth ato a 3990 gm healthy boy whose karyotype of the cord blood also proved to be normal. The karyotype of the patient's husband revealed 45 chromosomes in 32 observed cells, and a chromosome was missing from each of the D and G groups. It was not possible to include in any of the groups a medium-sized, subterminal chromosome, diagnosed as D/G translocation. The husband proved to be a balanced D/G translocation carrier. When the pedigree was prepared, it was found that the younger sister of the husband had given birth to a child 1 month before term. Both the sister and her child were studied. The sister proved to be a balanced D/G translocation carrier. The child had translocational Down's syndrome: the D/G translocation occured in an unbalanced form. A table lists the results of chromosome investigations of cases of repeated abortions. Of 1066 married partners, chromosome aberations or variations responsible for multiple abortions were found in 70 (6.5%). Of these, 26 proved to be translocations. This incidence, 2-4%, is higher than the .4% in the general population. The results add credence to the argument that chromosome aberation may play a role in the causal background of recurring abortions. It is possible that with special staining procedures some aberations can be demonstrated in cases hitherto considered normal. In cases of repeated abortion, cytogenetic examination of both partners is routinely justified. In cases of chromosome aberations valuable data can be gained to serve as a basis for genetic counseling. When examining women with recurrent abortions, it should be possible to select patients to whom the possibility of intrauterine cytogenetic diagnosis can be offered.     

Genetic factors of recurrent abortions

A review of main genetic factors involved in pathogenesis of recurrent abortion is presented. The prevalence of chromosomal abnormalities in spontaneous abortions and the role of parental abnormalities of karyotype is pointed out, also in relation to many recent studies. The result of 354 karyotypes performed on couples with spontaneous abortion are presented; the prevalence of chromosomal abnormalities resulted 4.2%, with 73% of translocations, either reciprocal (40%) or robertsonian (33%), and 27% of inversions. The low number of minor abnormalities (0.8%) seems to confirm their poor clinical significance.     

Chromosome abnormalities in 118 couples with recurrent spontaneous abortions

Cytogenetic studies were carried out on 118 couples with recurrent spontaneous abortions. Four major chromosomal abnormalities were found including two 13/14 Robertsonian translocations, one t(7;12) and one t(1;10) reciprocal translocation. The incidence of chromosomal abnormalities in this study was 3.39%, which is lower than the mean value of the published data. The clinical significance of balanced translocations in recurrent reproductive loss is discussed.     

染色体异常与自然流产

染色体异常是自然流产的常见原因,包括夫妇染色体异常和胚胎染色体异常。其中夫妇染色体异常涉及结构异常,如相互易位、罗氏易位、倒位等;数目异常,如特纳综合征、克氏综合征等。胚胎染色体异常以非整倍体为主。文章将对染色体异常与自然流产的相关研究进展予以阐述。     

染色体异常与自然流产

染色体异常是自然流产的常见原因,包括夫妇染色体异常和胚胎染色体异常。其中夫妇染色体异常涉及结构异常,如相互易位、罗氏易位、倒位等;数目异常,如特纳综合征、克氏综合征等。胚胎染色体异常以非整倍体为主。文章将对染色体异常与自然流产的相关研究进展予以阐述。     

Recurrent pregnancy losses and parental chromosome abnormalities: a review

Summary. A compilation of the cytogenetic results taken from 79 published surveys of couples with two or more pregnancy losses (comprising 8208 women and 7834 men) showed an overall prevalence of major chromosome abnormalities of 2.9%. This is five to six times higher than that of the general adult population. In every group of chromosome abnormalities in the parents a predominance of female to male affected was noted (2:1). Approximately 50% of all chromosome abnormalities detected were balanced reciprocal translocations, 24% were Robertsonian translocations, 12% were sex chromosomal mosaicisms in females, and the rest consisted of inversions and other sporadic abnormalities. Parents with two or more idiopathic pregnancy losses should be karyotyped to aid in management and counselling. When a translocation or other abnormality (e.g. X chromosomal mosaicism) predisposing to an abnormal zygote is found, prenatal diagnosis is indicated in future pregnancies. Even when parental karyotypes are normal, prenatal diagnosis should be considered in subsequent pregnancies of parents with two or more pregnancy losses because of the high incidence of chromosome abnormalities in spontaneous abortions. For the same reason, if a single previous pregnancy loss is known to have been chromosomally aneuploid, parental karyotypes may have to be examined (depending upon the finding in the pregnancy loss), and prenatal diagnosis should also be considered in subsequent pregnancies.     

Cytogenetics of aborters and abortuses

783 aborters and 430 abortuses were studied in a prospective cytogenetic survey which attempted to link chromosome abnormalities and history of recurrent abortion. 425 female and 358 male spontaneous aborters and their 430 abortuses (310 were karotyped) showed 4 women and 2 men as balanced translocation carriers (3 Robertsonian and 3 reciprocal translocations) and a woman with an XXX karotype. 5 of the abortuses were successfully karotyped; 4 had inherited unbalanced translocation products, and the other had a balanced 13q14q translocation plus trisomy 18. Apparently, translocation chromosomes carried by aborters were transmitted to their abortuses. Structural chromosome abnormalities were found with higher frequency (.8%) among aborters than among the general adult population (.3%). Translocation carriers were more frequent among the aborters with histories of recurrent abortions (2.7%) as well as among aborters with a history of perinatal deaths (3.6%) than among those persons with no such histories (.6%). Data on 18 couples whose 2 or 3 successive spontaneous abortuses were karotyped are presented.     

Cytogenetic studies in couples with repeated spontaneous abortions

Chromosome studies were carried out on both partners of 509 couples with a history of two or more spontaneous abortions. 1) Twenty-six individuals (2.6%) were carriers of a major chromosome abnormality. This incidence is at least six to seven times higher than that in the general adult population. 2) Of these, 10 were reciprocal translocations, 10 robertsonian translocations and 6 numerical aberrations of gonosomes. None of the carriers showed abnormal phenotypes. 3) Chromosome aberrations were more frequent in the women than in their husbands. There were 19 abnormalities in females and 7 in males. 4) The use of banding techniques in chromosome analysis improves the detection of balanced reciprocal translocations. 5) Prenatal diagnosis was performed in 5 subsequent pregnancies of 4 balanced translocation carriers. The fetal karyotypes were 2 normal and 3 balanced translocations. It would seem reasonable to recommend chromosome analysis for couples with repeated spontaneous abortions.     

Translocations are infrequent among couples having repeated spontaneous abortions but no other abnormal pregnancies

During the years 1977 to 1986, cytogenetic studies were performed on 342 women and 297 men whose reproductive history included one or more first trimester spontaneous abortions. Thirty-nine women and 35 men experienced not only early fetal losses but also one or more stillborn infants, liveborn anomalous infants, or early neonatal deaths. Among the 303 women and 262 men evaluated solely because of repetitive abortions, only 1 woman and 1 man showed a translocation. Two translocations were detected among the 39 women and 35 men having not only repetitive abortions but also a stillborn infant, anomalous liveborn, or unexplained neonatal death. Only among the 25 women having abortions and other abnormal perinatal events was the frequency of translocations high (2/25 or 8%). Our data continue to indicate that balanced chromosomal translocations are relatively infrequent in individuals having repeated abortions but no other adverse perinatal outcome.     

Recurrent pregnancy losses and parental chromosome abnormalities: a review

A compilation of the cytogenetic results taken from 79 published surveys of couples with two or more pregnancy losses (comprising 8208 women and 7834 men) showed an overall prevalence of major chromosome abnormalities of 2.9%. This is five to six times higher than that of the general adult population. In every group of chromosome abnormalities in the parents a predominance of female to male affected was noted (2:1). Approximately 50% of all chromosome abnormalities detected were balanced reciprocal translocations, 24% were Robertsonian translocations, 12% were sex chromosomal mosaicisms in females, and the rest consisted of inversions and other sporadic abnormalities. Parents with two or more idiopathic pregnancy losses should be karyotyped to aid in management and counselling. When a translocation or other abnormality (e.g. X chromosomal mosaicism) predisposing to an abnormal zygote is found, prenatal diagnosis is indicated in future pregnancies. Even when parental karyotypes are normal, prenatal diagnosis should be considered in subsequent pregnancies of parents with two or more pregnancy losses because of the high incidence of chromosome abnormalities in spontaneous abortions. For the same reason, if a single previous pregnancy loss is known to have been chromosomally aneuploid, parental karyotypes may have to be examined (depending upon the finding in the pregnancy loss), and prenatal diagnosis should also be considered in subsequent pregnancies.     

Chromosomal analysis in Japanese couples with repeated spontaneous abortions

Balanced chromosome rearrangements have been found at an increased frequency in couples with pregnancy wastage, especially recurrent spontaneous abortions, compared with the general population. In the present study, chromosomal analysis of peripheral blood cells, as one of the routine examinations of patients with repeated reproductive wastage, was performed on both partners of 639 Japanese couples. Among the 639 couples, 32 major chromosomal anomalies (5.0%) and 23 minor chromosomal variants (3.6%) were found. Both partners of one couple had an abnormal karyotype. The 32 major anomalies consisted of 19 reciprocal translocations, 9 Robertsonian translocations, one large inversion, two triple-X females, and one Turner mosaicism. The 23 minor variants included 15 cases of pericentric inversion of chromosome 9. The total number of pregnancies in the 54 couples with chromosomal anomalies was 181, but they resulted in only 18 normal liveborn neonates, indicating a 90.1% abortion rate. The present statistical study indicates that major chromosomal anomalies seem to be involved in repeated reproductive wastage.     

309对早期自然流产夫妇的染色体分析——附4例世界首报核型

目的 :分析早期自然流产与染色体异常核型的关系。方法 :检测 30 9对早期自然流产夫妇双方的外周血淋巴细胞染色体核型。结果 :早期自然流产夫妇中异常核型检出率明显高于普通人群 ,总检出率为 6 .95 %。染色体异常 2 0例 :其中平衡易位 18例 (4例为世界首报核型 ) ,增加额外小染色体 2例 ;染色体异态 2 3例 :9号染色体臂间倒位 7例 ,D、G组随体变异 2例 ,9、16号次缢痕异染色质区变异 2例 ,Y染色体异态 12例。结论 :染色体异常和异态是导致早期自然流产的重要原因之一 ,对早期自然流产夫妇进行染色体检查是必要的 ,可以寻找流产原因 ,为优生优育提供依据     

Cytogenetic study of peripheral lymphocyte culture in couples with habitual abortion

We report on a cytogenetic investigation of lymphocytes in 241 couples and six women with at least three abortions. We found a balanced reciprocal translocation three times (1.2% of couples) and a balanced Robertsonian translocation twice (0.8% of couples). Four numerical aberrations of the gonosomes were detected (three of them as a mosaic), and one deletion Xq- as a mosaic. The heterochromatic region of the chromosomes 1, 9 or 16 was enlarged in 12 couples (4.9%). There was no couple with a pericentric inversion of the chromosomes 1 or 9. The enlarged Y-chromosome (five males) according to our results does not play any important role for the reproduction. Five translocations and one supernumerary chromosome each in one cell only indicate an enlarged frequency of breakage events in couples with habitual abortion.     

Etiologic factors and subsequent reproductive performance in 195 couples with a prior history of habitual abortion

A diagnostic screening program was applied to 195 couples with a prior history of habitual abortion (i.e., three or more consecutive abortions). Abnormalities were identified in 110 (56%) of the couples. Such identification was significantly more frequent in couples with primary habitual abortion than in couples with secondary habitual abortion (p less than 0.001) and also more frequent in couples with second-trimester abortions than in those with first-trimester abortions (p approximately equal to 0.01). The abnormalities most commonly observed were anomalies of the uterine body (15%), endometrial infections (15%), and cervical incompetence (13%). Hormonal dysfunctions were detected in 5%, and there were chromosomal aberrations in 3% of the couples. The women in the group showing abnormalities were offered surgical or medical treatment, and 80% of those who subsequently conceived carried their pregnancies to term. Among the couples with no abnormal findings, women receiving specific antenatal counseling and psychological support had a pregnancy success rate of 86%, as compared to a success rate of 33% observed in women who were given no specific antenatal care (p less than 0.001).     

Cytogenetic studies of spontaneous abortions in humans

Karyotypes were analyzed using directing method for chorionic villi chromosome preparation in 52 specimens from spontaneous abortions. A paralleled cytogenetic study of 51 specimens from induced abortions was carried out. Among 52 specimens from spontaneous abortions, 11 (21%) were chromosomally abnormal and 82% of these were found to have autosomal trisomies (3,14,16,19,20 and 21). Trisomy 16 was the most common abnormality accounting for 44% of trisomic abortuses. A double trisomic abortus with a 48, XX, +16, +20 karyotype was detected. These results showed that chromosome abnormality is an important cause of spontaneous abortion. The relationship between chromosomal abnormalities of spontaneous abortuses and the factors relevant to the abnormalities are discussed.     

Karyotypes of 1142 couples with recurrent abortion

Cytogenetic analysis was performed on 1142 couples with recurrent pregnancy loss. The frequency of major chromosomal abnormalities per couple was 4.8%. Among 771 couples who had only abortions, the rate of rearrangement did not correlate with the number of abortions. The highest incidence of cytogenetic abnormalities (6.6%) was found in 256 couples with abortion and a normal child. With regard to pregnancy outcome, no unbalanced fetal karyotype was found in prenatal diagnoses, and 40 normal children were born. The risk of unbalanced fetal karyotype is therefore low, but probably high enough for these couples to be offered the possibility of a prenatal diagnosis.     

染色体平衡易位携带者妊娠风险及妊娠结局的研究

目的 探讨染色体平衡易位携带者的妊娠风险及其妊娠结局.方法 194例染色体平衡易位携带者,根据平衡易位种类分成相互易位（135例）、非同源罗伯逊易位（52例）、同源罗伯逊易位（7例）3组.调查携带者生育史并随访诊断平衡易位后的妊娠情况,比较各组自然流产、先天缺陷及正常（或）平衡易位后代概率.结果 （1）194对夫妇共妊娠503例次,其中自然流产411例次（81.7%,411/503）;产前诊断胎儿异常而终止妊娠16例次（3.2%,16/503）;活产缺陷儿36例次（7.2%,36/503）;正常（或）平衡易位后代40例次（8.0%,40/503）.（2）相互易位、非同源罗伯逊易位、同源罗伯逊易位3组,活产缺陷儿比率分别为5.7%（20/350）、10.9%（14/128）、8.0%（2/25）,3组间相互比较,差异有统计学意义（P＜0.05）;3组正常（或）平衡易位后代比率分别为6.6%（23/350）、13.3%（17/128）、0,3组间相互比较,差异有统计学意义（P＜0.05）;而3组自然流产及产前诊断胎儿异常终止妊娠比率比较,差异无统计学意义（P＞0.05）.（3）52例次先天缺陷中活产36例次（69%）,经产前诊断确诊后引产16例次（31%）.27例次先天缺陷获得细胞遗传学诊断,唐氏综合征发生率为59%（16/27）.（4）相互易位组和非同源罗伯逊易位组共有39对夫妇得到40个正常（或）平衡易位后代,同源罗伯逊易位组无正常（或）平衡易位后代.40个正常（或）平衡易位后代中26个获得产前细胞遗传学诊断,正常核型6个（23%）,平衡易位核型20个（77%）.结论 染色体平衡易位携带者自然妊娠风险大,尤其同源罗伯逊易位携带者难以获得染色体正常（或）平衡易位的后代.     

Chromosomal aberrations in 2000 couples of Indian ethnicity with reproductive failure

Constitutional chromosomal aberrations contribute to infertility and repeated miscarriage leading to reproductive failure in couples. These aberrations may show no obvious clinical manifestations and remain undetected across multiple generations. However, infertility or recurrent spontaneous pregnancy loss, and/or genotypic/phenotypic aberrations may be manifested in the progeny during gametogenesis. The current study was a retrospective analysis to examine the chromosomal aberrations and prevalence in 2000 couples of Indian ethnicity with reproductive failure. Cytogenetic analysis via conventional G-band karyotyping analysis was carried out on phytohaemagglutinin stimulated peripheral blood lymphocytes, cultured in RPMI1640 medium. The chromosomes were enumerated as per International System for Human Cytogenetic Nomenclature at 500–550 band resolution, and recorded in the screening sheets. Chromosomal aberrations were detected in a total of 110 (2.78%) couples, with structural chromosomal aberrations in 88 cases including reciprocal translocations in 56 cases, Robertsonian translocations in 16 cases, inversions in eight cases, deletions in three cases, derivative chromosomes in five cases and numerical chromosome aberrations in 23 cases. The study emphasizes the importance of cytogenetic work up in both the partners associated with a history of reproductive failure. Genetic counselling with an option of prenatal diagnosis should be offered to couples with chromosomal aberrations.Alteration in the number or structure of chromosomes is associated with adverse obstetric outcome in the form of infertility or recurrent miscarriages. Most of these aberrations are balanced and hence, the person does not manifest any obvious clinical signs and symptoms. However, because of the formation of abnormal gametes (i.e. the eggs and sperm), these chromosomal aberrations result in infertility and recurrent spontaneous pregnancy losses. In the present study, we studied 2000 couples of Indian ethnicity with reproductive failure. Karyotyping was done on the blood sample of these couples using standard protocols. Chromosomal aberrations were detected in a total of 110 (2.78%) couples with structural chromosomal aberrations in 88 cases including reciprocal translocations in 56 cases, Robertsonian translocations in 16 cases, inversions in eight cases, deletions in three cases, derivative chromosomes in five cases and numerical chromosome aberrations in 23 cases. Thus, our study emphasizes the importance of cytogenetic work up in both the associated partners with history of reproductive failure which would help in better patient counselling and management.     

Cytogenetic studies in patients with reproductive failure

BACKGROUND: Cytogenetic studies in patients with reproductive failure AIM: To investigate the contribution of chromosomal abnormalities in sub fertility and in couples with repeated abortions. METHODS: Hundred and 13 couples who had at least two or more spontaneous abortions and 65 women and 63 men with infertility were analyzed cytogenetically. RESULTS: Major chromosomal rearrangements were found in 8% and minor variants in 6% in the study population. Major chromosomal aberrations were judged to explain 4.9% of recurrent abortions and 13% of infertility. Chromosomal abnormalities in infertile men occurred in 5% and in infertile women in 21.5%. The chromosomal abnormalities were structural (57%), numerical (18%) or mosaics (25%). CONCLUSIONS: Chromosomal aberrations in recurrent abortions are mostly structural ones and those in female infertility mosaicism of sex chromosomes. Turner's syndrome, Turner variants and XY females are detected as a cause of female infertility. The structural and numerical aberrations of either sex or autosomal chromosomes were found in infertile men.