# Changes

$V_{meta,i}=\sum_{k=1}^S{V_{ii,k}}$
Then the score test statistics for the $i^{th}$ variant $T_{meta,i}$ asymptotically follows standard normal distribution
$T_{meta,i}=U_{meta,i}\bigg/\sqrt{V_{meta,i}}=\sum_{k=1}^S {U_{i,k}}\bigg/\sqrt{\sum_{k=1}^S{V_{ii,k}}} \sim\mathbf{N}(0,1)$