Structural Chromosomal Abnormalities in Couples with Recurrent Pregnancy Loss

Abstract

A AB BS S T TR RA AC CT T O Ob bj je ec ct ti iv ve e: : Recurrent pregnancy loss is an important problem affecting couples trying to conceive. Genetic factors, particularly chromosomal abnormalities appear to be highly associated with reproductive loss. The frequency of presence of at least one partner, who is a carrier of a structural chromosome rearrangement, varies from 3% to 11% among couples with a history of recurrent pregnancy loss. The aim of this study was to introduce the cytogenetic data of couples that referred with recurrent pregnancy loss to our center. M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : Chromosome analyses were performed in 449 couples with more than one pregnancy loss using GTL banding. R Re es su ul lt ts s: : Chromosome abnormalities were detected in one partner in 19 of 449 couples. All chromosome abnormalities were structural, and 18 of them were balanced. Autosomal reciprocal translocations were the most frequent type (2.9%) of abnormalities. The unique Robertsonian translocation found in our study was t(13;14), which was observed in two patients. Chromosomal heteromorphisms were determined in 19.59% of patients. C Co on nc cl lu us si io on n: : The frequency of chromosomal abnormalities were found as 4.23% in our series. Cytogenetic investigation of couples with recurrent pregnancy loss is necessary as chromosomal abnormalities constitute a very important part of factors that cause pregnancy loss.K Ke ey y W Wo or rd ds s: : Cytogenetics; abortion, habitual; chromosomes Ö ÖZ ZE ET T A Am ma aç ç: : Tekrarlayan gebelik kayıpları, çocuk sahibi olmayı amaçlayan çiftleri etkileyen önemli bir sorundur. Genetik etkenler, özellikle de kromozom anomalilerinin üreme kayıplarıyla yakın ilişkisinin olduğu bilinmektedir. Tekrarlayan gebelik kaybı öyküsü olan çiftlerde, eşlerin en az birinin kromozom yapı anomalisi taşıyıcısı olma sıklığının %3-11 arasında değiştiği bildirilmektedir. Bu çalışmada, merkezimize tekrarlayan gebelik kayıpları nedeniyle başvuran çiftlerden elde edilen sitogenetik verilerin değerlendirilmesi amaçlanmıştır. G Ge er re eç ç v ve e Y Yö ön nt te em ml le er r: : Birden fazla gebelik kaybı olan 449 çiftte G bantlama kullanılarak kromozom analizi gerçekleştirildi. B Bu ul lg gu ul la ar r: : 449 çiftin 19'unda eşlerden birinde kromozom anomalisi saptandı. Tüm kromozom anomalileri yapı anomalisi, 18'i ise dengeli olarak bulundu. En sık gözlenen kromozom anomalisi türü otozomal resiprokal translokasyonlar (%2.9) olarak bulundu. İki olguda saptanan t(13;14) bu çalışmada gözle-nen tek Robertson tipi translokasyon oldu. %19.59 oranında kromozomal heteromorfizm gözlendi. S So on nu uç ç: : Bu çalışmada, tekrarlayan gebelik kaybı öyküsü olan çiftlerde kromozom anomalilerinin sıklığı %4.23 olarak bulunmuştur. Kromozom anomalileri tekrarlayan gebelik kayıp sebeplerinin önemli bir bölümünü oluşturduğundan, tekrarlayan gebelik kayıpları olan çiftlerde sitogenetik inceleme yapılması gereklidir.

Inheritance of a Chromosome 3 and 21 Translocation in the Fetuses, With One Also Having Trisomy 21, in Three Pregnancies in One Family

“…Especially when one of the parents is a carrier of a balanced reciprocal translocation, pregnancy may result in one of the three different types of offspring: a child with a normal karyotype, a child with a balanced reciprocal translocation, or a conceptus with an unbalanced karyotype that may lead to a spontaneous miscarriage or a live-born child with malformations and mental retardation. Cytogenetic findings do not only lead to RPL but also increase the frequency of bearing a malformed child, therefore, genetic counseling for subsequent pregnancies of couples who have balanced translocation is important [ 1 , 3 ].…”

“…These are responsible for a high incidence of infertility, pregnancy loss, mental retardation, behavioral abnormalities, morbidity and mortality. Carriers of reciprocal translocations have reduced fertility and thus form an increased risk of having a spontaneous abortion or an unbalanced karyotype in their offspring [ 1 , 3 , 5 – 11 ]. Pure trisomy due to non disjunction of chromosome 21 is responsible for 96.0% of Down Syndrome with a recurrence risk of less than 1.0%.…”