INVITED SPEAKERS / COMUNICAÇÕES POR CONVITE

 

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X-Imbalances big and small

 

 

Nicole de Leeuw^I

^IDepartment of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands. E-mail: nicole.deLeeuw@radboudumc.nl

 

 

The Xchromosomeisfascinating, buttheclinicalinterpretation of X-chromosomal aberrations are often a challenge, in particular because of (possible) mosaicism and X-inactivation.

Various abnormalities involving X will be addressed in this lecture, including whole chromosome numerical abnormalities, supernumerary marker chromosomes, X-autosome translocations as well as recurrent and non-recurrent copy number variations. For many indications, molecular techniques such as QF-PCR and genome wide array analysis are nowadays often used to test the patient samples in prenatal and postnatal genome diagnostics. For the correct interpretation of these data, however, cytogenetic knowledge is necessary and often routine cytogenetic analysis and /or Fluorescence In Situ Hybridisation (FISH) is required to further characterise the X-chromosomal abnormality.

After doing the tests, it is crucial for the clinical laboratory geneticist to not only correctly use the existing nomenclature in the test report, but also to include a clear and concise explanation of what the test result means. The requesting clinician needs to understand the meaning of the laboratory findings and the underlying genetic mechanisms in order to be able to properly counsel the patient and the parents with regard to prognosis and recurrence risk.

A variety of illustrative case examples will be presented to address the aforementioned aspects, but most likely, some questions will remain unanswered.