Chimerism in Black Southern African Patients with True Hermaphroditism 46,XX/47XY,+21 and 46,XX/46,XY

Authors

  • M. Ramsay,

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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  • W. Pfaffenzeller,

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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  • E. Kotze,

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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  • L. Bhengu,

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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  • F. Essop,

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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  • T. De Ravel

    1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
    2. Centre for Human Genetics, UZ Gasthuisberg, Leuven, Belgium
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Address for correspondence: Michele Ramsay, Division of Human Genetics, National Health Laboratory Service, P.O. Box 1038, Johannesburg 2000, South Africa. Voice: +27-11-489-9214; Fax: +27-11-489-9226. michele.ramsay@nhls.ac.za

Abstract

True hermaphroditism is defined by the presence of both testicular and ovarian tissue in an individual. True hermaphrodites usually present at birth with ambiguous genitalia, and subsequent invasive investigations are needed to confirm the diagnosis. Several large cohorts of black South Africans with true hermaphroditism have been described, and by far the majority of those investigated had a 46,XX karyotype, with absence of the SRY sequence. This paper represents the first report of the molecular investigation of mosiacism/chimerism as the cause of hermaphroditism in black southern African patients. It is the second report worldwide of a 46,XX/47,XY,+21 chimera, with the first described in a Japanese infant in 1994. Case 1 in the present study is a child who is a 46,XX/47,XY,+21 tetragametic chimera. Molecular studies revealed two paternal and two maternal alleles at four of ten STR loci investigated and three alleles at four of these loci. The young boy exhibited no features of Down syndrome, other than a unilateral single palmar crease. Cases 2 and 3 both have a 46,XX/46,XY karyotype. Chimerism is supported by molecular analysis in Case 2, and molecular studies were not done for Case 3.

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