Frontotemporal Dementia w/ Parkinsonism (FTDP) - Mapt Gene

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FRONTOTEMPORAL DEMENTIA W/ PARKINSONISM (FTDP) - MAPT GENE

Gene Symbol: MAPT

Chromosomal Locus: 17q21
 
Protein: Microtubule-Associated Protein Tau
 
Pseudonyms: Frontotemporal Dementia with Parkinsonism, Pick disease, FTDP-17, tauopathy
 
TURNAROUND TIME: 4 weeks
   
TESTING METHODOLOGY: Polymerase chain reaction (PCR) followed by sequencing of all the coding exons (1-5,7,9, and 10-14) and intron / exon borders of the MAPT gene.
 
SPECIMEN REQUIREMENTS:
  • Collect: Prefer two 5ml whole blood EDTA (lavender top) tube.
  • Min. Collection: 0.7 ml whole blood EDTA.
  • Transport: blood EDTA at Room Temp shipped regular next day air (No Sat. delivery; store specimen at 4°C and ship Mon.).
  • Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
  • Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.
  • Prenatal testing: Direct: 5ml direct unspun amniotic fluid or 15mg CVS tissue with a backup flask growing. Culture: confluent T25 flask. Maternal blood sample is required for maternal cell contamination studies.
A Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
 
Incidence: Unknown.
 
Inheritance: Autosomal dominant.
 
Disease Characteristics: FTDP-17 features include behavioral and personality changes, cognitive decline, dementia and motor abnormalities. MAPT -related FTD is distinct by the fact that there are tau deposits rather than the ubiquitin-associated inclusions found with PGRN - related FTD.
 
Molecular Genetic Mechanism: A variety of mutations have been described throughout the gene. However, the exon 10 region is considered a hotspot.
 
 
Clinical Sensitivity: 20-30% of individuals with a family history of FTDP will have a mutation in the MAPT gene; the sequencing assay will detect 90% of those mutations.
 
Analytical Sensitivity: 99%
 
Test Limitations: Mutations that are not located within the tested regions. Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
 
INDICATIONS FOR USE:
  • To confirm the nature of the dementia in an affected individual and determine inheritance risks.
  • Presymptomatic testing for a known familial mutation.
ADDITIONAL RESOURCES:
OMIM - Frontotemporal Dementia: http://omim.org/entry/600274