A stepwise haematological screening and whole-exome sequencing reveal multiple mutations from SUPT5H causing an elevation of Hb A 2 from a cohort of 47336 individuals.

. According to the previous observations that individuals with a combination of β-thal mutation and a SUPT5H variant might present moderate β-thaelassemia, these findings emphasized the importance of comprehensive molecular diagnosis to prevent birth defects of β-thaelassemia caused by rare mutations from modifier genes.