NEUROFIBROMATOSIS Type 1

Prenatal Detection of Known Mutation (PT2)                            

DESCRIPTION

Mendelian Inheritance in Man number: 162200

Click here for Gene Reviews Clinical Summary.

Neurofibromatosis type 1 is a completely penetrant, autosomal dominant disorder with a frequency of 1/3500 births in all ethnic populations. NF1 is a progressive disorder, characterized by multiple café-au-lait spots, neurofibromas, and Lisch nodules, although additional features may develop.  NF1 is notorious for its variable expression. About 50% of cases are due to new dominant mutations, where neither parent has signs of the disorder. An affected individual has a 50% risk of transmitting NF1 to each offspring, although the degree of severity can differ from person to person, even within the same family. 
 

INDICATIONS FOR DIRECT TESTING

  • Prenatal predictive testing for individuals at risk of inheriting an already known NF1 mutation


TESTING METHODOLOGY

We offer a targeted detection of a previously characterized NF1 mutation within the family.  For prenatal diagnosis, fresh or cultured CVS or amniocytes can be used for diagnostic purposes. DNA is extracted directly and the target region is amplified and analyzed for the presence or absence of the specific mutation. Maternal cell contamination is analyzed by amplification of microsatellite markers in the DNA of the maternal and fetal sample.  All prenatal samples are performed in duplicate and independently by two technicians. 

SPECIMEN REQUIREMENTS

(1) minimum of 15 mg of chorionic villus specimen. Send specimen in transport media in 15-mL centrifuge tube.

(2) 20 mL of amniotic fluid. Send specimen refrigerated, but not frozen.

(3) 2-T25 flasks of cultured CVS (>70% confluent), sent at ambient temperature.

(4) 2-T25 flasks of cultured amniocytes. (>70% confluent), sent at ambient temperature.

Please also send 1-5 ml of blood or buccal swab sample from the mother for maternal contamination studies.
 

TRANSPORT

If specimen is from clinics within UAB or Kirklin Clinic, please call 934-7107 for pick-up. If specimens are being sent from some other location, please ship via UPS or Federal Express.

1. Be sure that the shipping air bill is marked “Priority”, either Domestic or International.
2. Specimens must be packaged to prevent breakage and absorbent material must be included in the package to absorb liquids in the event that breakage occurs.  Also, the package must be shipped in double watertight containers (e.g. a specimen pouch + the shipping companies Diagnostic Envelope). You can use our collection kits, which we will send to physicians directly upon request.
3.   Please contact us (Email – medgenomics@uabmc.edu, Phone – 205-934-5562) prior to sending a sample for prenatal testing and provide us with the date of shipment and the tracking number of the package, so that we can better ensure receipt of the samples.


TURN AROUND TIME

6 working days after sample is received


CPT CODES AND PRICES

Please find the most up to date prices and CPT codes for our testing services under the "Prices" tab of this website.



REQUIRED FORMS

NF1 Test Requisition

*Please note that phenotypic checklist is not required for prenatal testing.

Form for customs (International shipment)

Note: Detailed and accurate completion of this document is necessary for reporting purposes. The Medical Genomics Laboratory issues its clinical reports based on the demographic data provided by the referring institution on the lab requisition form. It is the responsibility of the referring institution to provide accurate information. If an amended report is necessary due to inaccurate or illegible documentation, additional reports will be drafted with charge.

Requests for Molecular Genetic testing for NF1-KT2 will not be accepted for the following reasons:

  • No label (patients full name and date of collection) on the specimens
  • No referring physician’s or genetic counselor’s names and addresses
  • No billing information
  • No informed consent

 

For more information, test requisition forms, or sample collection and mailing kits, please call: 205-934-5562.
 

REFERENCES

Gutmann DH, Aylsworth A, Carey JC, Korf B, Marks J, Pyeritz RE, Rubenstein A, Viskochil D. (1997) The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA. Jul 2; 278(1): 51-7. Review. (pubmed)

Huson, SM; Hughes, RAC: The Neurofibromatoses: a Pathogenetic and Clinical Overview. London: Chapman & Hall Medical, 1994. (pubmed)

Maertens O, De Schepper S, Vandesompele J, Brems H, Heyns I, Janssens S,

Speleman F, Legius E, Messiaen L (2007) Molecular dissection of isolated disease features in mosaic neurofibromatosis type 1. Am J Hum Genet 81(2):243-251. (pubmed)

Messiaen LM, Callens T, Mortier G, Beysen D, Vandenbroucke I, Van Roy N, Speleman F, De Paepe A (2000) Exhaustive mutation analysis of the NF1 gene allows identification of 95% of mutations and reveals a high frequency of unusual splicing defects. Hum Mutat.15(6):541-55. (pubmed)

Messiaen L and Wimmer K (2005) Pitfalls of automated comparative sequence analysis as a single platform for routine clinical testing for NF1. J. Med. Genet. 42(5): e25. (pubmed)

Messiaen LM and Wimmer K (2008) NF1 Mutational Spectrum in Kaufmann D (ed): Neurofibromatoses. Monogr Hum Genet. Basel, Karger, Vol 16:63-77 (pubmed)

Wimmer K,  Roca X, Beiglbock H, Callens T, Etzler J, Rao A, Krainer A, Fonatsch C, Messiaen L (2007) Extensive in silico analysis of NF1 splicing defects uncovers determinants for splicing outcome upon 5’ splice-site disruption. Hum Mutat. 28(6): 599-612. (pubmed)