Fragile X Syndrome, Molecular Analysis (FXS)

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Test Code: FXMOLSO

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Ref Lab Code: 9569, FMR1, Fragile X tremor ataxia syndrome, FXTAS,Martin-Bell Syndrome, POF, Premature ovarian failure

Useful For

Determination of carrier status for individuals with a family history of fragile X syndrome or X-linked mental retardation

Confirmation of a diagnosis of fragile X syndrome, fragile X tremor/ataxia syndrome, or premature ovarian failure caused by expansions in the FMR1 gene

Prenatal diagnosis of fragile X syndrome when there is a documented FMR1 expansion in the family

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)
Submit only 1 of the following specimens:
Whole blood	EDTA Lavender Top tube (LTT) or Yellow Top Tube (ACD)	Any anticoagulant	3 mL	0.5 mL
Amniotic fluid	Amniotic fluid container		20 mL	10 mL
Chorionic villi	15-mL tube containing 15 mL of transport media		20 mg	5 mg
Confluent cultured cells	T-25 flask		2 flasks

Collection Processing Instructions

Forms:

1. Please document on the request form or electronic order that a copy is on file.

Molecular Genetics-Congenital Inherited Diseases Patient Information Sheet

Informed Consent for Genetic Testing

Specimen must arrive within 96 hours of collection.

Whole blood:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Amniotic fluid:

Due to the complexity of prenatal testing, consultation with the laboratory is required for all prenatal testing. Prenatal specimens can be sent Monday through Thursday and must be received by 5 p.m. CST on Friday in order to be processed appropriately. All prenatal specimens must be accompanied by a maternal blood specimen. Order MCC/88636 Maternal Cell Contamination, Molecular Analysis on the maternal specimen.

Chorionic villi:

Additional Information: FMR1-methylation status cannot be assessed on some chorionic villus specimens. Contact a genetic counselor/consultant at Mayo Medical Laboratories at 800-533-1710 or 507-266-5700 to discuss the limitations of testing prior to sending a chorionic villus specimen for fragile X analysis.

Confluent cultured cells:

Submit confluent cultured cells from another laboratory.

Specimen Stability Information

Specimen Type	Temperature
Whole blood	Ambient (preferred)
	Refrigerated
Amniotic fluid	Ambient (preferred)
	Refrigerated
Chorionic villi	Refrigerated
Confluent cultured cells	Ambient (preferred)
	Refrigerated

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Analytical Time	Methodology/Instrumentation
Mayo Medical Laboratories	Monday, Wednesday	4-10 days	Polymerase Chain Reaction (PCR)-Based Assays (PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)

Reference Lab

Mayo Clinic Laboratories

Reference Range Information

Interpretive report

Interpretation

An interpretive report will be provided.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
81243
88233			Fibroblast Culture - Tissue Culture Skin/Biopsy (as needed)
88240			Fibroblast Culture - Cell Cryopreserve/Storage (as needed)
88235			Amniotic Fluid Culture/Genetic Test - Amniotic Fluid or Chorionic (as needed)
88240			Amniotic Fluid Culture/Genetic Test - Cryopreservation (as needed)
81265			Maternal Cell Contamination (as needed)
81244			Fragile X, Follow-up Analysis (as needed)