Using Bansal & Rife's recent study (1962) as a working model, certain two-fold groupings of four palmar main lines and the axial triradii positioning have been proposed on the basis of the writer's unpublished work (1962). Some fairly encouraging penetrance figures suggest to apply the same groupings on twin data, on largest and richer family material drawn from the same Mendelian population, and to use other available methods of penetrance calculus, including one from concordance figures that is under investigation by the author.

A survey conducted at the Rehabilitation Institute of Montreal, covering 250 cases of cerebral palsy, came to include three pairs of identical twins, all discordant as to the disease. Pair I was female, 8 years old; Pair II, male, 6 years old; Pair III, female, 18 years old.

All vere subjected to physiatric, psyschiatric, and psychological tests as well as to tests involving activities of daily living. In each instance, the study was completed by EEG's still and motion pictures. The investigations included psychological and psychiatric evaluation of parents.

Extensive medical, psychological and psychiatric conclusions are drawn.

Since the original description of the Prader-Willi syndrome (PWS) in 1956 [1], and the recognition of the involvement of the proximal region of chromosome 15 in this disorder [2], understanding of the molecular basis of the genetic defect in PWS has progressed rapidly. A set of clinical criteria has been defined [3], although the diagnosis on clinical grounds alone remains difficult in the first year of life. Research has focussed both on improving the diagnostic molecular and cytogenetic tests for PWS and on identifying and defining the functions of genes whose expression is altered in this neurobehavioral disorder. Furthermore, this region is known to be subject to genomic imprinting effects, so that expression of genes involved in PWS is expected to be exclusively from the paternal allele.

A critical step in the definition of the region containing such genes was the identification of a subset of unusual patients affected with either PWS or the Angelman syndrome, which also involves a gene or genes in the proximal region of chromosome 15. These unique patients, who have chromosome 15 translocations or deletions, helped to narrow the critical region to an interval containing less than 500 kb of DNA [4-6] (Fig. 1). As will be discussed, below, regulatory elements exist in this 500 kb region which alter the expression of genes located outside this interval [7, 8].

Les résultats statistiques sont exacts dans la mesure où nous disposons de séries gémellaires MZ et DZ non sélectionnées. Il est nécessaire que cette condition soit réalisée, si l'on veut déterminer la probabilité de manifestation d'une tare.

D'autre part, pour les maladies dont l'âge d'apparition est très variable (diabète sucré, schizophrénie, folie circulaire), un certain nombre de jumeaux sont considérés comme normaux, alors qu'ils n'ont peut-être pas encore atteint l'âge de manifestation. Pour ces cas, nous devons utiliser une méthode correctrice, tenant compte de l'âge. Certaines séries gémellaires de nos statistiques n'ont pas subi cette correction, et de ce fait les valeurs peuvent être plus ou moins faussées.

Il est en outre souvent difficile de différencier l'hérédité polygénique de l'hérédité monofactorielle à pénétrance très incomplète du gène responsable. Penrose (1953) a démontré qu'il est illusoire de vouloir, sur la base des données familiales, trancher en faveur de l'un ou l'autre de ces modes d'hérédité, lorsque la fréquence du trait ou de l'anomalie chez les parents et leurs enfants est moins de dix fois supérieure à la fréquence observée dans l'ensemble de la population.

The experimental cotwin control method by means of 34 MZ pairs, of which only one cotwin of each pair suffered from typhoid disease, offered excellent opportunities to study the after effects of typhoid incidence on the anthropometric, mental and physical traits of individuals. Comparison among 56 MZ pairs reveals that typhoid brings out certain significant changes in these traits.

Increase of intelligence has already been shown, due to increased quantity of RNA. Whether or not typhoid incidence after a period of approximately 7 months influences the rapid synthesis of RNA would be a good field of biochemical investigation of immunogenetical interest.

A total of 59 children from multiple pregnancy, aged from 18 months to 13 years, have all shown a mental development within or above normal limits.

In 18 children there are reasons to suspect the presence of a CNS lesion, although the general mental level is good.

The numerical concordance of intelligence quotients is not typical for MZ and DZ twins. In four cases there were marked qualitative differences despite IQ concordance.

The behavior of twins in their home, preschool, and school environment, is determined by the separate nature of the relationship in which the twins live since birth.

The possibilities of early diagnosis of multiple pregnancy are shown, which helps to prevent and reduce the incidence of premature deliveries.

Almost one century after Galton's first scientific formulation of the Twin Method, based on the comparison of MZ and DZ twin series, not only twin studies play a fundamental role and the Interzygotic Test is widely applied in human and especially medical genetic research, but new methods have also been worked out, such as the Azygotic Test and the Twin Clinical Method.

Moreover, the study of twins has more recently led to new insights into the study of biological times, with the development of the modern branch of Chronogenetics.

Following a suggestion of Gedda and Bérard-Magistretti, intra-pair differences between MZ twins in fusional reserves were compared with differences in psychological variables. While the strong relationship between twin leadership and FR which these workers found in twin children was not confirmed in the present small sample of 14 adult pairs, the twin with the higher FR tended to be the more introverted, the more intelligent and the one who volunteered for the investigation. He also tended to be the taller and the first born.

Further studies, including the temporal reliability of scores of fusional convergence, are required before the value of this characteristic as a psychological criterion can be established.

A method for the preliminary analysis of a maximal number of urinary amino acids has been devised, which is based on preliminary ‘purification’ and desalting of each specimen prior to its subjection to two-dimensional paper chromatography. Aliquots of processed and concentrated specimens are standardized to quantities of alpha-amino acid nitrogen as determined colorimetrically.

Densitometric index values were analyzed for sex differences and for intrapair differences comparing genetically related and unrelated pairs. Significant sex differences were observed for five substances. Significant deviations between intrapair differences of genetically-related and control pairs were observed for ten substances. The results are compatible with the hypothesis that quantitative differences in the respective excretions involve genetic factors.

Current antenatal technologies have improved the obstetrician's ability to assess fetal well-being as well as to diagnose fetal compromise. These technologies have given rise to very difficult ethical issues in the management of compromised twin pregnancies: for example, a choice must be made between putting a healthy twin at risk due to preterm delivery for the sake of a compromised cotwin or of allowing the compromised twin to die in order to buy time for the healthy twin. Though each case is unique, good medical practice requires a standard of care by which consistent patient management can be proposed. In the pluralistic environment of Northwestern Memorial Hospital, our staff has favored a standard of care based on patient autonomy. This approach demands: 1) a practitioner who offers a thorough explanation of the diagnosis and possible treatment approaches; 2) time for the patient and her partner to assimilate this information and test treatment options against their personal value system; 3) a third, but disinterested, party to facilitate patient understanding and value clarification; 4) a practitioner either willing to support the patient's decisions or refer her to another practitioner who will.

The Authors refer the results of the genetical research on 91 probands with cancer of the corpus uteri (unselected sample of the 144 collected cases). In comparison with a suitable control material significant higher familial incidences result in females for uterine cancers and in males and females together for cancers of all sites.

Present concepts on the etiology of childhood tumours are reviewed. The differences in clinical manifestations of the hereditary and nonhereditary types are illustrated with data on retinoblastoma and on nephroblastoma. Notwithstanding these differences it is most likely that the fundamental etiologic process is the same in both and that it consists in successive mutational events. The possible consequences of the association of retinoblastoma with a deletion of chromosome 13 in some cases are discussed. Several explanations for the association of Wilms' tumour and aniridia are also discussed.

To search for evidence of genetic variation among the aminoacyl-tRNA synthetases, a semi-automated assay procedure employing a Technicon Auto Analyzer was used to measure erythrocyte arginine-tRNA synthetase activity in samples obtained from normal human twins of various ages. Variation in enzyme activity within the older DZ twins was five times that of the MZ twins suggesting the existence of genetically determined variation in enzyme activity. Higher enzyme activity was observed in newborn DZ unlike-sexed twins than in like-sexed twins of either zygosity. Possible explanations for this observation are discussed.

The acute form of twin-to-twin transfusion syndrome is caused by rapid transfer of blood from one of the twins to another via placental anastomoses. Usually, this only occurs during the second stage of labour as a result of a sudden relative rise of blood pressure in one of the fetal circulations. This can result in the sudden intrauterine death of a fetus (or both, as in our case). Currently, there is no reliable means of identifying such an at-risk pregnancy by means of ultrasound antenatally. We would classify this as TTTS Type III.

Fasting blood glucose and serum immunoreactive insulin (IRI) and the responses of blood glucose and serum IRI to peroral glucose challenge were investigated in middle-aged normoglycemic male twins of 17 monozygotic (MZ) and 18 dizygotic (DZ) pairs recruited from the Finnish Twin Cohort Study. Also, the role of obesity and diet in the regulation of glucose and insulin metabolism was estimated. The fasting and 2 hr postprandial (PP) glucose showed higher pairwise correlations in MZ (r =0.78 and 0.56) than DZ (r = 0.08 and −0.05) pairs whereas fasting and PP insulin levels and the areas under the PP glucose and insulin curves were weakly and similarly correlated in MZ and DZ twins. The pairwise correlations of the 1/2 hr and 1 hr, but not the fasting and 2 hr insulin/glucose ratios, were somewhat higher in MZ (R = 0.51 and 0.53) than DZ (r = = 0.28 and 0.30) pairs. In MZ twins, the intrapair differences in the body mass index were significantly correlated with those in the fasting and 2 hr PP glucose and insulin levels and those in the fasting and 1/2 hr insulin/glucose ratios (r from 0.47 to 0.76). Also, the intrapair differences in the dietary fat calories were correlated positively, but those in the calories derived from carbohydrates negatively, with the intrapair differences in several parameters of the glucose and insulin metabolism. These data suggest that the environmental contribution to the regulation of glucose and insulin metabolism in subjects within the normoglycemic range may be quite strong. Of the environmental factors studied, obesity and dietary fat consumption seem to have powerful regulatory roles, particularly in the response of insulin to the glucose load.

M, N, S and P factors have been studied in a selected sample of the Rome population. A comparison of the findings with the sofar available data shows that the distribution of the examined factors is not influenced by the variations of the geographic position in Italy. The frequency of the « s » factor also appears to be greatly higher than that of « S ».

The application of multiway contingency table analysis to the multivariate analysis of concordance ratios in twin studies is developed. The approach is illustrated by data on smoking and alcohol use in Finland and Sweden. This approach can enable the assessment of the effect of other variables on the concordance ratio and thus allow estimates of genetic effects on the trait under study. Hypotheses on relationships between genetic effects and other variables can be tested. After hypothesis testing, model fitting of the best hypothesis can be carried out.