We report on the observation of six cases in a family of eight, all under 30, in whom the diagnosis was obtained at first hand by rectosigmoidoscopy. This procedure appears sufficient as the number of polyps tends to decrease with increasing distance from the anal margin. The recent finding of abnormalities of chromosome 5 (long arm) permits the identification of carriers of this genotype by simple blood examination (DNA probe), thus greatly enhancing the possibilities of screening for the disease. Each of our cases was managed with subtotal colectomy and ileorectal anastomosis. Preservation of the rectum was preferred to other techniques as all subjects were young, mildly affected and with good motivation for twice-yearly endoscopic follow-up. The surgical technique appears simple and quite safe with satisfactory functional results and easy feasibility of endoscopic surveillance.

From their own experience, the authors grapple with the difficulties of the genetic counselling in the tuberous sclerosis. They dwell on the necessity of undertaking a very full assessment in the parents of the apparently isolated cases. It includes skin examination, fundoscopy, cranial CT scanning, renal imaging and echocardiography. After these investigations which may need to be done to make or to exclude the diagnosis, it will be possible to quantify new mutations. Nevertheless the exceptional description of pedigrees with incomplete penetrance cannot be forgotten for the genetic counselling. It is likely however that most of these problems will not be resolved until accurate genetic markers are obtained.

Couple or individual reaction after genetic counselling in case of Recklinghausen disease seams us to be very different according to the patients and for a patient according to the moment of counseling. We illustrate this observations with two characteristic examples.

The authors describe a tunisian family including ten patients with neurofibromatosis. Four case reports present dental anomalies (amelogenesis imperfecta) and three have myopia. The authors believe there is no clinical or genetical relation between neurofibromatosis and this dental dystrophia; but myopia may be a clinical expression of Recklinghausen disease.

Referring to a retrospective study of 53 families affected with neurofibromatosis and seen in genetic consultation from January 1977 to September 1987, the authors emphasize the difficulties of genetic counselling in this disease due to its variable expressivity with unforeseeable natural evolution and to the difficulty in detecting minor forms without biological markers. These results confirm previous studies (Carey 1979, Riccardi 1981): About half the cases are relevant to a neomutation and in these sporadic cases, the average paternal age is significantly increased (36.7 years). In familial cases, an intrafamilial variable expressivity is noted in 63.3% of families and no maternal effect is found. The penetrance of the disease, calculated from the familial cases, is estimated to 97% which confirmed the anterior data. The severe forms rate (grades III and IV) is about the same for familial cases, than in previous publications, but is higher for sporadic cases than the proportion described by Riccardi (25 to 30%) probably because of an ascertainment bias. Finally, If the risk for the offspring of an affected patient can be estimated at 1/2, however it is impossible to predict the severity of the disease. Before concluding to a neomutation (1st child of a couple) or to an absence of genetic risk (non affected person related to a familial case), a minor form must be searched by a careful physical examination, although the recent localization of the gene allows us to think of molecular biology for familial studies in a near future.

Since several decades, clinical reports about neurofibromatosis are overwhelming general practitioners, neurologists and other specialists. Since some years cellular biology (specially experimental studies on the neural crest) and molecular genetics light up somewhat the contrast between innumerable phenotypes and the rare punctual mutations which are at the source of the disease. The author reviews the different theories which are attempting to explain the process of malignant transformation in these kinds of diseases (role of eventual oncogenes and recent experiment types of Hinrichs in transgenic mice).

Among the group of hereditary histodysplasia, Bourneville's tuberous sclerosis demonstrate original and important place. Its clinical and histopathological polymorphism make more difficult the diagnosis because many symptoms are non specific and/or appeared at different age of life. The variability of the expression and of the penetrance are a very serious unpeachement for the genetic counselling. A recent reevaluation of several series of case reports seems to demonstrate that the frequency of new mutations has been probably surestimated. The gene location in 9q3-4 is quite certain and will induce soon the possibility of a more efficient prenatal diagnosis. The gene action mechanism at the embryonic development is probably correlated with the "oncogene character" of the specific mutation.

A large cardiac rhabdomyoma was discovered before delivery in a neonate, whose outcome was fatal. The baby and her mother had both cutaneous lesions suggestive of tuberous sclerosis, and the mother's sister had died from Von Hippel Lindau disease. The association of a cardiac rhabdomyoma and a tuberous sclerosis in the same patient is not uncommon, but the existence of Von Hippel Lindau disease in a member of the same family seems to be exceptional.

Chronic myelocytic leukaemia is a myeloproliferative syndrome with two highly specific characteristics: it has a cytogenetic clonal marker known as Philadelphia chromosome and a molecular marker in the form of bcr-abl rearrangement, and it progresses in two phases: a chronic phase followed by an acute terminal phase of blastic transformation. The fatal outcome of this blood disease can only be checked if we possess one or several treatments providing a complete and stable clinical, haematological and cytogenetic remission. Such a course is seldom observed. The conventional treatment of the chronic phase consists of single drug chemotherapeutic regimens which have succeeded in increasing the patients' median survival but do not prevent blastic transformation which is beyond therapeutic resources. In some cases multiple drug chemotherapy, and notably bone marrow transplantation, may result in disappearance of the Philadelphia chromosome and arrest of the natural course of the disease. Interferon is a new treatment which eradicates the Philadelphia chromosome and offers hopes of complete and prolonged, if not permanent, remissions. The present experience, although limited, suggests that alpha-interferons are effective. Judging from the available data, it is very likely that the future treatment of myelocytic leukaemia will consist of chemotherapy combined with interferon(s) with or without bone marrow transplantation.