Search

The 3 affected children from 2 different wedlocks of the mother have been previously described (11). Search by FISH analysis in the mother revealed she is a carrier of balanced translocation of clear terminal G bands of equal sizes of the long arms of chromosomes 10 and 14. Chromosomal slides of the last child (Patient 3) could be analysed by fish and revealed that he did inherit the derivative chromosome 10. He had a partial trisomy 14 and a partial deletion of the long arm of chromosome 10. The clinical pictures correspondence to the possibly abnormal karyotypes will be discussed.

We describe a family with an autosomal dominant form of retinal-cerebellar atrophy. There is an extreme variability in age of onset and severity of the clinical symptoms: some patients remain nearly asymptomatic throughout their entire life; others develop severe retinal and cerebellar symptoms after the age of 35 years; others suffer from a severe disorder with onset in adolescence and death during the third decade of life; in others the onset is in early childhood with prevalence of cerebellar symptoms. There is neither dementia nor epilepsy in any of the patients. Four out of five autopsies showed, a severe retinal atrophy, and all five autopsies were also characterized by (1) a cerebellar atrophy affecting the spinocerebellar and olivocerebellar tracts, the cerebellar cortex and the efferent cerebellar pathways, (2) an involvement of the pyramidal pathways and of the motor neurons of brain stem and spinal cord, and (3) an atrophy of the subthalamic nucleus and to a much lesser extent of the pallidum, with also some damage to the substantia nigra. The posterior columns are much less affected except in one patient. In this family, we have excluded linkage with the two loci for spinocerebellar ataxia, i.e., SCA1 on chromosome 6p and SCA2 on chromosome 12q as well as with the locus for Machado-Joseph disease (MJD) on chromosome 14q. A genome-wide search is currently being performed to detect the disease locus responsible.

1000 cases of genetic counseling have been reviewed. Most patients are sent to the genetic center by gynecologists (68.4%), mostly because of a personal or previous familial history (64%). This previous history concerns mainly congenital malformations (44%, 283/640) and mental retardation (24%, 154/640). Generally, the patients consult outside a pregnancy, nevertheless one fourth comes after conception and this occurs more often when the proband is a family member (38% versus 19% when the proband is a spouse and 20% when the proband is a child). Ten percent of the patients knowing they could be at risk because spouse or child is affected consult after having already had a child or having had another child. The mode of inheritance of the diseases for which patients with previous family history consult is as follows: mendelian inheritance (36%), multifactorial inheritance (19%), chromosomal defect (18%), non genetic (5%), variable inheritance (2%), unknown (15%) and insufficient information (5%). The majority of patients coming for previous familial history could be tranquilized, the recurrence risk was either small or minimal. In 2.6% of the cases, a high recurrence risk has been given and the risk could not be evaluated in 7% of the cases. The importance of genetic counseling is stressed by the fact that antenatal diagnosis could be proposed to half of the patients with a recurrence risk equal or higher than 1%.

In the literature dealing with the impact of genetic counsel in the reproduction decision, two aspects are discussed: 1. memorization and appraisal of the recurrence risk, chosen options for family planning, appraisal of genetic counsel by the patients 2. mechanisms of decision making and psychological impact of genetic counsel.

The authors report the results of chromosomal analyses performed on 6235 amniocenteses and 559 choriocenteses. Whereas the frequencies of chromosomal anomalies observed respectively on amniocenteses and choriocenteses did not differ significantly, the comparison of the types of aberrations found revealed, in chorion villi, a relatively high proportion of lethal anomalies, never encountered in amniocyte cultures. Furthermore, chromosomal mosaicism was observed 10 times more frequently on chorion villi than on amniotic cells. These results are globally comparable to those reported in other surveys. In view of literature reports of discordances between fetal chorionic karyotypes, never found in amniocenteses, rapid karyotyping from chorion villi is not as reliable as from amniotic cells. Taking into account the risk of cytogenetic discordance specific to choriocentesis, it is recommended that this method be strictly limited to pregnancies with high genetic risk.

The authors tried to determine a dose-effect relation between the concentration of Bleomycin and the number of chromosomal aberrations "in vitro" in human lymphocytes during 48 h cultures. Concentrations of 1 gamma/ml, 2 gamma/ml, 10 gamma/ml and 20 gamma/ml were used. The number of normal cells seems to decrease according an exponential function; at a concentration of 20 gamma/ml, 15 p. 100 of the cells were apparently normal and this rises the problem of chemotherapeutic agent resistance. The number of one hit and two hit damages increases according to the dose of Bleomycine but it was not possible to determine a mathematic relation of the phenomenon. Like viruses and others chemicals, Bleomycin was responsible for "pulverisation" of chromosomes in several cells.

We report on two sibs with Dandy-Walker malformation and tetramelic postaxial polydactyly. We conclude that this is a new autosomal recessive syndrome.

Cytogenetic analyses performed in infertile men showed a frequency of genetic abnormalities definitely higher than in normal population. Cytogenetic analysis is perfectly justified in infertile men with normal phenotype.