Section 16 — Human Cytogenetics 



systems, low set malformed ears, slight hyper- 

 telorism, bilateral blepharophimosis and colo- 

 boma of the iris, micrognathia and macroglossia. 

 There were also malrotation of the small 

 intestine, omphalocele, hiatus hernia, dilatation 

 of the renal pelves, absence of one umbilical 

 artery and anal atresia. The finger and toes were 

 long, and there was a distinct gap between the 

 first and second toes bilaterally. There was 

 marked muscular hypotonia and the deep tendon 

 reflexes were weak. The heart and genitalia were 

 normal. The child died at the age of six months. 

 An EEG was normal. Numerous vacuolated 

 mononuclear cells were found in the peripheral 

 blood and in the bone marrow. 



The mother had had five pregnancies. The 

 first child was a male who died shortly after 

 birth. The second pregnancy resulted in a normal 

 male child. The next two pregnancies terminated 

 in early abortions. The present case was the 

 fifth pregnancy. 



Chromosome studies of cultured skin and bone 

 marrow cells of the propositus showed a chromo- 

 some number of 46 and an XY sex chromosome 

 constitution. There were only three chromosomes 

 in group G (21-22), and there was an odd 

 chromosome which could not be paired. The 

 mother, who was phenotypically normal, had a 

 chromosome complement of 46 in cultured skin 

 cells. ? n addition to the same abnormalities 

 present in the karyotype of her son, one of the 

 chromosomes in group B (4-5) lacked the short 

 arms. The karyotype of the father was normal. 



The most likely interpretation of the chromo- 

 some abnormality is a translocation involving a 

 chromosome of group 4-5 and a member of 

 group 21-22. 



16.24. Multiple Congenital Anomalies with Autosomal 

 Trisomy amongst the Chromosomes of Group 

 16-18 and Their Possible Relations to the "Dys- 

 cranio-Dysphalangic-Syndromes." M. Tolks- 

 dorf, H. G. Hansen, H. R. Wiedemann and 

 W. Lehmann (Kiel, Germany). 



We discuss the autosomal trisomy amongst 

 the chromosomes of group 16-18 associated 

 with multiple congenital abnormalities. 



In view of the similarity in the clinical pattern 

 of the anomalies in cases so far published we 

 regard some distinctive clinical findings and other 

 features occurring facultatively. 



In this connection we give a report of a prema- 

 ture female child with multiple anomalies and a 

 trisomy 17 demonstrated in blood and bone 

 marrow cells. 



Moreover, we shall try and find possible 



relations between the cases with trisomy amongst 

 the chromosomes of group 16-18 and the various 

 types of the "Dyscranio-Dysphalangies" (Gi'in- 

 ther). 



16.25. (D.) Trisomy 17 associated with Multiple 

 Congenital Anomalies. H. G. Hansen, 

 M. Tolksdorf, W. Lehmann and H. R. Wie- 

 demann (Kiel, Germany). 



We demonstrate figures of a premature female 

 infant with a relatively paraphased combination 

 of congenital abnormalities. Cytological studies 

 on her blood and bone marrow cells were 

 carried out on short term cultures. The results 

 show a chromosome number of 47 with a trisomy 

 amongst the group 16-18 in the great majority 

 of cells of both cultures. 



Some mitoses and karyotypes are demon- 

 strated. 



16.26. Discordant Mongolism in Monozygotic 

 Twins? J. W. Bruins, J. van Bolhuis, 

 J. B. Bijlsma and L. E. Nijenhuis (The Ne- 

 therlands). 



In 1 956 van Beukering and Vervoorn published 

 a case of negro-twins, one of which suffered 

 from Down's syndrome (mongolism). Investi- 

 gation of the placenta (plate) proved the twins 

 to be monozygotic. So this would be a case in 

 point of discordant mongolism in uni-ovular 

 twins. It was not possible to examine the blood- 

 groups or the chromosomes of these negro- 

 twins. 



If the general karyotype of the child with 

 Down's syndrome presented 47 chromosomes, 

 this would be a case of non-disjunction which 

 occurred in the fertilized human egg. Instead of a 

 derangement in the meiosis, it would be here 

 non-disjunction in the mitosis. 



On October 4, 1962, at Deventer (Nether- 

 lands), a pair of twins was born that at first 

 was taken to be dizygotic on account of anthro- 

 pometrical differences. One of the twins was 

 normal, the other showed nearly completely 

 Down's syndrome. Unfortunately the placenta 

 was not examined but examination of the 

 bloodgroups indicated that the twins were 

 monozygotic. To test this, a small reciprocal 

 skin-transplantation will be made. 



The number of chromosomes of the cultivated 

 white blood cells was 47 for the diseased child, 

 and 46 for the normal one. So they are "mosaic- 

 twins", at least if there has been one cell in the 



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