SHORT COMMUNICATION Mapping around the Xql 3.1 Breakpoints of Two X/A Translocations in Hypohidrotic Ectodermal Dysplasia (EDA) Female Patients BEATRICE PLOUGASTEL, *'1 PHILIPPE COUILLIN,I VI~RONIQUE BLANQUET,* ERIC LE GUERN,-I- EGBERT BAKKER,:I: CATHERINE TURLEAU,* JEAN DE GROUCHY,* AND NICOLE CR/=AU-GOLDBERG *'2
*U173 INSERM, HGpital Necker Enfants Malades, 149 rue de 5~vres, 75743 Paris Cedex 15, France; tU73 INSERM, Gdndtique et Patho/ogie Foetale, Chateau de Longchamp, Bois de Boulogne, 75016, Paris, France; and SDepartment of Human Genetics, Sylvius Laboratory, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands Received February 13, 1992; revised May 26, 1992 somatic cell hybrids (AnlyRAG) for gene mapping purposes. Assuming that no rearrangement has occurred in the hybrid cell line AnlyRAG (containing the der(9)), DXS159 would be proximal to the disorder, and PGK1 distal (13).
C e l l u l a r h y b r i d s w e r e o b t a i n e d f r o m a t(X; 12) i d e n t i fied in a f e m a l e p a t i e n t w i t h h y p o h i d r o t i c e c t o d e r m a l dysplasia (EDA). This rearrangement had the same X q l 3 . 1 c y t o g e n e t i c b r e a k p o i n t as a t ( X ; 9 ) f o u n d in a previously observed EDA patient. A comparative analysis of these two rearrangements with nine probes was p e r f o r m e d at t h e m o l e c u l a r l e v e l . T h e s e p r o b e s c o u l d define three subregions: three are proximal, two are distal, and four are between the two breakpoints. These last probes should prove useful for cloning the gene.
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© 1992 Academic Press, Inc.
Hypohidrotic ectodermal dysplasia (EDA) is a rare Xlinked disorder, in which ectodermal derivatives are variously affected: diminution or absence of eccrine sweat glands, oligodontia and peg-shaped teeth, and thin and sparse hair. Because of severe illness in early childhood, recurrent respiratory infections, and nearly 30% mortality, prenatal diagnosis and carrier detection are important goals. Heterozygous females usually show only mild or no clinical expression due to random chromosome X inactivation (2). Thus, accurate carrier detection in at-risk females was problematic. Prenatal diagnosis can be performed by electron microscopy on fetal skin biopsies obtained under fetoscopy at the 20th week of gestation (1). The accuracy of this procedure, however, has not been validated. A study at the molecular genetic level seems to be the best alternative approach. Linkage with EDA has been shown successively with the polymorphic locus DXYS1 (9), then with the DXS14 probe ( X p l l - c e n ) located proximal to DXYS1 (3), and finally with the polymorphic loci DXS159 ( X q l l - q l 2 ) and PGK1 (6). A female manifesting EDA and who had a de novo t(X;9) was reported in 1973 (HGM1). The X breakpoint was shown to be in Xql3.1 (13). The corresponding cell line, referred to as the Anly line, has been used extensively by a number of investigators in the construction of 1Present address: URA620 CNRS, Institut Curie, Paris, France. 2To whom correspondenceshould be addressed.
G54
StlO
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FIG. 1. (A) Southern blot of HindIII-digested DNA (1) t(X;12) patient, (2) her mother, (3) her father, (4) hamster cell line, (5) mouse cell line, (6) AnlyRAG,(7) C.CARllT42, (8) C.CAR1,hybridized successively with st72 (DXS61), G54 (DXS224), and stl0 (DXS55). (B) Ethidium bromide-stained gel corresponding to the Southern blot shown in A.
523
GENOMICS 14, 523-525 (1992)
0888-7543/92$5.00 Copyright© 1992by AcademicPress, Inc. All rights of reproductionin any form reserved.
524
SHORT COMMUNICATION R CARl IT 42 MIC 2
Xq11 EDA
I--
Xq13
cpX289
st72
DXSI59
DXS61
cX37. I DXSI53
HPRT
G54 DXS224
cpX23
cpX58
DXSI32 DXS 469
CCGI
ST10
PGKI
CCGI
DXS55
PGKI
P
MIC 5, F814 -'1~
Anly RAG
C CAR I R CAR 14
Oer(9)
Der(l 2)
X CHROMOSOME
t(X;9)
Der(X)
t(X;12)
FIG. 2. Schematic representation of the X content of the t(X;9) and t(X;12) corresponding hybrids: AnlyRAG containing the der(9), C.CAR1 containing the der(12), and C.CARllT42 containing the der(X) of the t(X;12). Localization of nine probes into the three subregions is defined by the two breakpoints.
A second case of a de novo t(X/A) in a female EDA patient was reported by Turleau et al. (12). The karyotype revealed a t(X;12)(q13;q24). Cytogenetic analysis showed that the X breakpoint was apparently the same as that in the previously reported t(X;9). I n situ hybridization confirmed that the breakpoint was also located between DXS159 and PGK1 (data not shown). To compare at the molecular level the X breakpoints TABLE 1 Probes and Loci Mapped in the Hybrids Probe
Locus
Source
cpX289
DXS159
M . H . Hofker, P. Pearson
pHPGK
PGK1
A.M. Michelson
stl0
DXS55
J . L . Mandel
st72
DXS61
J, L. Mandel
G54
DXS224
J . L . Mandel
pUC462
CCG1
T. Nishimoto
cpX23
DXS132
M . H . Hofker, P. Pearson
cpX58
DXS469
M . H . Hofker, P. Pearson
cX37.1
DXS153
M . H . Hofker, P. Pearson
F814
DXS152 + FSC
J . L . Mandel
Note. The probes are referenced in H G M l l (Cytogenet. Cell Genet. 1991, in press).
of the two translocations, hybrid cell lines from the t(X;12) were compared with the AnlyRAG cell line. To improve the map, hybrids containing either the der(X) or the der(12) were obtained following the strategy detailed in (4). The t(X;12) lymphoblastoid cell line was fused with two different HPRT-deficient rodent cell lines, CHcl3S Chinese hamster or RAG mouse, giving rise to C-CARn and R-CARn hybrids, respectively. Hybrids segregating the der(12) H P R T + chromosome were directly obtained by azaserine selection and subcloning. Hybrids segregating the der(X) H P R T - chromosome were obtained after 6-thioguanine backselection and subcloning. For both cases, screenings were performed mainly by indirect immunofluorescence (IIF), using monoclonal antibodies against antigens encoded by the MIC2 (5) and MIC5 (7) loci that are located within the Xp and the Xq terminal regions, respectively, and secondarily by Southern blotting, using the F814 probe (Fig. 2). Hybrids C-CAR1 and R-CAR14 on the one hand and R - C A R l l T 4 2 on the other were fully characterized by Southern blotting, IIF, and cytogenetic analysis, showing that the hybrids segregated the der(12) and the der(X), respectively, with no evidence of secondary rearrangement. Using the F814 probe, which reveals an informative T a q I polymorphism in the family of the patient carrying the t(X;12), we determined that the de novo translocation was of paternal origin. Nine probes (Table 1) of the X q l 2 - q l 3 region were localized with regard to the two breakpoints. Molecular analysis of hybrids C-CAR1, R-CAR14, R - C A R l l T 4 2 ,
525
SHORT COMMUNICATION
and AnlyRAG showed that the region containing the nine probes could be divided into three subregions (Figs. 1 and 2): (A) a subregion distal to the t(X;9) breakpoint with three probes, stl0 (DXS55), CCG1, and PGK1, that give a positive signal with hybrid AnlyRAG carrying the der(9) chromosome and hybrid C-CAR1 carrying the der(12) chromosome; (B) a subregion proximal to the t(X;12) breakpoint with two probes, DXS159 and st72 (DXS61), that give a positive signal with RCARllT42, the hybrid cell line carrying the der(X) derived from the t(X;12), and a negative signal with CCAR1, the hybrid cell line carrying the other derivative; (C) a subregion localized between the two breakpoints with four probes cX37.1 (DXS153), G54 (DXS224), cpX23 (DXS132), and cpX58 (DXS469). These probes reveal a positive signal with C-CAR1 and a negative signal with AnlyRAG. None of the probes detect either rearrangement or deletion in the hybrids containing either the der(12) or the der(X), after conventional Southern blotting with the enzymes EcoRI, TaqI, and HindIII (data not shown). In the case of the t(X;9) patient, the study of a hybrid containing the other derivative der(X) would allow us to confirm or exclude a molecular deletion. CCG1 and PGK1 have recently been located distal to [DXS159, DXS132, DXS153] (8). The comparison of the two translocations shows that DXS159 is proximal to DXS153 and DXS132, which is compatible with the genetic map of this region (10). Probe DXS55 is also found distal to DXS224 (11). The two translocations associated with EDA may have disrupted the gene involved. Molecular analysis of the two translocations indicates that the two Xql3.1 breakpoints are different. The assignment of four probes between the two breakpoints is compatible with the hypothesis that these probes are indeed within or near the gene. Their identification will prove very useful for an approach toward the cloning of the EDA gene. Among these probes, two are polymorphic markers, DXS153 (BstEII) and DXS132 (DraI), which should improve genetic counseling accuracy, compared to the more distant markers DXS159 and PGK1 (14). ACKNOWLEDGMENTS We are grateful to Professor Niaudet, who referred the t(X;12) patient; to Professor A. Bout, who transformed the lymphocytes derived from the t(X;12) patient and her mother; to Dr. K.-H. Grzeschik for the AnlyRAG line; to Professor J-L. Mandel for probes st10, st72, and G54; to Drs. M. H. Hofker and P. L. Pearson for probes cpX23, cpX58, DXS159, and cX37.1; to Dr. Michelson for PGK1; to Dr. T. Nishi-
moto for CCG1; and to Dr. P. Goodfellow for the monoclonal antibodies R1 and 12E7. REFERENCES 1. Arnold, M-L., Rauskolb, R., Anton-Lamprecht, I., Shinzil, A., and Schwid, W. (1984). Prenatal diagnosis of anhidrotic ectodermal dysplasia. Prenat. Diagn. 4:85-98. 2. Clarke, A., Philipps, D. I. M., Brown, R., and Harper, P-S. (1987). Clinical aspect of X-linked hypohidrotic ectodermal dysplasia. Arch. Dis. Child. 62:989-996. 3. Clarke, A., Sarfarazi, M., Roberts, K., and Harper, P-S. (1987). X-linked hypohidrotic ectodermal dysplasia: DNA probe linkage analysis and gene localization. Hum. Genet. 75:378-380. 4. Couillin, P., Le Guern, E., Ravise, N., Grisard, M-C., Oostra, B.A., and Bout, A. (1990). Strategy for constructing somatic hybrids isolating the two derivative chromosomes in X/autosome translocations: Application to a female t(X;5) with Hunter syndrome. Ann. Gdndt. 33:196-207. 5. Goodfellow, P. J., Darling, S. M., Thomas, N. S., and Goodfellow, P. N. (1986). A pseudoautosomal gene in man. Science 234:740743. 6. Hanauer, A., Alembik, Y., Formiga, L., Gilgenkrantz, S., and Mandel, J-L. (1986). Genetic mapping of anhidrotic ectodermal dysplasia: DXS159, a closely linked proximal marker. Hum. Genet. 80:177-180. 7. Hope, R-M., Goss, S., Solomon, E., Ropers, H-H., Banting, G., and Goodfellow, P-N. (1987). Localisation of MIC5 to the region between HPRT and G6PD on the human X chromosome. Ann. Hum. Genet. 51:1-7. 8. Lafreni~re, R. G., Brown, C. J., Powers, V. E., Carrel, L., Davies, K. E., Barker, D. F., and Willard, H. F. (1991). Physical mapping of 60 DNA markers in the p21.1-q21.3 region of the human X chromosome. Genomics 11:352-363. 9. Mac Dermot, K-D., Winter, R-M., and Malcolm, S. (1988). Gene localisation of X-linked hypohidrotic ectodermal dysplasia (C-ST syndrome). Hum. Genet. 74:172-173. 10. Mahtani, I. M. M., Lafreni~re, R. G., Kruse, T. A., and Willard, H.F. (1991). An 18-locus linkage map of the pericentromeric region of the human X chromosome: Genetic framework for mapping X-linked disorders. Genomics 10:849-857. 11. Oberl~, I., Camerino, G., Kloepfer, C., Moisan, J-P., Grzeschik, K. H., Hellkuhl, B., Hors-Cayla, M. C., Van Cong, N., Weil, D., and Mandel, J-L. (1986). Characterization of a set of X-linked sequences of a panel of somatic cell hybrids useful for the regional mapping of the human X chromosome. Hum. Genet. 72:43-49. 12. Turleau, C., Niaudet, P., Cabanis, M-O., Plessis, G., Cau, D., and Grouchy, J. de (1989). X-linked hypohidrotic ectodermal dysplasia and t(X;12) in a female. Clin. Genet. 35:462-466. 13. Zonana, J., Roberts, S., Thomas, N. S. T., and Harper P-S. (1988). Recognition and reanalysis of a cell line from a manifestating female with X-linked hypohidrotic ectodermal dysplasia. J. Med. Genet. 25:383-386. 14. Zonana, J., Schinzel, A., Upadhaya, M., Thomas, N. S. T., Anton-Lamprecht, I., and Harper, P-S. (1990). Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia by linkage analysis. Am. J. Hum. Genet. 35:132-135.
*U173 INSERM, HGpital Necker Enfants Malades, 149 rue de 5~vres, 75743 Paris Cedex 15, France; tU73 INSERM, Gdndtique et Patho/ogie Foetale, Chateau de Longchamp, Bois de Boulogne, 75016, Paris, France; and SDepartment of Human Genetics, Sylvius Laboratory, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands Received February 13, 1992; revised May 26, 1992 somatic cell hybrids (AnlyRAG) for gene mapping purposes. Assuming that no rearrangement has occurred in the hybrid cell line AnlyRAG (containing the der(9)), DXS159 would be proximal to the disorder, and PGK1 distal (13).
C e l l u l a r h y b r i d s w e r e o b t a i n e d f r o m a t(X; 12) i d e n t i fied in a f e m a l e p a t i e n t w i t h h y p o h i d r o t i c e c t o d e r m a l dysplasia (EDA). This rearrangement had the same X q l 3 . 1 c y t o g e n e t i c b r e a k p o i n t as a t ( X ; 9 ) f o u n d in a previously observed EDA patient. A comparative analysis of these two rearrangements with nine probes was p e r f o r m e d at t h e m o l e c u l a r l e v e l . T h e s e p r o b e s c o u l d define three subregions: three are proximal, two are distal, and four are between the two breakpoints. These last probes should prove useful for cloning the gene.
A
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4
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7 8
St72
© 1992 Academic Press, Inc.
Hypohidrotic ectodermal dysplasia (EDA) is a rare Xlinked disorder, in which ectodermal derivatives are variously affected: diminution or absence of eccrine sweat glands, oligodontia and peg-shaped teeth, and thin and sparse hair. Because of severe illness in early childhood, recurrent respiratory infections, and nearly 30% mortality, prenatal diagnosis and carrier detection are important goals. Heterozygous females usually show only mild or no clinical expression due to random chromosome X inactivation (2). Thus, accurate carrier detection in at-risk females was problematic. Prenatal diagnosis can be performed by electron microscopy on fetal skin biopsies obtained under fetoscopy at the 20th week of gestation (1). The accuracy of this procedure, however, has not been validated. A study at the molecular genetic level seems to be the best alternative approach. Linkage with EDA has been shown successively with the polymorphic locus DXYS1 (9), then with the DXS14 probe ( X p l l - c e n ) located proximal to DXYS1 (3), and finally with the polymorphic loci DXS159 ( X q l l - q l 2 ) and PGK1 (6). A female manifesting EDA and who had a de novo t(X;9) was reported in 1973 (HGM1). The X breakpoint was shown to be in Xql3.1 (13). The corresponding cell line, referred to as the Anly line, has been used extensively by a number of investigators in the construction of 1Present address: URA620 CNRS, Institut Curie, Paris, France. 2To whom correspondenceshould be addressed.
G54
StlO
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FIG. 1. (A) Southern blot of HindIII-digested DNA (1) t(X;12) patient, (2) her mother, (3) her father, (4) hamster cell line, (5) mouse cell line, (6) AnlyRAG,(7) C.CARllT42, (8) C.CAR1,hybridized successively with st72 (DXS61), G54 (DXS224), and stl0 (DXS55). (B) Ethidium bromide-stained gel corresponding to the Southern blot shown in A.
523
GENOMICS 14, 523-525 (1992)
0888-7543/92$5.00 Copyright© 1992by AcademicPress, Inc. All rights of reproductionin any form reserved.
524
SHORT COMMUNICATION R CARl IT 42 MIC 2
Xq11 EDA
I--
Xq13
cpX289
st72
DXSI59
DXS61
cX37. I DXSI53
HPRT
G54 DXS224
cpX23
cpX58
DXSI32 DXS 469
CCGI
ST10
PGKI
CCGI
DXS55
PGKI
P
MIC 5, F814 -'1~
Anly RAG
C CAR I R CAR 14
Oer(9)
Der(l 2)
X CHROMOSOME
t(X;9)
Der(X)
t(X;12)
FIG. 2. Schematic representation of the X content of the t(X;9) and t(X;12) corresponding hybrids: AnlyRAG containing the der(9), C.CAR1 containing the der(12), and C.CARllT42 containing the der(X) of the t(X;12). Localization of nine probes into the three subregions is defined by the two breakpoints.
A second case of a de novo t(X/A) in a female EDA patient was reported by Turleau et al. (12). The karyotype revealed a t(X;12)(q13;q24). Cytogenetic analysis showed that the X breakpoint was apparently the same as that in the previously reported t(X;9). I n situ hybridization confirmed that the breakpoint was also located between DXS159 and PGK1 (data not shown). To compare at the molecular level the X breakpoints TABLE 1 Probes and Loci Mapped in the Hybrids Probe
Locus
Source
cpX289
DXS159
M . H . Hofker, P. Pearson
pHPGK
PGK1
A.M. Michelson
stl0
DXS55
J . L . Mandel
st72
DXS61
J, L. Mandel
G54
DXS224
J . L . Mandel
pUC462
CCG1
T. Nishimoto
cpX23
DXS132
M . H . Hofker, P. Pearson
cpX58
DXS469
M . H . Hofker, P. Pearson
cX37.1
DXS153
M . H . Hofker, P. Pearson
F814
DXS152 + FSC
J . L . Mandel
Note. The probes are referenced in H G M l l (Cytogenet. Cell Genet. 1991, in press).
of the two translocations, hybrid cell lines from the t(X;12) were compared with the AnlyRAG cell line. To improve the map, hybrids containing either the der(X) or the der(12) were obtained following the strategy detailed in (4). The t(X;12) lymphoblastoid cell line was fused with two different HPRT-deficient rodent cell lines, CHcl3S Chinese hamster or RAG mouse, giving rise to C-CARn and R-CARn hybrids, respectively. Hybrids segregating the der(12) H P R T + chromosome were directly obtained by azaserine selection and subcloning. Hybrids segregating the der(X) H P R T - chromosome were obtained after 6-thioguanine backselection and subcloning. For both cases, screenings were performed mainly by indirect immunofluorescence (IIF), using monoclonal antibodies against antigens encoded by the MIC2 (5) and MIC5 (7) loci that are located within the Xp and the Xq terminal regions, respectively, and secondarily by Southern blotting, using the F814 probe (Fig. 2). Hybrids C-CAR1 and R-CAR14 on the one hand and R - C A R l l T 4 2 on the other were fully characterized by Southern blotting, IIF, and cytogenetic analysis, showing that the hybrids segregated the der(12) and the der(X), respectively, with no evidence of secondary rearrangement. Using the F814 probe, which reveals an informative T a q I polymorphism in the family of the patient carrying the t(X;12), we determined that the de novo translocation was of paternal origin. Nine probes (Table 1) of the X q l 2 - q l 3 region were localized with regard to the two breakpoints. Molecular analysis of hybrids C-CAR1, R-CAR14, R - C A R l l T 4 2 ,
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SHORT COMMUNICATION
and AnlyRAG showed that the region containing the nine probes could be divided into three subregions (Figs. 1 and 2): (A) a subregion distal to the t(X;9) breakpoint with three probes, stl0 (DXS55), CCG1, and PGK1, that give a positive signal with hybrid AnlyRAG carrying the der(9) chromosome and hybrid C-CAR1 carrying the der(12) chromosome; (B) a subregion proximal to the t(X;12) breakpoint with two probes, DXS159 and st72 (DXS61), that give a positive signal with RCARllT42, the hybrid cell line carrying the der(X) derived from the t(X;12), and a negative signal with CCAR1, the hybrid cell line carrying the other derivative; (C) a subregion localized between the two breakpoints with four probes cX37.1 (DXS153), G54 (DXS224), cpX23 (DXS132), and cpX58 (DXS469). These probes reveal a positive signal with C-CAR1 and a negative signal with AnlyRAG. None of the probes detect either rearrangement or deletion in the hybrids containing either the der(12) or the der(X), after conventional Southern blotting with the enzymes EcoRI, TaqI, and HindIII (data not shown). In the case of the t(X;9) patient, the study of a hybrid containing the other derivative der(X) would allow us to confirm or exclude a molecular deletion. CCG1 and PGK1 have recently been located distal to [DXS159, DXS132, DXS153] (8). The comparison of the two translocations shows that DXS159 is proximal to DXS153 and DXS132, which is compatible with the genetic map of this region (10). Probe DXS55 is also found distal to DXS224 (11). The two translocations associated with EDA may have disrupted the gene involved. Molecular analysis of the two translocations indicates that the two Xql3.1 breakpoints are different. The assignment of four probes between the two breakpoints is compatible with the hypothesis that these probes are indeed within or near the gene. Their identification will prove very useful for an approach toward the cloning of the EDA gene. Among these probes, two are polymorphic markers, DXS153 (BstEII) and DXS132 (DraI), which should improve genetic counseling accuracy, compared to the more distant markers DXS159 and PGK1 (14). ACKNOWLEDGMENTS We are grateful to Professor Niaudet, who referred the t(X;12) patient; to Professor A. Bout, who transformed the lymphocytes derived from the t(X;12) patient and her mother; to Dr. K.-H. Grzeschik for the AnlyRAG line; to Professor J-L. Mandel for probes st10, st72, and G54; to Drs. M. H. Hofker and P. L. Pearson for probes cpX23, cpX58, DXS159, and cX37.1; to Dr. Michelson for PGK1; to Dr. T. Nishi-
moto for CCG1; and to Dr. P. Goodfellow for the monoclonal antibodies R1 and 12E7. REFERENCES 1. Arnold, M-L., Rauskolb, R., Anton-Lamprecht, I., Shinzil, A., and Schwid, W. (1984). Prenatal diagnosis of anhidrotic ectodermal dysplasia. Prenat. Diagn. 4:85-98. 2. Clarke, A., Philipps, D. I. M., Brown, R., and Harper, P-S. (1987). Clinical aspect of X-linked hypohidrotic ectodermal dysplasia. Arch. Dis. Child. 62:989-996. 3. Clarke, A., Sarfarazi, M., Roberts, K., and Harper, P-S. (1987). X-linked hypohidrotic ectodermal dysplasia: DNA probe linkage analysis and gene localization. Hum. Genet. 75:378-380. 4. Couillin, P., Le Guern, E., Ravise, N., Grisard, M-C., Oostra, B.A., and Bout, A. (1990). Strategy for constructing somatic hybrids isolating the two derivative chromosomes in X/autosome translocations: Application to a female t(X;5) with Hunter syndrome. Ann. Gdndt. 33:196-207. 5. Goodfellow, P. J., Darling, S. M., Thomas, N. S., and Goodfellow, P. N. (1986). A pseudoautosomal gene in man. Science 234:740743. 6. Hanauer, A., Alembik, Y., Formiga, L., Gilgenkrantz, S., and Mandel, J-L. (1986). Genetic mapping of anhidrotic ectodermal dysplasia: DXS159, a closely linked proximal marker. Hum. Genet. 80:177-180. 7. Hope, R-M., Goss, S., Solomon, E., Ropers, H-H., Banting, G., and Goodfellow, P-N. (1987). Localisation of MIC5 to the region between HPRT and G6PD on the human X chromosome. Ann. Hum. Genet. 51:1-7. 8. Lafreni~re, R. G., Brown, C. J., Powers, V. E., Carrel, L., Davies, K. E., Barker, D. F., and Willard, H. F. (1991). Physical mapping of 60 DNA markers in the p21.1-q21.3 region of the human X chromosome. Genomics 11:352-363. 9. Mac Dermot, K-D., Winter, R-M., and Malcolm, S. (1988). Gene localisation of X-linked hypohidrotic ectodermal dysplasia (C-ST syndrome). Hum. Genet. 74:172-173. 10. Mahtani, I. M. M., Lafreni~re, R. G., Kruse, T. A., and Willard, H.F. (1991). An 18-locus linkage map of the pericentromeric region of the human X chromosome: Genetic framework for mapping X-linked disorders. Genomics 10:849-857. 11. Oberl~, I., Camerino, G., Kloepfer, C., Moisan, J-P., Grzeschik, K. H., Hellkuhl, B., Hors-Cayla, M. C., Van Cong, N., Weil, D., and Mandel, J-L. (1986). Characterization of a set of X-linked sequences of a panel of somatic cell hybrids useful for the regional mapping of the human X chromosome. Hum. Genet. 72:43-49. 12. Turleau, C., Niaudet, P., Cabanis, M-O., Plessis, G., Cau, D., and Grouchy, J. de (1989). X-linked hypohidrotic ectodermal dysplasia and t(X;12) in a female. Clin. Genet. 35:462-466. 13. Zonana, J., Roberts, S., Thomas, N. S. T., and Harper P-S. (1988). Recognition and reanalysis of a cell line from a manifestating female with X-linked hypohidrotic ectodermal dysplasia. J. Med. Genet. 25:383-386. 14. Zonana, J., Schinzel, A., Upadhaya, M., Thomas, N. S. T., Anton-Lamprecht, I., and Harper, P-S. (1990). Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia by linkage analysis. Am. J. Hum. Genet. 35:132-135.
