Medicina (Kaunas) 2005; 41 (8): 633-640

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Human male sex determination and sexual differentiation: pathways, molecular interactions and genetic disorders

Laimutis Kučinskas, Walter Just1

Department of Biology, Kaunas University of Medicine, Lithuania, 1Department of Human Genetics, University of Ulm, Germany

Key words: male sex determination, sexual differentiation, intersexual conditions.

Summary. The complex mechanisms are responsible for male sex determination and differentiation. The steps of formation of the testes are dependent on a series of Y-linked, X-linked and autosomal genes actions and interactions. After formation of testes the gonads secrete hormones, which are essential for the formation of the male genitalia. Hormones are transcription regulators, which function by specific receptors. Ambiguous genitalia are result of disruption of genetic interaction. This review describes the mechanisms, which lead to differentiation of male sex and ways by which the determination and differentiation may be interrupted by naturally occurring mutations, causing different syndromes and diseases.

Correspondence to L. Kučinskas, Department of Biology, Kaunas University of Medicine, A. Mickevičiaus 9, 44307 Kaunas, Lithuania. E-mail:

Received 12 October 2004, accepted 25 July 2005