Test Update Memorandum – FMR1 – Related Disorders Repeat Expansion Analysis

Effective 5/17/2013, the Medical Genetics Laboratories at Baylor College of Medicine will change the
methodology for FMR1 – Related Disorders Repeat Expansion Analysis. The following test codes will

  • Test code 6032 (Repeat Expansion Analysis) will be replaced by test code 6573.
  • Test code 6091 (Repeat Expansion Analysis – Prenatal) will be replaced by test code

The price will remain the same.

An updated requisition will be posted on the MGL website on 5/17/2013 for download. Please use this
updated requisition to submit your future test requests. Any test requests received after 5/17/2013 will
be automatically accessioned to the new codes 6573 and 6574.

New Methodology

The methodology for this testing has been updated for use of optimized PCR analysis, which is able to
detect a larger range of allele sizes from normal size to disease-associated repeat lengths of greater than
200 repeats in a single assay. For samples in which an expansion greater than 200 repeats is detected,
methylation analysis utilizling PCR and/or Southern analysis will be performed on a reflex basis.

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