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

Partial trisomy for the long arm of chromosome 15 was detected in a 21-year-old girl with severe growth and mental retardation. A balanced reciprocal translocation - t(7;15)(q35;q14) - is present in the mother.

The juvenile type of adrenoleukodystrophy is a X linked genetic disorder involving the central nervous system and the adrenal cortex. It is associated with an abnormal metabolism of saturated very long chain fatty acids. The basic defect remains unknown and there is presently no effective treatment. The authors report a familial observation which illustrates the efficacy of the techniques of identification of heterozygote females carriers and of prenatal diagnosis from trophoblast biopsy.

Acrokerato-elastoidosis described by Costa is characterized by numerous little keratotic points and translucent horny wheals on the dorsal aspect of hands and (or) feet. The ultrastructural study shows lesions of the elastic tissue which is very rarefied with an abnormal structure, but also demonstrates alterations of the fibroblasts that contain dense granules at the periphery of their cytoplasm without elastic extracellular fibers, suggesting a trouble in the secretion or the excretion of the elastic material.

The existence in a new-born child of post-axial polydactyly, associated with an abdominal tumor due to hydrocolpos, because of a low vaginal atresia, and with congenital heart-disease, recalls the diagnosis of the McKusick-Kaufman syndrome. This syndrome must be differentiated from the Ellis-Van Creveld syndrome, which also includes polydactyly and congenital heart disease, associated with a "chondrodysplasis" and an "ectodermodysplasia".

Chondrodysplasia punctata has very diverse clinical and radiological features. Its diagnosis may be suggested as early as in the neonatal period in front of an abnormal facial appearance, sometimes associated with bone and vertebrae defects. Radiological exams will assert it. Its subsequent course depends on the accompanying visceral abnormalities. Genetics advice is closely related to these. Ultrasonography is the only actual possibility of prenatal diagnosis. However our attitude must be guided by the clinical course (of the disease) of the initial case in the sibship.

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

Adrenoleucodystrophy (ALD) is an X-linked hereditary disease concerning very long chain fatty acid (VLCFA) metabolism. It affects cerebral white matter and adrenal cortex. In the adult form, (adrenomyeloneuropathy) we also find hypogonadism. The enzymatic anomaly, yet unknown, takes place in the peroxisome. The illness is diagnosed by plasma VLCFA amount determination. We actually have no efficient treatment. Prenatal diagnosis is possible, using both biochemical assays and linkage analysis to a DNA probe.

Cases of two newborns with acute lymphoblastic leukemia (ALL) L2 type, are reported. In each case, some chromosomal abnormalities can be found. In the first case, a translocation t (4;11) is noticed. It has to be compared with already published patients' cases and so the non randomly occuring character of those alterations in ALL and poor pronostic factor can be confirmed. In the second observation, a complex translocation t (5;6;X) never described before in literature, was observed. Chromosomal findings in ALL are not only a help to diagnosis but, by cytogenetic data, are also a help to accurate prognosis and adequate treatment.

The authors report two cases of infant encephalopathies with psychomotor retardation. The cerebrospinal fluid, the electroretinogram, the electromyogram and the motor conduction velocity are normal. The neuromuscular cutaneous conjunctival biopsies are normal. No biochemical abnormalities are found. The electroencephalogram presents continuous high voltage fast rhythms (250-400 microV) with reduced or absent evoked responses. Early infantile neuroaxonal dystrophy and lissencephaly are suggested.

Incidence of cystic fibrosis has been estimated in three adjacent geographic areas of Brittany: North Finistere, South Finistere and Morbihan. This incidence is respectively 6.0 x 10(-4), 4.8 x 10(-4), 2.9 x 10(-4) in these three areas. A significant difference between North Finistere and Morbihan was found. Without proofs in favor of natural selection, genetic drift seems to be a possible explanation of this variation. Moreover, as in other studies, a genetic heterogeneity of the disease was not shown.

Prenatal diagnosis: The authors present a personal case of triose-phosphate-isomerase deficiency. Clinically the deficiency associates a constitutional non spherocytic anemia, paroxystic and precocius, and neuromuscular symptoms (axial hypotonia and limb palsies). A diaphragmatic paralysis may complicate the syndrome. Infections are frequent. Survival rarely goes beyond 5 years of age. Biochemical exams show the ubiquity of the deficiency. The physiopathology remains obscure. The TPI deficiency is heritable (autosomal recessive transmission). The gene has been mapped on the short arm of the chromosome 12. Prenatal diagnosis is possible.

The existence of double autosomal trisomy is exceptional in a newborn child: --Down syndrome and trisomy 18. --Down syndrome and trisomy 13. On the other hand, the association of an autosomal trisomy, generally Down syndrome with gonosomal trisomy, is less rare with an extra X (triplo X, Klinefelter) or an extra Y. The association of Down syndrome with Turner XO syndrome (autosomal gonosomal association) doesn't insert in the subject, and has been described only once in the literature.

A new case of partial monosomy of the short arm of chromosome 12 is described in a 17-year-old girl and compared with other observations reported in the literature. The breakpoints were localized to region 12p11----12p.12.1. Qualitative and quantitative activity of LDHB allowed a precise assignment of the structural gene to sub-band 12p12.2.

A child with the 49 XXXXY syndrome is presented. Diagnosis was possible early in life, because of craniofacial anomalies and congenital cardiac malformations. The main symptoms are growth retardation, craniofacial abnormalities, hypogonadism, frequent bone lesions and severe mental retardation.

In a newborn, the presence of an abdominal tumor due to hydrocolpos resulting from vaginal atresia, with polydactyly and a congenital heart disease suggest the diagnosis of McKusick-Kaufman syndrome. This syndrome is different from the Ellis Van Creveld syndrome, which also includes polydactyly and congenital heart disease, associated with "chondrodysplasia' and "ectodermodysplasia'.

We have seen two cases of diprosopy associated with anencephaly in Brittany between 1975 and 1984. Diprosopy is a partial or total duplication of the face. It consists of the phenomenon of late division in the embryo of the cephalic portion of the neural plate between the 16th and the 18th days. This gives rise to an incomplete type of monozygotic twinning or a conjoint twin. There are several different forms of the organs that are duplicated. We have seen a case of diprosopos distomos dirhinos diophthalmos and a case of disprosopos distomos dirhinos triophthalmos. These two cases were associated with anencephaly, the second also having a spina bifida and a diaphragmatic hernia. One can explain the incidence of anencephalies in cases of diprosopies by the desturbance created by the latter on the embryological events that succeed it. The delay in nerve formation makes it impossible for the neural tube to close completely, and this is why sometimes the anencephaly is associated with spina bifida. In more general terms one can postulate that all conjoint twins that are, of course, monozygotic and monochorial can interfere with early enbryological development and increase the risks of failure of the neural tube to close.

About a familial observation of PK deficiency, the authors emphasize the important clinical and biochemical heterogeneity. Interest of isotopic explorations in the therapeutic decision of splenectomy.