ACSS2 and hemoglobin H disease: In addition, we detected 20 cases with HbH disease, ten fetuses with deletion HbH disease (8 with --SEA/-α3.7 and 2 with --SEA/-α4.2), 4 fetuses with --SEA/α WSα, 4 fetuses with --SEA/αCSα and 2 fetuses with --SEA/αQSα.