The purpose of this research is to determine if saliva samples can be used as an alternate sample type to test for fragile X. By using saliva instead of blood, it would be easier for patients to have fragile X testing.

Saliva samples will be prospectively collected from subjects who have previously been tested by Esoterix Genetic Laboratories, LLC using blood specimens and diagnosed as fragile X intermediates, premutations (carriers) or full mutations (affected). Results from fragile X testing with saliva will be compared to results from the blood sample that was previously submitted to Esoterix Genetic Laboratories for testing.

Data from this study will be used for regulatory submissions.

Inclusion Criteria:

• Subject has previously been identified through molecular testing at Esoterix Genetic Laboratories as a Fragile X intermediate, premutation (carrier) or full mutation (affected).
• In the opinion of the subject's physician, the subject is medically stable and able to provide the required quantity of saliva.
• If Subject is at least 18 years of age:
• Subject must be willing to give written informed consent
• Subject must be willing to comply with the collection procedure
• If Subject is under 18 years of age, the legally authorized representative must give written informed consent and agree to comply with study procedures.

Exclusion Criteria:

• Subject has been determined to be an individual with a normal FMR1 gene.
• Subject has a known medical condition that would cause risk to the donor or, if relevant, the fetus as a result of saliva collection.

Fragile X full mutations (affecteds), fragile X premutations (carriers), and fragile X intermediates who previously had fragile X testing through Esoterix Genetic Laboratories. Subject population will be in the US.