Urological andrology and reproductive medicine

Prof. Dr. med. Sabine Kliesch

During our daily clinical work, we meet patients with a variety of andrological symptoms. For continuous improvement of diagnostics and therapies our research is of major importance. In close cooperation with natural scientists from the Institute of Reproductive and Regenerative Medicine we carry out translational projects which enables us to directly transfer results from basic research into the clinic. In clinical studies we additionally record and evaluate a wide set of parameters in extensive databases and biosample repositories. Based on our research we can examinate results interdisciplinary and provide individualised therapies according to the current status of knowledge. Consequently, the andrological symptoms of our patients are the basis for our research activities.

  • Research focus

    • Fertility preservation: Protection of a person’s fertility by the use of cryo-conservation of sperm cells or germ cell tissues (among other things Androprotect - clinic and research)
    • Methods of sperm diagnostics and surgical sperm extraction, processing and their use for in vitro fertilisation
    • Long-term consequences of cancer treatment for male testicular and sexual function: defective erection and ejaculation, reduced fertility, hormone deficiency diseases
    • Male infertility

    At the moment, we closely cooperate in Clinical Research Unit (CRU) projects, research on testicular stem cells and sperm physiology.


  • Literature

    All publications of Sabine Kliesch are given here (Pubmed)


Endocrinological andrology

Prof. Dr. med. Michael Zitzmann
Study on effects of testosterone on:
hematopoeisis, insulin sensitivity, inflammation

Endocrinological Andrology combines patient care and research of male sex hormones, metabolic disorders, fertility and related genetics. Diagnostic tools as well as specific treatment protocols for various patient groups are developed and have been implented in various international guidelines.

  • Research focus

    • Androgen deficiency, testosterone substitution and effects on target tissues:
      • Metabolism
      • Inflammation
      • Bone tissue
      • Psychological aspects
      • Sexual function
    • Klinefelter Syndrome
      • Hypogonadism
      • Genetics and epigenetics
      • Fertility
    • Induction of fertility in male hypogonadism
    • Hormonal contraception in men
    • Post-Finasteride-Syndrome
    • The aging male



  • Literature

    All publications of Michael Zitzmann are given here (Pubmed)

    Selected literature:

    Zitzmann M, Aksglaede L, Corona G, Isidori AM, Juul A, T'Sjoen G, Kliesch S, D'Hauwers K, Toppari J, Słowikowska-Hilczer J, Tüttelmann F, Ferlin A. European academy of andrology guidelines on Klinefelter Syndrome Endorsing Organization: European Society of Endocrinology. Andrology. 2021 Jan;9(1):145-167. doi: 10.1111/andr.12909.

    Corona G, Goulis DG, Huhtaniemi I, Zitzmann M, Toppari J, Forti G, Vanderschueren D, Wu FC. European Academy of Andrology (EAA) guidelines on investigation, treatment and monitoring of functional hypogonadism in males: Endorsing organization: European Society of Endocrinology. Andrology. 2020 Sep;8(5):970-987. doi: 10.1111/andr.12770.

    Zitzmann M. Testosterone, mood, behaviour and quality of life. Andrology. 2020 Nov;8(6):1598-1605. doi: 10.1111/andr.12867.

    Zitzmann M, Bongers R, Werler S, Bogdanova N, Wistuba J, Kliesch S, Gromoll J, Tüttelmann F. Gene expression patterns in relation to the clinical phenotype in Klinefelter syndrome. J Clin Endocrinol Metab. 2015 Mar;100(3):E518-23. doi: 10.1210/jc.2014-2780.

    Zitzmann M, Faber S, Nieschlag E. Association of specific symptoms and metabolic risks with serum testosterone in older men. J Clin Endocrinol Metab. 2006 Nov;91(11):4335-43. doi: 10.1210/jc.2006-0401.

    Lanfranco F, Kamischke A, Zitzmann M, Nieschlag E. Klinefelter's syndrome. Lancet. 2004 Jul 17-23;364(9430):273-83. doi: 10.1016/S0140-6736(04)16678-6.

Paediatric and adolescent andrology

PD Dr. med. Julia Rohayem

The early diagnosis of reproductive dysfunction is a prerequisite for fertility inducing hormone therapy and/or fertility-preserving measures to enable future paternity.
The consultation “Jugend-Andrologie und Transitions-Endikrinologie” at the UKM is a bridging between paediatric and adolescent endocrinology and adult endocrinology and andrology.

Our research objective is analyzing the pathomechanisms fertility potential of boys with variations in puberty development or gender differentiation to deduce medical treatment recommendations.

Accordingly, the aim of our research is to analyze the pathomechanisms of fertility impairment in adolescents with variants of sexual differentiation (DSD) and to develop treatment strategies so that biological paternity can become possible.

To enable the empowerment of young people with a DSD diagnosis, we have developed a training program (based on the ModuS concept) for patients and their parents as part of the Empower-DSD consortium project funded by the innovation fund.

In order to improve communication with other centers or other doctors and thereby optimize the medical care of young people with a DSD diagnosis, we are working on the development of a medical care network throughout Germany as part of the “DSD Care” project. This consortium project (consortium leadership University of Lübeck) is funded by the Federal Ministry of Health (BMG).

  • Research focus

    • Chromosomal peculiarities (e.g. Klinefelter syndrome; 47, XXY, chromosomal mosaic forms, XX testicular DSD (= "XX-Male"))
    • Incorrect development of the testes (e.g. as a result of a Maldescensus testis or from a genetic cause (e.g. SF1 = NR5A1 mutations))
    • Disorders of androgen biosynthesis or effects (e.g. 17-ß-HSD3 deficiency with male phenotype, partial androgen insensitivity (PAIS) or 5-alpha-reductase deficiency)
    • Disorders of GnRH formation or effect (in congenital hypogonadotropic hypogonadism (CHH) or Kallmann syndrome)
    • Functional (potentially reversible) disorders of the central gonadotropic axis (e.g. due to eating disorders (anorexia nervosa or obesity per magna) or if the central axis functions are impaired by drugs)
    • Disorders of the gonadotropic axis with simultaneous adrenal insufficiency (adrenogenital syndrome (AGS) with 21-hydroxylase deficiency; DAX1 (NROB1) mutation)
    • Impairment of testicular function in the lysosomal storage disease "infantile nephropathic cystinosis"
  • Literature

    All publicationens of Julia Rohayem are given here (Pubmed)

    Selected literature:

    Rohayem J, Bäumer LM, Zitzmann M, Fricke-Otto S, Mohnike K, Gohlke B, Reschke F, Jourdan C, Müller HL, Dunstheimer D, Weigel J, Jorch N, Müller-Roßberg E, Lankes E, Gätjen I, Richter-Unruh A, Hauffa BP, Kliesch S, Krumbholz A, Bramswig J. Semen quality and testicular adrenal rest tumor development in 46,XY congenital adrenal hyperplasia - the importance of optimal hormonal replacement. Eur J Endocrinol. 2021 Feb 1:EJE-20-1154.R3. doi: 10.1530/EJE-20-1154. Epub ahead of print. PMID: 33524003.

    Rohayem J, Zitzmann M, Laurentino S, Kliesch S, Nieschlag E, Holterhus PM, Kulle A. The role of gonadotropins in testicular and adrenal androgen biosynthesis pathways-Insights from males with congenital hypogonadotropic hypogonadism on hCG/rFSH and on testosterone replacement. Clin Endocrinol (Oxf). 2021 Jan;94(1):90-101. doi: 10.1111/cen.14324. Epub 2020 Sep 24. PMID: 32871622.

    Zitzmann M, Rohayem J. Gonadal dysfunction and beyond: Clinical challenges in children, adolescents, and adults with 47,XXY Klinefelter syndrome. Am J Med Genet C Semin Med Genet. 2020 Jun;184(2):302-312. doi: 10.1002/ajmg.c.31786. Epub 2020 May 16. PMID: 32415901.

    Rohayem J, Luberto A, Nieschlag E, Zitzmann M, Kliesch S. Delayed treatment of undescended testes may promote hypogonadism and infertility. Endocrine. 2017 Mar;55(3):914-924. doi: 10.1007/s12020-016-1178-0.

    Rohayem J, Hauffa BP, Zacharin M, Kliesch S, Zitzmann M; “German Adolescent Hypogonadotropic Hypogonadism Study Group”. Testicular growth and spermatogenesis: new goals for pubertal hormone replacement in boys with hypogonadotropic hypogonadism? -a multicentre prospective study of hCG/rFSH treatment outcomes during adolescence. Clin Endocrinol (Oxf). 2017 Jan;86(1):75-87. doi: 10.1111/cen.13164.

    Rohayem J, Drechsel H, Tittel B, Hahn G, Pfaeffle R, Huebner A. Long-Term Outcomes, Genetics, and Pituitary Morphology in Patients with Isolated Growth Hormone Deficiency and Multiple Pituitary Hormone Deficiencies: A Single-Centre Experience of Four Decades of Growth Hormone Replacement. Horm Res Paediatr. 2016;86(2):106-116. doi: 10.1159/000448098. 27487097.