Parental Miscarriages and balanced chromosomal anomalies

We estimate at 15% the number of pregnancies that do not succeed to term and 1% the proportion of couples who have at least three miscarriages consult in gynaecology, thus answering the usual definition of the abortive disease. The balanced chromosomal anomalies constitute one of the reasons of the repeated spontaneous abortions. The chromosomal translocations robertsonian or reciprocal are the most the anomalies observed, because they predispose to the production of genetically not balanced gamete and non viable fetuses. We report 5 observations of couples having repeated miscarriages secondary to balanced translocations at one the parents, among the 400 couples followed in the consultation of medical genetics from 1992 to 2004. The karyotype has been achieved at the couples with at least three miscarriages. We identified 5 chromosomal abnormalities: two reciprocal translocations: t[7;8]; t[l;15] and three robertsonian translocations: t[22q22q]; t[14;21]; t[13;14]. The genetic advice is according to the type of the translocation, the localization of the points of break and also of the viability or not of the malformed fetus. It aims to explain to the couples the mechanism responsible for the failure of reproduction, to make them understand them the inefficiency of the hormonal treatment and the theoretical possibilities to lead pregnancies to term. It also permits to estimate the risk of birth to a sick child and to propose to the parents the different means of follow-up of these much desired pregnancies. In this work, we discuss the mechanism by which these anomalies produce the miscarriages and the interest of the chromosomal analysis at the couples who consult for an abortive disease

Mental retardation in genetic consulting

We report in this article, analysis of the etiology of 510 observations of mental retardation seen in genetic service. The more part of our patients are children addressed to us for cytogenetic analysis or for opinion diagnosis by reason of a dysmorphic aspect. Etiological diagnosis has been determined in 441 cases. The mental retardation was chromosomal in origin in 426 cases, with in particular 398 children with Down syndrome, eleven trisomly 18, three syndromes of Wolf-Hirschhorn, one syndrome of Williams, three anomalies of gonosomes and ten chromosomal structure aberration. The mental retardation was of gentic origin in 15 patients with a transmission linked to the X chromosome in 8 cases, autosomal recessive transmission in 6 cases and autosomal dominant transmission in 1 case. The knowledge of the precise etiology of the mental retardation permits to pick up the handicapped person and especially it allows the geneticist to lavish an adequate genetic advice to the family members