Show Summary Details
Page of

Cytogenetics and molecular genetics 

Cytogenetics and molecular genetics
Chapter:
Cytogenetics and molecular genetics
Author(s):

Dieter Meschede

and Frank Tüttelmann

DOI:
10.1093/med/9780199235292.003.9050
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 17 November 2019

Genetic aberrations are important causes of spermatogenic and endocrine testicular failure. Often, clinical skills are insufficient to demonstrate the primary genetic nature of a gonadal disorder, and cytogenetic and molecular tests should be considered for the diagnostic process (Table 9.5.3.1) (1–7). They are helpful, not only for establishing the basic aetiology of certain types of male endocrine disturbances, but also in that karyotyping and some DNA tests have attained a pivotal role in genetic risk counselling for severely infertile couples. Also, the diagnosis of a chromosomal abnormality or single gene mutation in an infertile man can have repercussions for other members of his family. They may carry the same type of genetic aberration, and thus be at increased risk for inadvertent reproductive outcomes.

The most time-honoured method in male endocrinology is the analysis of banded metaphase chromosome preparations from blood lymphocytes, which remains of undiminished practical importance (8, 9). This technique allows for the direct visualization of the complete set of chromosomes in a somatic cell lineage and provides information on both chromosome number and structure. However, a regular karyotype in somatic cells, such as lymphocytes, does not necessarily translate into normal meiotic pairing and segregation of the chromosomes in the germ cell lineage. Meiotic cell preparations and ejaculated spermatozoa may thus be included in the diagnostic work-up of an infertile man. The place of these techniques is more in the realm of research than of daily clinical practice, as discussed below. In contrast, several molecular genetic tests are firmly established as valuable diagnostic tools. Details concerning the two most important tests, mutation analysis of the CFTR gene and screening for Y-chromosomal microdeletions, are given below.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.