On the basis of serological observations in male twins of group A2 with irregular Anti-A1 (α1,) agglutinins in the serum the possibility of an inheritance of these antibodies is indicated. Further additional five individual observations are included.

Simultaneously it was possible to obtain in the above indicated twins a triple group-and factor paternity exclusion.

The following is proposed:

1. To place on a broad basis the examination of the inheritance of irregular Anti-A1 -Agglutinin.

2. To evaluate the previous «exceptions» to the rules of genetics concerning the system of blood groups and blood factors in the light of the currently known serological and anthropological armentarium.

Report about the problem of hereditary and non-hereditary causes of some typical human malformations by genes and phenocopies.

The example of mongolism shows that besides a genetical cause in some cases the opinion of a «dysplasmatical» origin in others is well proved.

Malformations of the medullar part of central nervous system, especially their severest forms as anencephaly and spina bifida aperta can be inhereted or non inhereted.

The German statistics after last world war (especially in the Russian zone) show, that anencephaly and spina bifida are most phenocopies.

Harelip and cleft palate are inhereted in the rule.Phenocopies are rare.

Malformations of the extremities are more inhereted than non inhereted. There are phenocopies, but more seldom than pathological genes. Their possibility is also given by the example of the well known experiments.

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.

Report of the result of familial examinations on 49 stillborn of before half year of life died and dissected children with lethal anomalies.

1. In two of 4 families, whose probands suffered from harelip and clett palate combined with other deformities, is supposed, that—just like harelip and clett palate without other malformations—an unstable dominant gen being origin of the mistake of development.

In one case with a special severe combination and probable consanguinity of the parents is to think of homozygoty.

In a fourth case the question of the origin of the combined deformities by « psychical trauma » may be discussed.

2. In 32 families the cause of death of the probands is to be seen in a lethal closing mistake of the vetebral column.

a) In seven of 20 families with an anencephalus signs of « Dysraphies » and other anomalies were found which may be caused by pathological gens. One time both parents of a (homozygote?) anencephalus who showed deformities of heart and limbs had Spina bifida occulta.

b) In 5 of 12 families with Spina bifida aperta was the cause of deformation an unstable unregular dominant gen. In two other families is this probable.

Anencephalie and Spina bifida aperta may be found together in the same family. Heterogenie ist probable for both.

3. a) Hydrocephalie without other deformities was in 8 families not inherited.

b) 4 families with microcephaly showed differences. Dominant gens for « Dysraphies » and recessive gens may bring about microcephaly.

c) Consanguinity of the parents in a case of cyklopy is seen to be sign of recessive inheritance.

This paper is based on 45 cases in 27 families, all of which have been studied in Children Hospitals. In Switzerland almost all cases of infantile amaurotic idiocy (Tay-Sachs) have probably been collected, so that the stated 13 primary and 14 secondary cases may allow an estimation of the frequency of this character, which seems to oscillate temporarily. In the last 10 years no new cases have been observed.

All 24 autochthonus Swiss cases are from non-Jewish, mostly rural origin, in which Eastern Jews are not to be supposed as ascendants.

Our in all 27 families with TS make Slome's statistic of Jewish and non-Jewish cases in literature much more significant; the incidence of parental consanguinity is, as a matter of fact, nearly twice as high in families with non-Jewish origin.

There is no evidence of a milder and longer course of TS in non-Jewish families.

The mode of inheritance is, according to Slome, monohybrid autosomal recessive, though in remarkably many sibships there is an accumulation of cases. The reduction method, however, gives a percentage of 28,3 ± 6,2, coming quite near to the expectation of the Mendelian quarter.

The penetrance of the character is total, the expressivity generally very equal, with only a few deviations from the well—known clinical picture of TS.

The interfamiliar and intrafamiliar variability therefore is small. In not even one of the families studied have there been found other forms of lipoidosis, principally no cases of splenohepatomegalia Niemann-Pick. All available respective cases in Switzerland have been collected by the present author and will soon be published in these Acta. In none of these families with M. Niemann-Pick have cases of M. Tay-Sachs been seen. This fact is liable to prove that these clinically and anatomically very similar conditions derive from independent i. e. different mutations.

Modifying genes may account for the incidence of sibships in which all or almost all children died from M. TS.

Environmental influences do not seem to favour its manifestations.

If in the newer literature from the U.S.A. the Jewish cases of M. TS are still prevalent and if, as we heard, the concomitant manifestations occur fairly often in Israel, the origin may be sought in one at least 200 years old respective mutation in the Jewish population of a relatively restricted White-Russian era.

1. We discuss previous casuistic reports published until now on twins suffering from hereditary deafness of the dominant type.

2. One case of hereditary deafness in a pair of monozygotic twins is reported, the twins showing no considerable difference in their acustical defect.

Prove that deafness in this case was conditioned by heredity and did not arise from an explosion, is given by the mono-zygozity of the patients.

3. It is imperative that each case of questioned hereditary deafness described above should be controlled by audiometric test.

The authors describe a new case of degenerative nanism « typus amstelodamensis », which shows all fundamental characteristics of the syndrome. From the hormonic research, which was carried through for the first time, resulted normal values (for the age of patient); this fact proves the fundamental normality of the endocrine system, which was already found by De Lange in the anatomical-pathological field.

Moreover, the genealogical examination led for the first time to the assumption of the existence of a genetic factor causing this particular type of a multiple degeneration.

The a gives a general survey of the cardinal signs of the dysostosis mandibulo-facialis described, 1944, by A. Franceschetti and P. Zwahlen, and mention the 11 familial types of this clinical picture. He adds his 12th family where the father and two children are afflicted with the same dysmorphosis of the mandibulofacial type.

A comparative of the show the malformations of the thre members of this family. The diagnosis dith the new type of dysostosis described by Ullrich and Fremery-Dohna is also mentionned.

Two cases of cudden non-traumatic death associated with physical exertion in identical twins. The one observation concerned a famous rugby player who died immediately after a competitive game. Autopsy revealed cardiac hypertrophy and advanced myocardial fibrosis, excess lymphoid tissue, a larghe thymus gland with active Hassals bodies and hydronephrosis of the left kindney. A twin brother of the deceased died at about the same time during swimming. The second instance was studied by O'Brien. It refers to a man age 26 who died during physical work on the farm (pulling sugar beets). Post mortem examination showed a hemmorrahagic cyst with a pigmented wall and a thrombosed aneurysm of the left middle cerebral artery which had leaked. An identical twin brother of this man had died a short time previously while playing tennis.