The simultaneous analysis of means and covariance structures is applied to longitudinal twin data. Body weight was measured on six occasions in a sample of young female MZ and DZ twins. When average body weight at the first measurement occasion, as well as the increments in weight at later occasions, are specified in the genetic part of the model that also adequately explains the covariance structure, a good fit is obtained. In this application the increase in body weight at each occasion is weighted by the square root of the genetic variance innovation terms that represent the new genetic variance entering into the process.

No significant difference has been found in either stroke volume or cardiac output between twin pregnancies and singleton pregnancies. Cardiac output is less in preeclamptic twin pregnancies.

Record linkage of the Finnish Twin Cohort Study with the Hospital Discharge Registry and with the Registry of Rights to Free Medication kept by the Social Insurance Institution gave following numbers of twin pairs with an ophthalmic disease (one or both members of the pair had the disease) in each disease category:98 with glaucoma simplex (5 concordant pairs), 38 with capsular glaucoma (no concordant pairs), 58 with iritis (no concordant pairs) and 149 with strabismus (2 concordant pairs).

The number of concordant pairs in each disease category was small, except for glaucoma simplex in which concordant pairs could be broken down by zygosity. The ratio of observed to expected (based on association by chance) was 6.96 for MZ and 1.74 for DZ pairs. This result suggests that genetic factors play some role in the variability of prevalence of simple glaucoma. Main etiologic factors are stili to be found in the environment. Data on occurrence of other diseases of ophtalmologic importance is presented.

Francis Galton was born on 16th February 1822 (the same year as Mendel). His mother Violetta (1783-1874) was the daughter of Dr. Erasmus Darwin (1731-1802), a medical practitioner in Derby who had scientific interests, particularly in plants, and produced various mechanical inventions. He was also grandfather to Charles Darwin. Galton's father, Samuel Tertius Galton (1783-1844), was a Birmingham banker but possessed a number of scientific instruments. His father (Francis Galton's grandfather), Samuel Galton (1735-1832), also had scientific interests, including colour vision, and was elected a Fellow of the Royal Society.

Francis Galton became a medical student in Birmingham in 1838, subsequently attending King's College London, Cambridge and St. George's Hospital. However, he gave up his medical studies in 1844 after the death of his father [5,17]. Later he travelled in Egypt and South Africa about which he wrote various articles and books, including “The Art of Travel” (1855) [6] of which a total of eight editions were published. His scientific work from these expeditions won him his first medal, the gold medal of the Royal Geographical Society awarded in 1853. Subsequently he wrote further on scientific matters, mainly concerning geography, travel and meteorology. He worked on stereoscopic maps and problems associated with wind currents and sailing ships and introduced the word “anticyclone”. He was elected a Fellow of the Royal Society in 1856 and later to the Council of the Royal Geographical Society, becoming Secretary of the British Association for the Advancement of Science in 1863 [4,19].

In a family 5 females belonging to 3 generations were found with following malformations: Syndactyly (webbed up to the nails), oligodactyly, tendency towards duplication of digits, and brachydactyly. The intrafamiliar variability was not considerable with exception of an probandus having with 5 digits (with duplication on one digit). On the base of ontogeny the question is discussed if the disturbing factor concerning the palm of hand or concerning the squeleton is prevalent. In this family the two dispositions are probably combined. In bibliography a pedrigree with this combination of multiple malformations was not found.

Il glutatione è un tripeptide solforato che trova la sua specifica funzione quale sistema ossido-riduttivo a servizio della respirazione tissulare anaerobia, grazie appunto alla sua doppia presentazione nelle fasi ridotta (GSH) e ossidata (GSSG), che costituiscono, completandosi, il « sistema glutationemico ». Esso è presente nel protoplasma delle cellule viventi dei tessuti e del sangue.

Il fenomeno dell'isoglutationemia gemellare fu rilevato da uno di noi (Gedda, 1943) in una coppia di gemelli MZ, in cui il dosaggio del glutatione ematico dimostrò un'esatta corrispondenza nei due individui; i dosaggi eseguiti su di una coppia qualunque di individui non gemelli non dettero mai cifre identiche.

Altre ricerche gemellari (Gedda e Guarino, 1943, 1945; Gedda e Benigni, 1947), effettuate oltre che sull'uomo anche sul coniglio, dimostrarono che vi erano alcuni casi di discordanza glutationemica (anisoglutationemia), che però nei casi di coppie MZ era soltanto transitoria, e cioè si trasformava, in successive analisi a distanza di tempo, in una isoglutationemia. In un ristretto numero di coppie DZ Pisoglutationemia non poté mai essere dimostrata.

Preterm deliveries in singleton pregnancies have been shown to be associated with decreased rate of growth in utero. A total of 113 sets of twins were scanned serially at fortnightly intervals to establish fetal growth. There was no significant difference in the growth pattern in twins delivered before 37 weeks compared to those delivered after this time.

Among the postulates of the twin method the Author describes especially the fundamental one of comparability. Whenever one assumes that the differences between monozigotic twins are due only to heredity (this is the basis of the twin method), one postulates in fact that environmental influences are of equal importance and act in the woy to differentiate one from the other both monozygotic and dizygotic co-twins.

The comparison between the two types of twins implies the identity of environmental influences and a conception of heredity and environment as indépendant variants.

As far as the psychological environment is concerned, the Author faithfully reports works on twin-condition: psychologically environment is defined according to the structure of the pair, of the duty of each co-twin the pair, and thus: a) two identical twins never hare an exactly identical environment; b) the environment of identical twins is never the same as that of non-identical twins.

Concerning pre-birth and peribirth conditions, the Author reaches the same conclusions of non-comparability between monozigotic twins, dizygotic twins and control groups of non-twins: difference in lenght of pregnancy, in weight at birth, in the rate of stillbirth and new-born deaths, in the mother's age.

The Author concludes not for abandoning the twin-method but for a revision of the criteria, and for a change of perspective.

The failure of comparison and of mathematical analysis applied to the difference between heredity and environment is not. completely negative. It reveals the inadequacy of such criteria at least in the field of psychology, and leads to overcoming them. The psychological environment does not appear as a still picture, but rather as a situation defined by the inter-social and differential duties. Furthermore, heredity and environment are variants closely dependent on each other.

In this study of 53 twin pregnancies, the plasma concentrations of the placental proteins, placental lactogen (hPL), and pregnancy-specific glycoprotein (SP1) were measured. Placental lactogen was found to be of more value than SP1 both in the detection of twins and in assessment of fetal growth. Serial measurement of either protein would seem to be more useful in assessment of fetal growth than single measurements. Preliminary studies of the less well known placental protein, PP5, in a small series of twin pregnancies indicate that it may also prove to be of clinical value in the detection and monitoring of twin pregnancies.

A model of nature-nurture interaction in school situations emanating from a longitudinal Swedish twin project is presented. This model implies that interactional effects measured by MZ-DZ within-pair comparisons over time are related to the type of behavior studied, as well as teacher and pupil influences at different levels. In a more permissive and stimulating school situation, hereditary factors are hypothesized to be more influential (decisive for behavioral variation) than in a more restrictive and nonstimulating situation. A study of such interactional effects will require longitudinal measurements of pupil behavior as well as teacher and parental influences. To acquire a variation in permissiveness/restrictiveness and stimulation/nonstimulation at the societal level, comparisons are made between twins attending grade 4-6 in compulsory schools in Sweden and twins of the same age attending Israelian Kibbutz schools.

The different varieties of congenital dyschromatopsias are inherited following different modes. The dyschromatopsias of the protan and deutan type, as well as the atypical achromatopsia (blue mono-cone monochromacy), are sex-linked recessive, the tritanopia probably autosomal dominant and the typical achromatopsia surely autosomal recessive. The mode of transmission of the tritanomalia is still dubious.

Concerning the localisation of the genes on the X chromosome, the bilocular theory for the deutan and protan genes is accepted at the present time. These genes form a cluster with the genes of hemophilia A and G6PD deficiency. It is possible that this cluster is situated on the short arm of the X chromosome or on the long arm near the centromeric region. The exact situation will be known very soon, when the interpretation of the results of the cellular hybridisation, which are still discordant, will be well established.

Two pairs of sisters are reported who showed clinical, morphologic, and hormone abnormalities, such as to be classified in the picture of the so-called Stein-Leventhal syndrome.

These cases, as other few similar observations, may suggest the possibility that, at least in some instances, the Stein-Leventhal syndrome can be governed by factors of a genetic order.

After a short review of the literature on this subject, it is pointed out that enough evidence supports the existence of predisposing genetic factors to the manifestation of the syndrome, although a true heredity of the disease cannot at the moment be entirely supported. Also some fraternal cases could find an explanation in lesional actions repeated during subsequent pregnancies.

Advances in computer technology have made possible a greater sophistication in the statistical analysis of pedigree data, however this is not necessarily manifest by fitting more comprehensive causative models. Planned twin and family studies measure numerous explanatory variables, including perhaps genetic and DNA marker information status on all pedigree members, and the cohabitation of all pairs of individuals. A statistical analysis should examine the contribution of these measured factors on individual means, and in explaining the variation and covariation between individuals, concurrently with the postulated effect of unmeasured factors such as polygenes. We present two models that meet this requirement: the Multivariate Normal Model for Pedigree Analysis for quantitative traits, and a Log-Linear Model for Binary Pedigree Data. For both models, important issues are examination of fit, detection of outlier pedigrees and outlier individuals, and critical examination of the model assumptions. Procedures for fulfilling these needs and examples of modelling are discussed.

The results are presented of a method of generalized distances calculated by a noncentral χ2 test and applied to compare 63 twin pairs and 196 sib pairs. The advantage of this method in biometrical analysis lies in the fact that several measurements can be utilised simultaneously. Besides, it takes into account the distance of each relative to the centre of the population and also has the advantage of permitting the comparison of distances between pairs of relatives whatever their age or sex.

Generalized distances were calculated for four measurements of the head, five of the body and eleven of the face. For all three sets of measurements the influence of genetical factors was demonstrated. The body seems less influenced by environmental factors and more conditioned by genetic ones.

The palm prints of a 2A,XY/3A,XXY patient displayed a scarcity of patterns and a wider than normal atd angle. Both hands had typical four-finger lines. The digits of the right hand had radial loops on II, III and V.

A simple program for management of term twin delivery in the second stage of labor is presented. Provided that given selection criteria are met, twins at term are delivered by the vaginal route

The are two common replies to the question of whether carriers of genetic disorder should have children. The first simply ends any argument by claiming that everyone has an inalienable right to have children. In many ways this view is quite attractive. The right is said to be universal as well as inalienable. It avoids odious comparisons and applies to everyone, including those whom society has deemed unfit for the flimsiest reasons.

In the United Kingdom, for example, a High Court judge recently upheld the decision by Sheffield Health Authority to refuse IVF treatment to Julie Seale, who was then 36, on the grounds of her advanced age. This latest salvo in what one writer has called “the fertility war” follows on from the Grand Peninsular Campaign against IVF treatment for post-menopausal women and the recurrent guerilla battle over enforced sterilisation. As this author remarks, “What has happened without our really noticing it is that, with every new skirmish in the fertility war, we are becoming more and more comfortable with the idea that some people deserve to be parents more than others” [1]. And in an age of what is essentially payment by results, there is a great temptation for healthcare providers to think that those who deserve to be parents are those with the best clinical chances.

Phenotypic variation in human population may contain contributions from a number of different sex-associated genetic influences. These influences include maternal effects, the effects of sex-linked loci, and the effects of sex-limited autosomally linked loci. The families produced by MZ and DZ twins provide statistics which permit the detection and estimation of these effects. In particular, they provide statistics derived from various types of age-matched half-sibs and cousins in addition to those derived from the more usually studied full-sib or parent-offspring relationships. Specific models for genetic maternal effects, sex-linkage and sex-limitation are used to explore the use of extended twin design for the detection of and the discrimination between various sex-associated effects. The sample sizes required to detect maternal effects and sex-linkage were considered for some simple cases and it is concluded that comparison derived from the progeny of twins will often provide better tests for these effects than those derived from parent-offspring comparison.

A case of a female newborn, followed up to the 9th month of life, presenting a clinical picture of multiple malformations, typical of trisomy-18, is reported by the AA.: microcephaly, low set of ears, micrognaty, ogival palate, superabunding skin in the neck, simian crease, typical hands attitude, luxation of the right hip, severe neurological symptomatology with the characteristic rigidity and, finally, an extremely severe mental defect.

Growth has always been very poor; death occurred at the 9th month of life.

Chromosome research, done with two cultures of capillary blood, revealed the presence of two lines of normal and trisomy-18 cells in similar percentage.

The literature concerning the subject is examined and discussed.