BACH2–NRF2: A New Genetic Route to Fetal Hemoglobin

Fetal hemoglobin (HbF) is a form of hemoglobin that is normally replaced by adult hemoglobin after birth. Researchers at Boston Children’s Hospital, Dana-Farber Cancer Institute, and the Broad Institute have implicated a separate BACH2–NRF2 pathway in regulating HbF, raising a possible new direction for research on sickle cell disease and beta thalassemia. The findings identify a candidate target; they do not show that a treatment based on it is safe or effective in patients.49

How researchers found the pathway

The researchers began with human genetics: they looked across a multi-ancestry group of 28,279 people for genetic differences associated with HbF levels. The analysis identified HbF-linked regions and nominated BACH2 as a regulator. A report of the study describes 91 conditionally independent associations across 12 genomic regions.

One high-HbF-associated variant was linked to lower BACH2 expression. That relationship suggested a testable idea: if BACH2 normally restrains HbF production, reducing its activity might allow HbF to rise. Follow-up perturbation experiments supported BACH2’s functional role, moving the evidence beyond association alone.

What the BACH2–NRF2 mechanism may do

The proposed model is that BACH2 acts as a brake on genes that encode the gamma-globin chains of HbF. When BACH2 is reduced, NRF2 has greater chromatin occupancy and can support activation of those HbF-producing genes.

This offers a plausible explanation for how inherited variation affecting BACH2 could influence HbF. The available source descriptions support the genetic association and the proposed mechanism, but do not provide enough detail to specify a particular blood stem-cell assay or to claim that the pathway has been validated as a therapeutic intervention in people.

Why it matters for blood disorders

HbF is described as a healthy, non-sickling form of hemoglobin. Increasing it is an established therapeutic goal in sickle cell disease and beta thalassemia, where adult hemoglobin is affected by disease-causing mutations.34 Existing gene therapies use the BCL11A pathway to reactivate HbF; the BACH2–NRF2 pathway appears to regulate HbF independently of BCL11A.49

That distinction makes BACH2–NRF2 interesting as a potential additional research target. It might eventually suggest a different way to increase HbF, or a route to investigate alongside BCL11A-based approaches. But the sources do not establish that combining the pathways would improve outcomes, or that targeting BACH2 would be safe for blood stem cells.89

What still needs to be established

Before BACH2–NRF2 could be considered a treatment strategy, further research would need to determine whether its effects can be produced reliably and durably, how changing the pathway affects blood stem-cell function, and whether the approach is safe. The current findings support biological promise—not a clinical recommendation or proof of patient benefit.8