Molecular Human Reproduction, Vol. 7, No. 7, 692-693,
July 2001
© 2001 European Society of Human Reproduction and Embryology
Letter to the editor |
The role of USP9Y and DBY in infertile patients with severely impaired spermatogenesis
Laboratoire de Géétique, Biologie du Développment et de la Reproduction, EA 3185, Genetique et Reproduction, Faculte de Medicine et de Pharmacie, Place Saint-Jacques, 25030, Besançon Cedex, France
Dear Sir,
The letter of Van Landuyt et al. entitled `The role of USP9Y and DBY in infertile patients with severely impaired spermatogenesis' encouraged us to take part in the discussion concerning the following points.
The use of paraffin embedded tissues
Many procedures have been developed to extract nucleic acids from this material in a form that can be then used for PCR. Many authors suggest that this material can be used for an amplification of short fragments (Longy et al., 1997; Fredricks and Relman, 1999
).
The frequency of Yq11 deletions
This may vary in different research centres and in different groups of patients. Moreover, different approaches for patient selection could explain these disagreements. A high frequency (55%) of AZF deletions has been demonstrated in a group of patients with Sertoli-cell-only syndrome (SCOS) (Foresta et al., 1998).
Selection of patients
The use of histological and/or immunohistological criteria may influence the frequency of microdeletion detection, especially because the usual definition of SCOS (absence of germ cells) is too large. We examined 500 testicular biopsies and only 22 cases were included in our study.
The significance of markers
DFFRY (USP9Y) was used essentially as a marker of the AZFa region, and only secondarily for the detection of USP9Y microdeletions. We observed a high frequency (18%) of AZF deletions without the possibility of evaluating an extension of the deletion and the implication for other AZFa genes (DBY). The combined deficiency of DFFRY and DBY seems required to induce the SCOS phenotype, whereas an absence of DBY may be associated with azoospermia and/or severe oligozoospermia (Foresta et al., 2000).
Possible relationships between AZF deletion frequency and tissue origin of DNA
The studies on the blood DNA may underestimate the frequency of the deletions.
Possible role of ethnic factors
The rates of AZFa deletion may vary substantially between different ethnic groups (Blanco et al., 2000). Because the relationship between the deletion site and spermiogram parameters are not established, we think it useful to perform detailed investigation of gonad histology in patients with AZF microdeletions.
References
Blanco, P., Shlumukova, M., Sargent, C.A. et al. (2000) Divergent outcomes of intrachromosomal recombination on the human Y chromosome: male infertility and recurrent polymorphism. J. Med. Genet., 37, 752–758.
Foresta, C., Ferlin, A. and Moro, E. (2000) Deletion and expression analysis of AZFa genes on the human Y chromosome revealed a major role for D BY in male infertility. Hum. Mol. Genet., 9, 1161–1169.
Foresta, C., Ferlin, A., Garolla, A. et al. (1998) High frequency of well-defined Y-chromosome deletions in idiopathic Sertoli cell-only syndrome. Hum. Reprod., 13, 302–307.
Fredricks, D.N. and Relman, D.A. (1999) Paraffin removal from tissue sections for digestion and PCR analysis. Biotechniques, 26, 198–200.[ISI][Medline]
Zongy, M., Duboue, B., Soubeyran, P. et al. (1997) Method for the purification of tissue DNA suitable for PCR after fixation with Bouin's fluid. Uses and limitations in microsatellite typing. Diagn. Mol. Pathol., 6, 167–173.[ISI][Medline]
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