PPM – Chromosome and FISH Analyses of Patients with Suspicion of Turner Syndrome-Description and References

Description and References

Pdf Summary

This document provides an overview of recommendations for chromosome analysis, including possible fluorescence in situ hybridization (FISH) testing, for patients suspected of having Turner syndrome. The module does not address the primary assessment using chromosomal microarray. Laboratory Directors are asked to select five consecutive cases, including prenatal and postnatal specimens, that indicate possible Turner syndrome. The module includes 17 questions regarding the work-up of each case.<br /><br />The learning objectives of the module are to implement laboratory practice guidelines to improve diagnosis and direct follow-up for patients with Turner syndrome.<br /><br />Turner syndrome is a chromosomal disorder characterized by the complete absence or partial loss of critical X chromosomal regions. In 45% of cases, females with Turner syndrome have a 45,X karyotype with the complete loss of the second X chromosome. Structural aberrations of the second X chromosome have been reported in 20-30% of cases, and 5-10% of cases have mosaicism for the Y chromosome or structural abnormalities of the Y chromosome.<br /><br />With complex and/or mosaic karyotypes identified in over 50% of Turner syndrome cases, standards and guidelines for appropriate laboratory testing were published in 2010 and updated in 2012. The document also refers to additional literature on the topic.<br /><br />Overall, this document provides a summary of recommendations and guidelines for conducting chromosome and FISH analyses to diagnose and follow up on patients suspected of having Turner syndrome.

Keywords

chromosome analysis

fluorescence in situ hybridization

FISH testing

Turner syndrome

chromosomal microarray

laboratory practice guidelines

diagnosis

follow-up

X chromosome

Y chromosome