A prospective study was undertaken to determine the effect of twin birth-weight discordancy on Apgar scores and umbilical blood acid-base parameters. Using the paired t-test, small but statistically significant differences were seen in these parameters favoring the heavier twin over its lighter sibling. These differences were also affected by birth order, with the first-born being favored.

The traits, earlobe attachment, hand clasping and arm folding, are found to show a high degree of homogeneity in the Tamil Brahmans.

The latter appear to be closest to the Bengali Brahmans, with respect to all three traits, and differ significantly from other Brahman populations, with respect to earlobe.

The authors have analysed the frequency and structure of congenital anomalies in children born in the Pomeranian district in the period from 01.07.1997 to 31.12.1998. Among a total of 28.361 births in that area, 748 (2.64%) were affected by congenital anomalies. Among 28.361 births, 620 (2.18%) were from multiple pregnancies. 23 (3.71%) among births from multiple pregnancies were affected by congenital malformations. The prevalence rate of inborn anomalies in births from multiple pregnancy in our area were higher (3.71%) in comparison to births from singleton pregnancy (2.61%). It implies that children born from multiple pregnancy are at higher risk of developing congenital anomalies.

A case of monoamniotic monochorionic (MAMC) female twins, with one twin being anencephalic, and the co-twin being normal, is reported. Twin to twin transfusion syndrome was also noted. The reasons for anencephaly in association with monozygotic (MZ) twinning are discussed. The management of such a case is presented.

The fact that controls as are maintained in most biological experiments, could even be studied ebulliently in human population, by observing a MZ pair, a member of which is exposed to a certain anomaly and the other acts as control, becomes more vivid and recommended from the present studies. For, they can be directly related to human health and welfare.

Permanent changes due to typhoid incidence in physical, mental and anthropometric traits of a member of MZ twin pair may be suggestive of some “beneficial interaction of typhoid bacillus with certain intricate mechanisms like RNA and protein synthesis, as has been envisaged earlier.

After an earlier report about twins and sports the question of dependence of the aptitude for sports from the genotype is again examined. Examples are provided by families of famous international sportsmen as well as by families from own larger examinations.

It is established that the proportion between parents and siblings in the sport-families is about 1: 1 and probably dominant genes are the cause of hereditary talents for sports. No evidence could be given for recessive inheritance.

As sporting talents are to be seen in many different forms, several independent genes for sporting endowment and accordingly heterogeny may be supposed.

As the results of the twins examinations have shown, further examinations on families with special sporting capacity remain to be seen.

The result of the examinations of Prof. Dr. Luigi Gedda are of special importance.

187 patients suffering from renal lithiasis have been examined to find out an association with ABO blood groups. It has been found that the incidence of Renal Lithiasis is comparatively higher in the patients of blood group A than in those of blood group O. The difference in percentage ratios A/(A+0)% in patients and controls is 17.96; the χ2 17.4331 for one degree of freedom shows that it differs from unity significantly. The frequencies of renal lithiasis in persons of blood group A against those of B, O and AB are 1.91, 1.59 and 1.31 respectively.

This study considers the replies to a 14-item questionnaire, by 27 monozytogic (MZ) and 38 dizygotic (DZ) pairs. Another sample consisting of 48 sets of parents of twins (24 of whom were MZ and 24 DZ, not necessarily corresponding to the couples of twins actually studied) was used, to answer a questionnaire directly related the one put to the twin pairs. The results of statistical tests performed (canonical correlation and Fisher's discriminant) indicate that only in MZ twins does self-awareness outweigh pair-awareness. This does not seem to be related to any difference between MZ and DZ twins in the education/upbringing received from their parents.

Out of 446 twin births in 1946-1971, 177 (19.8%) were stillborn or perinatally dead. The main reason of twin perinatal mortality is prematurity, which is also confirmed by clinical and anatomopathologic findings. The essential role in the reduction of perinatal mortality is being attributed to ambulatory “K” Centres through early diagnosis of multiple pregnancy and pregnant women hospitalization at 30-32 weeks of pregnancy.

Till to-day there are very few concordant and discordant twin pairs known with regard to chondrodysplasy. We describe here a family in which as well the mother as also her both twin daughters are affected with this disturbance of development. The monozygosity of the sisters is beyond all doubt.

The concepts of dominance and recessivity as applied to human genetical traits are losing their original connotations. It is better to speak of genes unconditionally deleterious in heterozygote form and those for which such disadvantage is doubtful. The classical dominant traits come into the first category and in the large majority they give rise to grossly pathological conditions and are ipso facto harmful-many in fact are lethal. In the case of these genes it is difficult to conceive that any agency other than recurrent mutation is instrumental in keeping them at their present frequency.

Assuming that such mutation rates are of the same order of magnitude over the entire spectrum, the frequency of these traits will vary inversely with their severity and this is found to be approximately true-from an incidence of 3/million for an almost invariably lethal trait such as acrocephalosyndactyly to 1/1000 for a relatively innocuous trait such as ptosis.

We would not expect genes even at the higher of these frequencies to be often seen and recognised in homozygote form with the low degree of inbreeding prevalent in human populations. This is in fact confirmed in practice and examples of possibly homozygous forms or dominant conditions are very rare. To be recognized as causing a recessive trait, with a few exceptions in inbred communities, a gene must be more common and often cannot therefore be maintained by recurrent mutation alone. Very wide geographical variations in the incidence of such traits also militate against such an interpretation. Phenylketonuria is an excellent example. The abnormal gene reaches a frequency of as much as 1% in some populations and it is unknown in others.

Under the name of “Progenesis” (from the prefix “pro “, in front, and of the Greek “genesis “, generation) a new conception and classification of the factors of development were proposed by R. Turpin, the progenesis grouping “the whole of the hereditary and non hereditary factors that preexist to the fecundation and that concur to the formation of the being and to its development”.

This conception has the advantage of designating indifferently, to all progenitic factor, hereditary as well as non hereditary, a place marked in advance; it has the advantage of showing beside the paternal maternal factors, the characteristic progenetical factors of the couple; it has the advantage to draw the attention on factors which were before neglected (age of mother, age of father, rank of birth, sex of the preceding pregnancy, interval between pregnancies, number of pregnancies, etc.) and whose importance increases in proportion as the gathering of the facts is abundant enough to lend itself to the statistical analyses; it has lastly the advantage of leading to an etiological prevention of the congenital defects, trying to draw the most advantage from the surrounding factors, without discarding, when they are imposed by the circumstances, the possibilities brought to their right proportion of the eugenic selection.

To illustrate this progenesic conception of the ontogenesis a simple example, the gemellity, deserves to be retained.

If we consider the gemellity as a deviation in regard to the simple pregnancies, it constitutes at the same time the more frequent and the best registered of anomalies. It lends itself to the study of its relations with divers progenesic factors which the authors regard by turns with the complement of their personal researches : age of the progenitors, rank of the pregnancy, sex of the product of the anterior last conception.

If on the other hand, we consider the gemellity itself as a progenesic factor, we can study on the development, and for instance, which the authors have done, on the rate of masculinity. This study has lead them to put in value the phenomenon of diminution of the masculinity in relation to the degree of the multiplicity of pregnancy.

In order to evaluate the influence of birth order and fetal presentation on antenatal growth of twins we conducted a comparison of prospective measurements of five fetal biometric indices in 50 vertex-vertex and 47 vertex-breech twins. We compared (a) twin A to twin B in both groups; (b) the second and (c) the first twins of both groups. Both groups had similar maternal and neonatal characteristics. The growth curves of the twins were also very similar except for three significant (p<0.05) deviations: (a) Twin A of the vertex-vertex group, had larger femur length (FL) at 18-19 weeks, abdominal circumference (AC) and estimated fetal weight (EFW) at 29 weeks, and EFW measurements at 36 weeks, (b) Second breech twins, compared to their second vertex cohorts, had significantly smaller biparietal diameter (BPD), head circumference (HC) and FL at 18-19 weeks, BPD and HC at 29 weeks, and EFW at 37 weeks, (c) First twins of the vertex-breech group, as compared to first twins of the vertex-vertex group, had significantly smaller BPD and AC at 18-19 weeks, FL and AC at 21-22 and 29 weeks, FL at 31 weeks, and EFW at 27-28 and 36 weeks' gestation. We concluded that significantly different sonographic fetal indices may be measured at about 20 and 30 weeks' gestation, but not later. An adaptive mechanism attributed to fetal presentation is suggested to explain similar birthweights in spite of these antepartum differences.

Roentgenograms have been taken of the hand and wrist on 58 pairs of MZ twins, on 40 pairs of DZ twins, and on 4 groups of triplets, between 2 and 18 years of age.

Their comparative examination has shown the highest concordance in MZ pairs and a remarkable discordance in DZ pairs, accentuated above all in those of opposed sex. Generally, the comparison between male and female pairs of same age has shown a delay on bony growth of the firsts, event remarkable also within DZ pairs of opposed sex.

Comparing the Roentgenograms taken with those standard of Greulich and Pyle, generally it is to be remarked that males are retarded in regard to females.

Some cases of concordant paramorphysms in healthy pairs of MZ twins and of remarkable immaturity in MZ pairs at the same time sick are also shown.

I wish to thank Professor Paolo Durand, Director of the International Centre of Paediatric Genetics at the Mendel Institute, for his kind words and I particularly thank him for having proposed this celebration to mark the 40th anniversary of the foundation of the Institute.

Somewhat audaciously, I borrow a metaphor when I say that the real foundation stone of the Mendel Institute is the book, “The Study of Twins” here on the bookrest [Fig. 1]. This rather large volume carries works I had collected and developed in Rome over the previous years. In the main, it relates to clinical research work which for me began in an orphanage, not too far away from here on via Nomentana, where I encountered a pair of identical twin brothers, Romolo and Remo [Fig. 2]. The boys were so alike physically that I constantly confused the two and it was this experience that drew my attention to the twinning phenomenon. The book also contains a bibliographic list of over 7,900 studies carried out on the subject of twins. One of the first, of course, is that of Darwin's cousin, Francis Galton and another example from a later period is that of Chiarugi, the Florentine anatomist.

Published in 1951, “The Study of Twins” provoked such overwhelming interest in the medical world that it led me to vigorously promote two initiatives which began to take shape the following year. In 1952 the first issue of the journal “Acta Geneticae Medicae et Gemellologiae” was published and the construction of the Gregor Mendel Institute of Medical Genetics and Gemellology got under way to be finally inaugurated on 6 September 1953. One of the earliest and certainly most important figures in establishing the Institute is here with us today, Dr. Ildo Avetta, the Roman architect who designed the building. Let me take this opportunity to thank him once again for his brilliant work which has drawn the attention and admiration of many over the years.

Here, before you, is the complete 40-volume series of Acta Geneticae Medicae et Gemellologiae from its birth to date. [Fig. 1].