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The authors report three cases of anidrotic ectodermal dysplasia with an X-linked form. Two cases are sporadic forms, followed up during ten years; the third case is a familial form followed-up through six generations. With their personal cases, the authors insist on the repercussions in the everyday life; they report the signs which must search for an heterozygosis among the females of this families: hypoidrosis, hypodontia, hair shaft abnormalities under polarized light, special look of the face of those females who are alike sometimes wonderfully.

About one homozygote female for haemophilia, authors report circumstances where we can see an haemophilic female: lyonisation, chromosomal abnormalities of X chromosome, and homozygosis. They report the cases of literature.

An experience of three centers of genetic counselling (West France). The authors attempts to explain why in 9 cases the pregnancy was not terminated.

What do we do when one of two monozygotic twins is affected with a severe urinary malformation? - termination of the affected zygote? - termination of the two zygotes as wanted by the parents? - not any intervention? About a personal case, the authors described their experience.

Description of a family who presents two cases of neonatal myotonic dystrophy (Steinert's disease) in two successive generations. The authors summarize the different genetic theories generally advanced; they sum up the antenatal means of diagnostic that is based on the knowledge of linkage of the loci for myotonic dystrophy and Lutheran blood group.

Authors report one family with three cases of myeloblastic acute leukaemia in three generations. In this family, without chromosomal abnormalities (the only one possible laboratory examination), the risk is certainly increased, but it remains, fortunately, low.

The authors propose an original classification of the polydactyly. They opposed: polydactyly "symptom" and polydactyly "disease". Discussion about five personal pedigrees.

A family with X-linked recessive microcephaly is reported. As patients there were found 8 men or boys respectively out of 3 generations, all of them being related by their mentally healthy mothers. Besides microcephaly the patients showed growth retardation and obesity. Some of them, in addition, had various anomalies as inguinal or umbilical hernias, cryptorchism, tapering fingers, contractures, deeply rooted thumbs and club-feet. There were no hints for a metabolic defect or a chromosomal aberration. The dermatoglyphics could be investigated in 5 patients and showed in all of them a shifting of the axial triradius into the distal position t'. Comparing the own findings with case reports on X-linked microcephalies, the above mentioned family was found not to correspond to any of these observations. It is assumed that in this family, a new disease has occurred which until now has not yet been described, so that the X-linked microcephalies seem to be a heterogenous group of disease from the genetic point of view.

The authors report a familial case of exomphalos affecting a mother and her daughter; they discuss the possibility of a dominant transmission.

Authors examined 80 pairs of parents with affected children with spina-bifida. They compared the incidence of spina-bifida occulta in parents and in 211 controls. The conclusion is: there is no increased incidence of spina-bifida occulta in parents of spina-bifida.

Authors remember the interest of the old photographs belonging to the families; the authors show how they can help the diagnosis; they can also help to assert the mode of inheritance; in few cases, they can find some female carriers with clinical signs; at last, infrequently, they prove the presence of the disease in a remote generation: so, they prove that the one case is not sporadic but is a familial case; this fact is very important for the genetic counselling of the females of this family. With some cases of the genetic counselling unit of Rennes, authors explain these various situations.

Prenatal diagnosis of cystic fibrosis is today possible by chemical study of amniotic fluid during the 18th week of pregnancy. We have, among 90 families seen for genetic counseling between 1972 and 1985, estimated the risk of recurrence; it was of 0.25 in 55 cases; between 0.05 and 0.16 in 30 cases, greater than 0.01 in 16 cases. Before suggesting a prenatal diagnosis, it is necessary to take as basis the risk of abortion and the reliability of the method. The first risk is well known, less 0.005, in these young women; reliability can be estimated: almost 0.01 of false wrong negative, and this number is probably overvalued if all technical conditions are perfect. In front of these risks, it seems possible to propose a prenatal diagnosis from a risk of 0.01, the families being informed of all risks. We think so to hearten some families and to make possible for them to live quietly these pregnancies, probably non undertaken without our help.

A collaborative study on 92 Robertsonian translocations is analysed in relation with the methods of ascertainment, the type of rearrangement and potential imbalance of the anomaly. The results are useful in genetic counselling.

The case of a 4 years old boy, hospitalized for an unexplained coma, is reported. He is the first child of a non-consanguin couple. The psychomotor development of this child was considered as normal up to the age of 18 months; then, a delay in language development, behaviour disorders with an important instability interrupted by episodes of somnolence, were observed. This child was treated for psychotic disorders. At the age of 3 and half, he had two episodes of seizures associated with fever. He was hospitalized for a 24 hours coma (4 years old). An hepatomegaly and a dry, brittle hair were then observed. Hyperammonemia was made obvious by a protein tolerance test. The diagnosis of argininosuccinate lyase (ASAL) deficiency was based on the increased levels of ASA in plasma and urine. The deficiency was proved by a fibroblast culture. With protein restriction, hepatomegaly disappeared, hair became normal, the behaviour disorders and the delay in language development was improved. However, some school difficulties persist. This case shows that an hereditary metabolic syndrome can be revealed by psychotic like symptoms in childhood.

Case histories from the pediatric reanimation department (intubated children of 0 to 15) and neonatology of Renne's hospital are reviewed for the years 1987 and 1988. Among 1.555 admissions (486 in reanimation, 1069 in neonatology), 63, that is 4%, concerned the clinical geneticist. The distribution may be done in 32 malformations and genetic syndromes, 8 chromosomal defects, 6 neuro-muscular diseases, 6 metabolic diseases, 3 cystic fibrosis, 3 spina bifida, 5 varied diseases. The advice of the genetic counsellor was requested 8 times for an urgent case, and to arrive at a decision about a reanimation, 7 times before the death of a patient for the management of diagnostic techniques: biopsy, blood or urines sent to a specialized center.

Truncus arteriosus is an uncommon heart malformation; it is not reported that recurrence is high; nevertheless authors report three families with two or more cases; in the third there is a very high consanguinity (two uncle-niece marriages). The authors compare the situation with hypoplastic left heart and think that some cases of truncus arteriosus would have an autosomal recessive inheritance. That is an another argument for suggesting an echocardiographic survey of the pregnancies in these families.

The authors report a case of a family with hereditary compression of peripheral nerves. The disease is traced through five generations. Six members were proved to be affected. 14 patients were examined. The review of the literature and the family studied suggest that the disorder is transmitted by an autosomal dominant gene with variable expressivity.

Description of two monozygotic twin sisters both showing at 6 1/2 months of intrauterine life the existence of a severe form of osteogenesis imperfecta. On this occasion the authors insist on the necessity of X-rays in cases of stillbirths which will enable the physician to give an appropriate genetic advice.

In a Bickers-Adams family followed up for almost 20 years, authors report pregnancies of two propositus' sisters: echographic diagnosis of (normal) girls, of normal or affected boys and selective abortion in a case of dizygotic twin pregnancy with a normal girl and an affected boy.