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.
- 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.
Counseling and informed consent are recommended for genetic testing. A consent form
is available as a resource but not required.
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.