The frequency of the developmental dysfunction and specific learning disabilities were assessed in the retrospective study in the group of 56 school-aged twins. The relationships between genetic, perinatal and social factors and learning disability were also determined. It was found that 12.5% of twins had learning disabilities. The most common neurodevelopmental dysfunction were language disorders, poor graphomotor fluency and poor fine motor dexterity. It was also found that educational difficulty were associated with prematurity, low Apgar scores, neonatal complications and familial predisposition.

Nine family cases of diabetes are genetically interpreted on account of a polygenic model of inheritance, with each allele being characterized by a different probability of chronological stability of the normal information. This model provides a satisfactory interpretation of the clinical and subclinical variability of diabetes — which the diallelic model is unable to do — and has on the polygenic model the advantage of a higher fitness to a case of discontinuous variability, such as diabetes. Both pedigrees characterized by apparent recessive inheritance and those characterized by apparent dominant one may equally be interpreted on account of the polyallelic model.

The origin of polyallelism is attributed to the hereditary variability of the gene's temporal unit (chronon). As a result, the phenomenon of “anticipation” may also be interpreted, and the one-origin clinical and sub-clinical variability of diabetes be demonstrated.

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groupings of four palmar main lines and the axial triradii positioning have been proposed on the basis of the writer's unpublished work (1962).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.

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.

The Twin Clinical Method (Gedda, 1963) has been applied to the study of dental pathology. Four cases of MZ female twin pairs have been studied, concordantly affected by dental agenesis (case I), mirror-imaging dental agenesis (case II), diastema (case III), and dental caries and enamel dystrophy (case IV). The test has also been applied, and for the first time, to a set of MZ female triplets, concordantly affected by dental caries and malposition.

In all the above cases, the test has permitted to reject hypothesis of a concordance being due to chance, while postulating the existence of a causality.

The latter is ascribed to the common heredity characterizing MZ cotwins.

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.

Campimetric pictures in several cases of chiasmal syndrome are presented. Comparison between white light and laser visual field data shows that earlier and more precise evidence of visual field defects is obtained with the latter method.

There are a lot of publications about fetal arrhythmia in singletons, but up to now there are no published data about fetal arrhythmia in multiple pregnancies. In the present study a case history of fetal and neonatal arrhythmia in one of twins from two mothers treated with betamimetic agents due to imminent preterm labor is reported and discussed. A first case with fetal bradycardia due to complete A-V block had congenital cordis abnormalities (VSD and PFO). The second case with prenatal detected extrasystoles had normal heart anatomy. Digoxin was administered to the mother, in the aim to treat fetal arrhythmia without success, because the baby had postnatal bradycardia. After hospitalisation in Cardiology Department the described cases were successfully treated. In both cases the second twins were without neonatal arrhythmia and with no structural heart abnormalities. We summarise that in situation of detection fetal arrhythmia the complexity of the problems experienced may warrant early referral to a tertiary centre where the overall management of the mother, fetus and neonate, may be undertaken.

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.

Myopia is the world's most common cause of defective vision. The role of controlled accommodation on the progress of myopia is unsettled. This cotwin control study is designed to provide a careful appraisal of the effectiveness of a clinically acceptable method of controlling accommodation. There are no previous reports of similar prospective studies among MZ twins. Expansion of such studies would be aided by collaboration among interested investigators.

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 ».

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.

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.

A pair of female mongoloid twins was studied when they were ten years old and, again, some thirty years later. A careful comparison was made of the similarities and differences between them in features or traits which have proved to be useful in determining the zygosity of like-sexed twins.

Though some of these characters can be, and frequently are, considerably modified in the presence of mongolism and so lose part of their value for that purpose, the differences noted in these twins, both as children and as middle-aged adults, are thought to outweigh their similarities and so warrant the conclusion that they are, indeed, dizygotic.

Drawing is an excellent means of investigating the personality of identical twins. It gives an overt expression of the difficulty of arriving at the consciouness of the self, so frequently found with these persons. Some of this article's drawings illustrate this fact and show the persistence of duality and confusion.

The strength of the tie to the other twin, the wish for indépendance from him, the dominance of one subject in the pair are also made manifest.

Furthermore, the existence of some affective reactions toward the family and the frequent opposition between the types of behavior, found in the two members of a same pair toward the auter world, are shown.

A certain amount of material is provided for studying the heredity of fissures of the iris, and it seems that such a heredity is probably not of monohybrid nature. The relationship between fissures and pigmentation of the iris has been confirmed and noted also by earlier researches. This connection may be explained by the fact that fissures of the iris-appearing even earlier, during embriological development—leave fewer chromatophores in the stratum limitans anterior for the formation of pigment. It thus follows that the colour of the iris, which is determined by comparing it with table of colours of the eye, would not be of monohybrid heredity. It is doubtful even when both colour and structure of the iris are contemporaneously studied in order to realise a polysymptomatic resemblance—as for the diagnosis of monovular twins of the diagnostic of paternity—since the logical basis for establishing a polysymptomatic comparison of resemblance is, in fact, given by the independance of partial signs connected one with another. This goes for all cases, whether or no statistical methods are used for the critical examination of such researches, such as, for example, Essen-Möller's formula (3,4) (Wichmann 22, 23).

The typical picture of mongolism has been observed in both members of a proved monozygotic twin-pair, aged 15. There is no indication in the family history of any hereditary predisposition, and both, the pregnancy and the birth were quite normal. The author reviews all cases previously reported, and expresses the opinion that mongolism is due to some phenomenon occurring during the germinating period, that is to say during the initial stages of development of the egg.