Since the MNS blood group system does not exhaust the total degrees of freedom under the Wright's equilibrium law, it was felt that the peculiar problems facing the detection of F (the fixation coefficient of Wright's model) from ABO blood group data may not be totally relevant to the MNS system. To verify this, a short discussion on the detection of F from MNS blood group data is given here.

Using therapeutic intervention, the psychological and behavioural factors in the development of language retardation in two pairs of 4-year-old MZ twins have been examined. Although some factors are common to those found in singletons with language retardation, the factors peculiar to the twin situation are highlighted.

The A. reports some fundamental biological proceedings in a preventive treatment of hereditary diseases.

She divides prophylaxis in idiotypic and phenotypic and after having examined the different aspects of the problem, concludes that a positive eugenetica is possible by acting on environment disposing or exposing conditions. The A. finally indicates how studies should be carried on in order to attain this object.

The morphological examination of the afterbirth of the Danzig quintuplets showed that it was composed of five fused placentas forming one single placenta, of extraplacental fetal membranes forming five separate fetal amniotic sacs and five umbilical cords. The structure of the placentas was very similar and no focal pathological changes were found in their texture. From a morphological point of view all separating membranes speak in favour of a quintovular pregnancy.

Macroscopic examination of the placenta and histological examination of the membranous partition between amniotic sacs was peformed in approximately 1400 twin maternities in Ibadan, Nigeria.

Monochorionic placentation is mainly characterised by two layers (as opposed to four in the dichorionic one) in the dividing septum between the two amniotic sacs, as well as by the absence of a membranous ridge of tissues at the base of the septum, that is instead present in the dichorionic one.

Monochorial twins appear to be invariably MZ, whereas dichorial twins may be either MZ or DZ. In the present study the chance of being DZ was 95% in the case of single and of 99% in the case of double dichorionic placentation.

New researches have made it evident that besides the two normal Hb, the adult one (a) and the phoetal (f), there are other pathologic Hb: c, e, s, d, g, h, i.

These Hb, excepting the h, are present in the hetherozygote on every healthy person and in the homozygote, excepting the g Hb, determine chronic hemolitic anemia.

The f Hb, or a very similar Hb, is present in the Thalassemia minor and major, in some homozygote cases of abnormal Hb, in the interreaction between two different genes of these Hb, or between one of these genes with the one of Thalassemia.

We may retain that the genes a, c, s, d, e, g, i, form an allelomorphic series. The gene Th is not a part of this series.

Since in the homozygotes ss, cc (in absence of the gene a) the quantity of abnormal Hb does not always reach the same percentage, we may logically retain that the different quantity of abnormal Hb possessed by the s and c hetherozygotes depends from the different synthetic capacity of the genes of the two abnormal Hb. The appareance of f Hb may be the expression of a phenomenon of physiopatological compensation, which occurs when Hb a formation is prevented.

Considering the development of the twin method the Authors deem it necessary to review the various systems of analysis presently used. They therefore design a method by which the twin material may be used even when zygosity is unknown. The Authors give this method the name of Azygotic Twin Test (T.G.A.), explain it theoretically and also give a practical example of analysis.

The Authors plan to make - new studies on the subject, in order to show further possible developments of this method.

Fifteen hundred palmar prints of normal persons and patients suffering from various diseases were studied and classified as to dermal ridge configurations at the base of digit IV, after the exclusion of main line C courses with endings at one of the palmar marginal regions. This classification scheme, based on the three classical reduction forms of line C (O,X(8),x), resulted in the differentiation of three main groups, A, B, and C. Within these main groups, pattern types with strong similarity were combined to subgroups allowing an easier documentation. Twin and family data were used to test whether the described pattern types, besides the classical abortive states O,X and x of line C (called special and intermediate forms), are heritable and for which of them a remarkable reduction tendency could be established. The results allow us to confirm the main grouping and the assumed reduction tendency of the special forms of group A.

Three case reports are presented concerning 1) Albino MZ female twins, 2) Raynaud's syndrome in MZ female twins, and 3) Pseudohermaphroditism in MZ male twins.

The Authors have analyzed the data concerning length of gestation and neonatal weigth and length measurements in 2,440 living twin pairs (from the files of the Mendel Institute), in order to verify the frequent assumption that all twins should be considered as prematures and, as such, affected by congenital debility.

Comparing their findings with the standard values for prematures, they reach the conclusion that the majority of twins who have survived the perinatal period were not prematures. Furthermore, the less developed among such twins differ from single-born prematures by reason of their subsequent normal auxologic development, whereby the Authors propose that they should rather be considered as “premature-like”.

This study showed that biological handicap with many complications at birth was much more recognized in the second-born than in the first-born twins. One of the most prominent intrapair differences was, for example, the weight at birth. However, intrapair differences, which were observed also in other physical measurements, diminished gradually with age. Moreover, as for intellectual ability, which was represented by the scores of the entrance examination test or standard achievement test, no remarkable influences due to handicap of the second-born were identified. Thus, it was concluded that the biological handicap seen in the second-born twin at birth did not give any significant effect on later development.

The Author give a detailed description of a rare observation of hypophyseal dwarfism in a monozygous twin.

The patient showed the classic symptoms of dwarfism and infantilism which have produced a discordance in some characters; important and useful are the results obtained from clinical and laboratory data. They have confirmed the diagnosis of zygotism.

Soixante-douze paires de jumeaux de même sexe, âgés de 6 à 22 ans, ont été examinées à Bruxelles par l'équipe du Prof. Twiesselmann. Ils ont été séparés en deux groupes, 35 paires de concordants et 37 paires de discordants pour au moins un des neuf sérums des groupes ABO, MN et Rh. Aucun élément subjectif n'est donc intervenu dans cette ségrégation basée sur des facteurs dont le mode de transmission est connu. Nous n'avons fait aucun essai de diagnostic de zygotie basé sur la plus ou moins grande similitude de caractères morphologiques, de façon à rester dans un domaine absolument objectif. Le groupe des discordants est évidemment composé uniquement de jumeaux DZ. Celui des concordants comprend tous les MZ plus vraisemblablement quelques paires de DZ.

Pour l'étude des dermatoglyphes, nous avons retenu trois caractères: le nombre total de triradius digitaux (pattern intensity index), l'indice des lignes principales (main line index) et le nombre de crêtes entre les triradius interdigitaux a et b (a-b ridge-count).

Nous avons d'abord étudié les corrélations entre jumeaux d'une même paire (Fig. 1). Dans le groupe des discordants sérologiques, les intervalles de confiance des coefficients de corrélation englobent la valeur théorique de 0.5. Chez les concordants, ils approchent de l'unité et les coefficients de corrélation vont de 0.83 à 0.85. Aucun de ces intervalles de confiance ne se chevauche, malgré leur étalement dû au petit nombre de sujets.

In 1969 children of a multiple birth in the GDR made up 1.9% of livebirths and 15.3% of early neonatal deaths. The early neonatal mortality rate of children from a multiple birth was 95.7‰, that of all live-births 12.4‰. The cause was the low birth weight of children from a multiple birth (56.2% vs. 5.8% of all livebirths). Their low birth weight is the result of a hypotrophic development caused by malnutrition. The loss of children from a multiple birth (stillbirths, early neonatal and postneonatal deaths) was 143‰. International experience has shown that such heavy losses can be largely prevented by bed rest of the woman with a multiple pregnancy. We therefore strongly recommend early diagnosis and early in-patient care of women with multiple pregnancy.

Blood and saliva samples of 122 like-sexed twin pairs (65 MZ and 57 DZ) living in Chandigarh (India) were analyzed for ABH polymorphism. The results indicated that ABH secretions were independent of ABO blood groups though there was an indication of higher incidence of non-secretors among ‘O’ blood group twin individuals. No significant differences were observed between twins and singletons in secretor gene frequency estimates. The quantitative data revealed that mean titre scores for H substances were lower than that for A and B substances. F test contrasting intra-pair variance between zygosities for ABH quantitative secretions was highly significant indicating stronger genetic component of variation. The results suggested that quantitative assay of ABH secretions would be a better indicator for zygosity determination than mere qualitative differentiation.

This study is based on pedigrees of 287 patients with Rheumatic Fever, which are compared with pedigrees of 300 controls: 11,7 per cent of all relatives in the first group had rheumatic fever, compared to 2,2 per cent of all relatives in the control group.

An hereditary predisposition to rheumatic fever is definitevely to be admitted.

This predisposition is due to the presence of a principal autosomal dominant gene with reduced penetrance and variable expressivity.

It seems to have no genetic relationship to the diathesis of allergic diseases and the diathesi of degenerative connective tissue disorders mesenchymotic diathesis.

1. Data relating to hypertrichosis of the ear rim, lobe, tragus and antitragus in the Pahira are presented.

2. It has been indicated that (a) hypertrichosis of the rim is associated with that of the lobe, tragus and antitragus, and both may be controlled by the same genotype; (b) it may not be a characteristic of the Mediterranean race alone; and (c) its use as an “anthropological marker” is of limited value.

The clinical findings in a group of syndromes in which tapetoretinal degenerations are associated with systemic lipid disorders are described. This group includes abetalipoproteinemia (the syndrome of Bassen and Kornzweig), Refsum's syndrome, Neuronal Ceroid Lipofuscinosis, and Cockayne's syndrome. AII four are transmitted by single autosomal recessive genes. The pathological findings are discussed. If diagnosed early enough, abetalipoproteinemia should be treated by administration of vitamin A, and Refsum's syndrome by restriction of intake of phytanic acid and phytol.