MAPT H1 haplotype — small Parkinson's and tauopathy risk shift
Two copies of the MAPT H1 haplotype.
You have two copies of the H1 version of the MAPT gene region.
Associated with a small lifetime increase in risk for Parkinson's disease and certain rare tauopathies, but the effect is modest relative to lifestyle and age.
Your lifetime chance of Parkinson's disease and some rare brain conditions involving the tau protein is slightly higher than average. The effect is small compared with lifestyle and age.
What this means
MAPT encodes the tau protein, which forms the tangles seen in Alzheimer's and several rarer "tauopathies" (progressive supranuclear palsy, corticobasal degeneration). The gene region has two ancient haplotypes (H1 and H2). H1 is associated with a small increase in risk of these conditions, but the effect is modest and most carriers never develop them.
MAPT makes the tau protein, which forms the tangles seen in Alzheimer's and in several rarer brain conditions (progressive supranuclear palsy and corticobasal degeneration). This region of DNA comes in two ancient versions: H1 and H2. The H1 version is linked to a small increase in the chance of these conditions, but the effect is modest and most people with H1 never develop any of them.
Caveats
- The effect size is small — odds ratios near 1.2 for Parkinson's.
- This is a haplotype tag, not a single causal variant. Different studies use different tagging SNPs.
- H2 is much less common outside European populations, which affects how comparisons are framed.