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J Med Genet: first published as 10.1136/jmg.28.9.591 on 1 September 1991. Downloaded from

J Med Genet 1991; 28: 591-595 591 Use of probes for ZFY, SRY, and the Y pseudoautosomal boundary in XX males, XX true , and an XY

Eliana Ternes Pereira, J C Cabral de Almeida, A C Y R G Gunha, Michael Patton, Rohan Taylor, Stephen Jeffery

Abstract the SRY gene with the characteristic of a transcrip- Three XX males, two XX true hermaphrod- tion factor.2 From 50 consecutive sequences recog- ites, and an XY female were studied for pos- nised in this search, only one, PY53-3, was found to sible deletions using probes for the recently be present in some XX males and conserved in all characterised SRY gene and the pseudoauto- eutherian tested. Its homologue in the somal boundary. The XX males and true mouse (p4 2 2) was found in the mutant SXrl that hermaphrodites were negative for all three contains the minimum portions of the mouse Y probes, while the XY female was positive. One known to contain the testis determin- XX male and one XX true ing factor. Transcripts of the SRY mouse homo- were sibs. A previous sib pair of an XX male logue were found in the embryonic gonad during the and an XX true hermaphrodite have been state of Sertoli differentiation.3 This evidence shown to be positive for Y chromosomal makes SRY the best candidate to date for the testis material near the pseudoautosomal boundary. determining factor (TDF) on the in

Thus, both can be produced from man. copyright. different mutations, some involving the SRY The ZFY gene, previously considered as a pos- gene and others not. sible TDF, has now been shown to map 60 kb proximal to the Y pseudoautosomal boundary and is excluded as a candidate for TDF.45 Nevertheless, The search for a gene that induces the first event in ZFY has been recognised in about 70% of the XX testis differentiation has been directed to the se- males tested6 and, in conjunction with probes for the quences of the short arm of the Y chromosome pseudoautosomal boundary region, it can be used to present in XX males. localise segments of the Y chromosome missing or http://jmg.bmj.com/ The smallest amount of that region was recog- transferred in persons with chromosome anom- nised in three XX males and one XX true hermaph- alies. rodite who were negative for more proximal Y In view of the discovery of the SRY gene, we used sequences and for the ZFY gene.' This finding led to probes spanning the region of the Y chromosome a chromosome walk spanning the 35 kb segment from the pseudoautosomal boundary to the ZFY proximal to the pseudoautosomal boundary se- gene to examine the DNA from six subjects: three quence in the Y chromosome, and a recognition of XX males, two XX true hermaphrodites, and one XY female. Two of the patients, one XX male and on September 27, 2021 by guest. Protected one XX true hermaphrodite, reared as a male, are Departmento de Clinica Medica, Universidade brothers and were studied previously with the ZFY Federal de Santa Catarina 88000, Brazil. E T Pereira probe.7 Instituto de Biofionica, Universidade Federal do Rio de Janeiro 20000, Brazil. Materials and methods J C Cabral de Almeida, A C Y R G Gunha PATIENTS South West Thames Regional Unit, St The sporadic cases have not been published pre- George's Hospital Medical School, Cranmer Ter- viously. The XY female is of Caucasian origin and race, London SW17 ORE. the other three subjects are Brazilian. M Patton, R Taylor, S Jeffery Correspondence to Dr Jeffery. FAMILIAL CASES Received for publication 7 February 1991. Case 1 was 14 years old. The was 46,XX Revised version accepted for publication 18 March 1991. in blood lymphocytes and skin fibroblasts (G and C J Med Genet: first published as 10.1136/jmg.28.9.591 on 1 September 1991. Downloaded from

592 Pereira, Almeida, Gunha, Patton, Taylor, Jeffery banding) and he has been reared as a male. There Hybond N + membranes from Amersham were was a uterus, bilateral fallopian tubes, a vagina, a left used. In the former case blotting was overnight ovotestis, right perineal hypospadias, and a right using 20 x SSC, for N+ the process took five hours testis with epididimus and deferens. The ovarian using 0-4 mol/I NaOH. Filters were prehybridised portion contained stroma, follicles, and ova, and the with 0 5 mol/l sodium phosphate/7/. SDS with testicular tissue showed seminiferous tubules, 200 pg/ml denatured salmon DNA. Prehy- hyalinisation, and fibrosis. bridisation and hybridisation were performed at Case 2 was 17 years old. Karyotype analysis was 65'C in a Bachoffer hybridisation oven. The the same as in the brother, case 1. There was hybridisation solution was the same as that used in perineal hypospadias, small bilateral testes normally the prehybridisation, plus a radioactive probe. Pre- placed, and absence of Mullerian structures. hybridisation times were one hour for Hybond N Testicular biopsy showed seminiferous tubules, and three hours for N+. Hybridisation was over- hyalinisation, and fibrosis. night. Autoradiographs were developed overnight using Amersham Hyperfilm MP.

SPORADIC CASES Case 3 was 2 years old. The karyotype was 46,XX in LABELLING OF PROBES blood lymphocytes (G and C banding) and he has Probes SRY and pMF-1, which detects the ZFY been reared as a male. There was perineal hypospa- gene, were kindly provided by Dr Peter Goodfellow. dias, bilateral cryptorchidism, and absence of Miil- The plasmids were grown in E coli strain RR1 and lerian structures. Testicular biopsy showed semini- purified using Qiagen columns as recommended by ferous tubules and Sertoli cells. the manufacturer (Hybaid). Insert DNA was cut Case 4 was 4 years old. The karyotype was 46,XX with the appropriate restriction enzymes, separated in blood lymphocytes (G and C banding) and he has from vector DNA in a 1% agarose gel, and electro- been reared as a male. There was normal male eluted; 100 ng of insert was used in a random hexa- external genitalia with right cryptorchidism and nucleotide labelling reaction (Amersham) with 32P_

absence of Mullerian tubules. dCTP. copyright. Case 5 was 13 years old at the time of diagnosis. The karyotype was 46,XX and she was negative for Y centromeric specific probe Y-97 and probe Y190. PCR She has been reared as a female. There was hyper- Primers specific for the X and Y chromosomal trophy of the phallus, a right ovotestis, a left ovary, sequences and a primer for the pseudoautosomal bilateral fallopian tubes, a uterus, and a vagina. region were provided by Dr Peter Goodfellow and Ovarian tissue with stroma follicles and ova was their sequences are given in Ellis et al.10 Amplifica-

present as well as testis tissue with seminiferous tion was performed using a Techne PHC-2 block http://jmg.bmj.com/ tubules. The left ovary was considered normal and with 30 cycles at 94°C for one minute, 54'C for one was left in its place. The ovotestis was removed. The minute, and 72°C for one minute; 500 ng DNA was patient underwent normal puberty and four preg- used per reaction, with one unit of Amersham Taq nancies. The first pregnancy ended at 6 months with polymerase in manufacturer's buffer. All three a stillbirth of undefined sex. Then she had two primers were used in each reaction. Products were normal sons with normal 46,XY . The separated in a 2% agarose gel in TBE buffer and last pregnancy was continuing normally at the last stained with ethidium bromide. medical visit at the age of 27. on September 27, 2021 by guest. Protected Case 6 was 4 years old. The karyotype was nor- mal, 46,XY (G and C banding) and she has been Results reared as a female. There was normal external genit- The three XX males and two true hermaphrodites alia, bilateral fallopian tubes, a uterus, a vagina, and produced a female pattern of bands using the ZFY bilateral streak gonads. probe. The XY female showed the same pattern as a normal male. Fig 1 shows the results obtained using the ZFY probe. Controls were a normal male and SOUTHERN BLOTTING female and a male with a 46,Y,t(X;Y)(Xp22.3;Yql 1) DNA was extracted using the method of Kunkel et karyotype. al.8 Restriction enzymes were used as recommended Fig 2 illustrates the amplification products using by the manufacturer (Anglian). One percent agarose primers for the pseudoautosomal boundary. Those gels were made up in TBE buffer (electrophoresis samples which gave a female pattern with ZFY was carried out in the same buffer) and DNA was produced no bands with the pseudoautosomal transferred from the gel to nylon membranes using primers, while the XY female was positive with the method of Southern.9 Either Hybond N or PCR. Thus, the XX males and true hermaphrodites J Med Genet: first published as 10.1136/jmg.28.9.591 on 1 September 1991. Downloaded from

Use of probes for ZFY, SRY, Y pseudoautosomal boundary in XX males, XX true hermaphrodites, and XYfemale 593

male group that comprises a third of the cases studied up to now.'7 This category usually has variable degrees of hypospadias and gynaecomas- tia.620 True hermaphroditism in humans shows genoty- pic heterogeneity. In 60% of cases the karyotype was 46,XX and in 12% 46,XY; 13% were chimeras 46,XX/46,XY and the remainder were mosaics with normal or abnormal Y .2122 At first sight, this picture suggests that either the XX cases have some Y chromosome material, or that in most of the cases the abnormality in the differentiation of the bipotential gonad occurs at a stage after expres- sion of the putative TDF gene. It is interesting to note that in the structural abnormalities of the Y chromosome with or without a 45,X lineage, the patients usually develop dysgenetic testes23 instead of ovotestes. -;w In families where XX males and XX true herm- 2 3 4 5 6 7 8 aphrodites occur as sibs,717 or in families where sibs Figure 1 Southern blot of EcoRI digests probed with exhibit the XX male condition and abnormal geni- PMF.Ii (detects ZFY gene). Track (1) normal male, talia,20 subjects have mostly been negative for Y (2) XX male, case 4, (3) XYfemale, case 6, (4) XX chromosome specific probes. The isolated cases of Y male, casre 3, (5) 46,,t(X;7Y) male, (6) XX true negative XX males usually have ambiguous genitalia hermaph? (8) XX true hermaphrodite, case 5. The additional band in and this has been taken as evidence for a common track 3 iss a partial digest and was not apparent in this origin with XX true hermaphrodites.720 o?n sample other blots. To date, only two XX true hermaphrodite copyright. patients showing hybridisation with Y chromosome material have been reported by Palmer et all and Jager et al.24 The patient described by Palmer et all gave th4 e same bands as normal when ana- had an XX male brother with hypospadias. Both sibs lysed writh ZFY and pseudoautosomal probes. To were positive for the Y specific boundary sequence' determi.ne whether there had been a small amount of and the SRY gene. Y chronnosomal DNA transferred to the XX males, Our familial cases, one XX true hermaphrodite or deletoed from the XY female, the SRY probe was and an XX brother, showed no hybridisation with http://jmg.bmj.com/ used on HindIII digests of DNA. The results are either of the two proposed TDF genes (SRY or shown iin fig 3. Once again, the XX males and true ZFY), which agrees with previous reports2025 for the hermap]hrodites were negative for the SRY probe familial or sporadic cases of XX true hermaphrod- and the XY female gave the same band pattern as the ites. Our results, together with the family described male co: ntrols. by Palmer et al,' imply that even in the familial cases the two conditions are heterogeneous with respect to the presence of Y chromosome material. Mittwoch26 proposed that the Y chromosome on September 27, 2021 by guest. Protected Discus! sion DNA sequences concerned with 'testis determina- The present study showed absence of the Y specific tion' may act by enhancing cell division in the boundairy sequence and the SRY and ZFY genes in relevant gonadal cells, thus accelerating gonadal two spolradic XX males, one sporadic true hermaph- development. On the assumption that testes need to rodite, amd two sibs, one XX male and one XX true differentiate early, the Y chromosome could thus hermap]hrodite. The same Y sequences were present function to minimise the chance element in XY in one )CY female. fetuses of the gonad entering the ovarian pathway The Ihypothesis of an X;Y translocation in the and to maximise the probability of their developing paternal , proposed by Therkelsen" in 1964 as males. The proposition does not exclude the and Ferlguson Smith'2 in 1966, as the origin for some presence of a Y directive gene, the best candidate XX mal[es has been largely confirmed,'3-'8 with the being the SRY gene, functioning as the first switch high rat:e of recombination in the pseudoautosomal event in normal males and absent in XX normal region p'redisposing to unequal crossover and trans- females. locationS.9Unlike these cases, the XX male patients Among those patients who are Y negative XX in the present study belong to the Y negative XX males and XX true hermaphrodites, there may be J Med Genet: first published as 10.1136/jmg.28.9.591 on 1 September 1991. Downloaded from

594 Pereira, Almeida, Gunha, Patton, Taylor, J7effery

Figure 2 PCR amplification across the X and Y pseudoautosomal boundaries. Track (1) negative control, (2) normal female, (3) normal male, (4) 46, Y,t(X;Y) male, (5) normal male, (6) XX male, .. ... (7) XX male, (8) XX male, case 2, (9) blank, (10) XX true hermaphrodite, case 1, sib of case 2, (11) XX true hermaphrodite, case 5, (12) XYfemale, case 6, (13) negative control, (14) 1 kb ladder. Primer sequences are given in reference 10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 activation of a mechanism downstream in the path- essential for testis determination. These are very way from the TDF gene which leads to the first rare cases, however, where a mutation in the pro- switch of Sertoli cell differentiation. posed pathway controlled by the product of the SRY From the familial cases presented here and else- gene may have allowed testis development in the where,717 it is apparent that the same mechanism absence of that gene product. In normal males, the that can induce complete testis formation in an XX SRY gene seems likely to be the initial switch in the male is not necessarily enough to differentiate all the process leading to the production of testis. Demon- indifferent gonad cells into one testis in the XX true stration of this gene in those cases of XX males with hermaphrodites. Which endpoint is reached seems known translocation of Y material will increase the to be a matter of chance or the result of action on the probability that SRY is indeed TDF. Sequence embryonic cells of one or more as yet unidentified analysis of the DNA from XY females who are factor(s). positive for SRY, as in the case presented here and In the cases presented here and by Palmer et al,l those of Ferguson-Smith et al,4 should show copyright. there is a variation in the gonadal differentiation. whether these subjects have an inactive gene or The Y positive hermaphrodite described by Palmer perhaps a mutation elsewhere in the pathway of et all had bilateral ovotestes. Our familial cases had gonadal differentiation. In this respect, it is of inter- one fully developed testis and one ovotestis, while est that two XY females have recently been reported our sporadic case of true hermaphroditism had one as showing mutations in the SRY gene.33 Elucida- fully developed ovary with an ovotestis. tion of the structure of the SRY gene product and, At least 11 XY female patients have been de- from that, its possible mode of action, will provide scribed with deletions including the TDF region of more information on the starting point in this path- http://jmg.bmj.com/ the Y chromosome.'627-32 However, the XY female way. studied here did not show deletions of the Y chromosome, including SRY, as has also been de- We would like to thank Dr Peter Goodfellow's scribed in other cases.4 The presence of the SRY group for probes, advice, and encouragement, es- gene in an XY female obviously does not show that pecially Dr Andrew Sinclair. We gratefully acknow- the gene is functional; there could be microdeletions ledge support from CAPES (Postgraduate Educa- or point mutations in these subjects leading to a lack tion Federal Agency), Brazil for Dr Pereira. We on September 27, 2021 by guest. Protected of gene product or an inactive protein. thank Dr Ian Young (Leicester Royal Infirmary) for The absence of the SRY gene in XX males and blood samples from the XY female and Professor XX true hermaphrodites shows that this gene is not Ursula Mittwoch (Department of Anatomy, Queen

Figure 3 Southern blot of HindIII digests probed with SR Y cDNA. Tracks I to 8 are as forfig 1. Track 9 is a normal male, track 10 a normalfemale.

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Use of probes for ZFY, SR Y, Y pseudoautosomal boundary in XX males, XX true hermaphrodites, and XYfemale 595

17 de la Chapelle A. The Y-chromosomal and autosomal testis- Mary and Westfield College) for helpful advice on the determining genes. Development 1987;1O1(suppl):33-8. manuscript. 18 Affara NA, Ferguson-Smith MA, Tolmie J, et al. Variable transfer of Y-specific sequences in XX males. Nucleic Acids Res 1986;14:5375-87. 19 Weissenbach J, Le Villiers J, Petit C, Rouyer F, Simmler MC. 1 Palmer MS, Sinclair AH, Berta D, et al. Genetic evidence that Normal and abnormal interchanges between the X and Y ZFY is not the testis-determining factor. Nature 1989; chromosome. Development 1987;101(suppl):67-74. 342:937-9. 20 Abbas NE, Toublanc JE, Boucekkine C, et al. A possible 2 Sinclair AH, Berta P, Palmer MS, et al. A gene from the human common origin of Y-negative human XX males and XX true sex-determining region encodes a protein with homology to a hermaphrodites. Hum Genet 1990;84:356-60. conserved DNA-binding motif. Nature 1990;345:240-4. 21 Polani PE. Hormonal and clinical aspects of hermaphroditism 3 Gubbay J, Collignon J, Koopman P, et al. A gene mapping to and the testicular feminizing syndrome in man. Philos Trans sex-determining region of the mouse Y chromosome is a R Soc (Lond) (B) 1970;259:187-204. member of a novel family of embryonically expressed genes. Nature 1990;346:245-50. 22 Simpson JL. True hermaphroditism: etiology and phenotypic 4 Ferguson-Smith MA, North MA, Affara NA, Briggs H. The considerations. Sex differentiation and chromosomal abnor- secret of sex. Lancet 1990;336:809-10. malities. Birth Defects 1978;XIV(6):9-35. 5 Page DC, Fisher EM, McGillivray B, Brown LG. Additional 23 Daniel A, Lyons N, Casey JH, Gras L. Two dicentric isoch- deletion in sex-determining region of human Y chromosome romes, one without the Yq heterochromatic segment. Review resolves paradox of 46X,t(Y;22) female. Nature 1990; of the Y isochromes. Hum Genet 1980;54:31-9. 346:279-81. 24 Jager R, Ebensperger C, Fraccaro M, Steinbach P. A ZFY- 6 Ferguson-Smith MA, Cooke A, Affara NA, Boyd E, Tolmie JL. negative 46,XX true hermaphrodite is positive for the Y Genotype- correlations in XX males and their pseudoautosomal boundary. Hum Genet 1990;85:666-9. bearing on current theories of sex determination. Hum Genet 25 Damiani D, Billerbeck AEC, Goldberg ACK, Setian N, 1990;84: 198-202. Fellous M, Kalil J. Investigation of the ZFY gene in XX 7 Abbas N, Bouceckine C, Moreira-Filho CA, Ternes Pereira E, true hermaphroditism and Swyer syndrome. Hum Genet Cabral de Almeda JC, Fellous M. Familial cases of XX males: 1990;85:85-8. argument for a common origin of Y negative 46,XX male and 26 Mittwoch U. Sex, growth and chance. Nature 1990;344:389-90. true hermaphrodites. Cytogenet Cell Genet 1989;51:948. 27 Boyd E, Cooke A, Jamieson D, Kwok K, Mitchell N, 8 Kunkel LM, Smith KD, Boyer SH, et al. Analysis of human Snadden L. Mapping the testis determinants by an analysis Y-chromosome specific reiterated DNA in chromosome of Y-specific sequences in males with apparent XX and XO variants. Proc Natl Acad Sci USA 1977;74:1245-9. karyotypes and females with XY karyotypes. Nucleic Acids 9 Southern EM. Detection of specific sequences among DNA Res 1987;15:7325-42. fragments separated by gel electrophoresis. Mol Biol 28 Disteche CM, Casanova M, Saal H, et al. Small deletions of the 1975;98:503-1 7. short arm of the Y chromosome in 46,XY females. Proc Natl 10 Ellis N, Kidd J, Goodfellow PJ, Kidd K, Goodfellow P. Strong Acad Sci USA 1986;83:7841-4. linkage disequilibrium between the XY274 polymorphism

29 Magenis RE, Tochen NL, Holahan KP, Carey T, Allen L, copyright. and the pseudoautosomal boundary. Am Hum Genet Brown MG. resulting from partial deletion 1 990;46:950-5. of Y chromosome short arm: localisation of male determin- 11 Therkelson AJ. Sterile male with chromosomal constitution, ants. J Pediatr 1984;105:916-19. 46,XX. 1964;3:207-18. 30 Rosenfeld RG, Luzzatti L, Hintz RL, Miller OJ, Koo GC, 12 Ferguson-Smith MA. X-Y chromosomal interchange in the Wachtel SS. Sexual and somatic determinants of the human Y aetiology of true hermaphrodites and XX Klinefelter's syn- chromosome: studies in a 46 XYp - phenotypic female. Am J drome. Lancet 1966;i:475-6. Hum Genet 1979;31:458-77. 13 Magenis RE, Casanova M, Fellous M, Olson S, Sheeny R. Further cytologic evidence for Xp-Yp translocations in XX 31 Le Villiers J, Quack B, Weissenbach J, Petit C. Exchange of males using in situ hybridization with Y-derived probe. Hum terminal portions of X and Y chromosomal short arms in Genet 1978;75:228-33. human XY females. Proc Natl Acad Sci USA 1989;86:2296-

14 Page DC, de la Chapelle A, Weissenbach J. Chromosome 300. http://jmg.bmj.com/ Y-specific DNA in related human XX males. Nature 1985; 32 Blagowidow N, Page DC, Huff D, Mennuti MT. Ulrich- 315:224-7. Turner syndrome in one XY female fetus with deletion of the 15 Ferguson-Smith MA, Affara NA, Magenis RE. Ordering of sex-determining portion of the Y chromosome. Am J Med Y-specific sequences by deletion mapping and analysis of Genet 1989;34:159-62. X-Y interchange in males and females. Development 33 Berta P, Hawkins JR, Sinclair AH, et al. Genetic evidence 1987;101(suppl):41-50. equating SRY and the testis determining factor. Nature 16 Muller U, Donlon T, Schmid M, et al. Deletion mapping of the 1990;348:448-50. testis determining locus with DNA probes in 46,XX males 34 Jager RJ, Anvret M, Hall K, Scherer G. A human XY female and in 46,XY and 46,X,dic(Y) females. Nucleic Acids Res with a frame shift mutation in the candidate testis-determin- 1986;14:6489-504. ing gene SRY. Nature 1990;348:425-54. on September 27, 2021 by guest. Protected