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Downloaded from http://jmg.bmj.com/ on June 14, 2017 - Published by group.bmj.com Journal ofMedical Genetics, 1978, 15, 388-390 Pericentric inversions inv(2)(p q 13) and inv(2)(p1 3q 1) in 2 unrelated families1 RUTH B. PHILLIPS From the Department ofZoology, University of Wisconsin, Milwaukee, Wisconsin, USA Pericentric inversions in chromosome 2 were traced in 2 unrelated North American black families. In the case of inv(2)(pl3qll) no effect on reproduction was observed. In the case of inv(2)(p 1q13) some reproductive abnormalities were noted which might be related to the inversion. SUMMARY Although a reduction in fertility might be expected in inversion heterozygotes, evidence for this is limited (Moorhead, 1976). In the case of chromosome 2, 3 unrelated families with abnormal reproductive history were found to have inv(2)(pllq13) in a recent study (Leonard et al., 1975). Since the frequency of this inversion in the normal population is not known, it is difficult to be certain of the effect of the inversion on reproduction. In the present study this inversion and a similar one were found in families with sickle cell trait who were karyotyped in connection with a family 'This work was supported by a grant from the National Institutes of Health (AM 16886). Received for publication 30 November 1977 study to determine linkage relation with the ,haemoglobin gene. Materials and methods The probands were karyotyped in a chromosome survey of relatives of sickle cell anaemia patients. Both of the probands had normal haemoglobin. The husband of proband 1 had sickle cell anaemia, and the husband of proband 2 had sickle cell trait. Peripheral blood lymphocytes were cultured according to a modification of the method of Moorhead et al. (1960), with colcemid treatment of 2 to 4 hours. Air dried slides were prepared and stained with 0.5% p13 q 11 Normal 2 Irv 2 (pllql3) Normal 2 388 Inv 2 (p13 qll) Fig. 1 Diagram of normal chromosome 2 (left) and its inverted homologue (right) from 2 families. Lines indicate points of breakage. Downloaded from http://jmg.bmj.com/ on June 14, 2017 - Published by group.bmj.com Pericentric inversions inv(2)(pJJql3) and inv(2)(pJ3qll) in 2 unrelatedfamilies 389 rarncv 2 Atebrin and mounted in 70% sucrose for fluorescence microscopy. Karyotypes were prepared according to the Paris Conference (1971). Results and discussion Chromosome analyses were carried out on cultured peripheral blood lymphocytes of 14 family members from 2 families. The results of the analyses are shown in Fig. 1, 2, and 3. Fig. 1 is a diagram of the 2 inversions showing the probable breakage points. Fig. 2 and 3 are partial karyotypes showing chromosome 2 in all of the individuals from the 2 families. In Family 1 the mother had inversion inv(2)(pllq 13) and it was found in 2 of her 3 children (Fig. 2). The mother had 4 miscarriages, 3 known to be spontaneous. In Family 2, the mother had inversion inv(2)(pl3ql 1) and it was found in 2 of her 7 children (Fig. 3). There was no record of miscarriage or other reproductive abnormalities in this family. The fact that reproductive abnormalities occurred in the family with inv(2)(pllql3) is particularly interesting in view of the recent report (Leonard et al., 1975) that 3 families with abnormal reproductive history were found to have this same inversion. The frequency of this inversion in the normal population appears to be low, with 1 case in 11 680 newborn infants found by Jacobs et al. (1974). The finding of reproductive abnormalities associated with this inversion in this study suggests evidence for a correlation IM"I Mother /~ C hIt 1 ..f 2K: 4 '-ther- d2 Chic 3 rCKd Fig. 3 Partial karyotypes of Family 2 showing chromosome 2. Arrows indicate inversion inv(2)(pl3ql 1) i 6 Chmd5CSr-d chromosomes. Fr ather Mother z I Child 3 Child 2 Chi[d 1 Fig. 2 Partial karyotypes ofFamily I showing chromosome 2. Arrows indicate inversion inv(2)(pllql3) chromosomes. between inversions and increased pregnancy wastage. No report of reproductive abnormalities with inv(2)(p13ql 1) is available. A similar inversion in which the centromere was more terminally located was followed in 1 family for 3 generations (Weitkamp et al., 1969). Most of the individuals appeared to be normal. The inversions reported in this paper were found in 2 of 17 North American black families karyotyped in a linkage study. In this same group inv(9)(p l 1q 1 3) was found in 2 families and inv(l)(p 1q12) was found in another family. This high frequency of pericentric inversions supports an earlier report (Lubs and Ruddle, 1971) of a higher frequency of pericentric inversions in a newborn black population compared with a newborn white population. References Jacobs, P. A. Melvin, M., Ratcliffe, S., Keay, A., and Syme, J. (1974). A cytogenetic survey of 11,680 newborn infants. Annals of Human Genetics, 37,359-368. Downloaded from http://jmg.bmj.com/ on June 14, 2017 - Published by group.bmj.com 390 R. B. Phillips Leonard, C., Hazeal-Massieux, P., Boequet, L., Larget-Piet, L., and Boue, J. (1975). Inversion pericentrique inv(2)(pl 1q13) dans des familles non apparentees. Humangenetik, 28, 121-128. Lubs, H. A., and Ruddle, F. H. (1971). Chromosome polymorphism in American negro and white populations. Nature, 233, 134-136. Moorhead, P. S. (1976). A closer look at chromosomal inversions. Birth Defects. Original Article Series, 8, No. 7, 1972. The National Foundation-March of Dimes, New York. Weitkamp, L. R., Janzen, M. K., Guttormsen, S. A., and Gershowitz, H. (1969). Inherited pericentric inversion of chromosome number two: a linkage study. Annals of Human Genetics, 33, 53-57. American Journal ofHuman Genetics, 28, 294-296. Moorhead, P. S., Nowell, P. C., Mellman, W. J., Battips, D. M., and Hungerford, D. A. (1960). Chromosome preparation of leukocytes cultured from human peripheral blood. Experimental Cell Research, 20,613-616. Paris Conference (1971). Standardization in human cytogenetics. Requests for reprints to Dr Ruth B. Phillips, Department of Zoology, University of Wisconsin, Milwaukee, Wisconsin 53201, USA. Downloaded from http://jmg.bmj.com/ on June 14, 2017 - Published by group.bmj.com Pericentric inversions inv(2)(p11q13) and inv(2)(p13q11) in 2 unrelated families. R B Phillips J Med Genet 1978 15: 388-390 doi: 10.1136/jmg.15.5.388 Updated information and services can be found at: http://jmg.bmj.com/content/15/5/388 These include: Email alerting service Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article. 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