Section 16 — Human Cytogenetics 



ease (interventricular septal defect) had two acro- 

 centric chromosomes involved, one long and 

 one short. In both chromosomes a prominent 

 segment was apparent between the short arms 

 and the satellites, therefore showing two sec- 

 ondary constrictions in the short arms. The 

 inserted segments were a bit longer than the 

 normal short arms which were also present. The 

 third patient, a 35-year-old female with chro- 

 matin-positive primary amenorrhea and very 

 short stature, showed gonosomal mosaicism 

 (isochromosome-XX/XO). In addition, one small 

 acrocentric chromosome was noted to have a 

 very prominent fragment inserted between the 

 short arms and the satellites, appearing exactly 

 like the chromosome described for case 2. Only 

 in the last case was there a possible source for 

 the fragment ; for example, part of the short 

 arms of one X. The parents of the other two 

 cases are being investigated to see if the unusual 

 chromosomes found in the propositi might be 

 present in their karyotypes as well as some ob- 

 vious deletion in another chromosome. Our 

 working hypothesis is that this additional bit 

 of chromosomal material may be responsible 

 for a partial trisomic state in the propositi. 



16.19. Chromosomal Break in Autosome No. 2, in a 

 Patient with Hypogonadism. H. van den 

 Berghe, H. Verresen, W. de Loecker, O. 

 Steeno, and P. de Moor (Louvain, Belgium). 



A break of the two short arms of one auto- 

 some no. 2 has been discovered in a 47-year-old 

 male patient. Numerous chromosomal prepara- 

 tions were obtained from leucocyte cultures at 

 different time intervals. The scission of the two 

 short arms of one autosome no. 2 occurred 

 in the direct neighbourhood of the centromere, 

 these two separated arms staying attached to 

 each other in all the cells. 



This chromosomal material, initially belonging 

 to the autosome no. 2, was found to be transfer- 

 red and attached either to autosome no. 21 or 

 22, or even existing freely between the other 

 chromosomes. This phenomenon was found to 

 exist in all the examined cells. All the cells 

 have 46 chromosomes. 



The clinical picture of this patient showed 

 hypogonadism of testicular origin, disturbed 

 anabolic features, and a series of secondary 

 abnormalities. The sex-chromosome-comple- 

 ment is XY in all the cells, and Barr-chromatine 

 in buccal smear being negative. The karyotype 

 in one parent and seven sibships was equally 

 studied. 



The incorporation of thymidine- 3 !! and gly- 



cine-2-C 14 into the chromosomes of the cells of 

 this specific case were performed. The effect of 

 scission of one chromosome and the degree of 

 incorporation of radioactive precursors into the 

 different sections of the chromosome involved 

 as well as in the free existing fragments was ex- 

 amined. 



16.20. Chromosomal Abnormalities in a Familial 

 Syndrome Involving Labial Fistulae with or 

 without Hare Lip and Cleft Palate. Adriana 

 De Capoa, M. Siniscalco, and D. Tarsitani 

 (Rome, Italy). 



Among the types of autosomal trisomies 

 hitherto described and confirmed, cleft palate 

 and hare lip are often present though accom- 

 panied by other congenital malformations. 



On the other side, in individuals showing 

 cleft palate and hare lip unaccompanied by other 

 congenital anomalies, chromosome studies have 

 failed to show significant abnormalities. 



The authors have recently observed a family 

 involving a mother and eight children, seven of 

 which show labial fistulae associated in five 

 cases with hare lip and cleft palate. Chromosomal 

 studies performed on peripheral blood of 

 the mother and three of the affected children 

 showed the existence of an autosomal mosaicism, 

 involving an additional chromosome, apparently 

 belonging to group 4-5. In all the patients, 

 besides the cells with the extra chromosome, an- 

 other abnormality was found in all mitoses 

 observed: i.e. a small centric chromosomal frag- 

 ment seemed to be constantly present, while 

 one chromosome of group 18-20 was missing. 

 This fragment seems to pair with the long arm 

 of one of the chromosomes of group 18-20, and 

 it could therefore be interpreted as the missing 

 chromosome, carrying a deletion on its short 

 arm. The father was also studied and his chro- 

 mosome complement was found to be normal. 



The interpretation of these findings is, for 

 the time being, very difficult and indeed hazard- 

 ous. However, even at this stage, a few conclu- 

 sions can be tentatively drawn: 



(i) On the basis of nuclear sexing, an involv- 

 ment of the X-chromosome in the abnormal 

 cells can be excluded ; 



(ii) It is very unlikely that the two chromo- 

 somal abnormalities are independent of each 

 other, and probably the delegation affecting the 

 small submetacentric chromosome, being pres- 

 ent in all the cells, is likely to be the primary 

 defect. 



(iii) The absence of severe malformations and 

 of mental retardation makes plausible the hy- 



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