GSTM1 and Schnyder corneal dystrophy: In 2006, the WHO recognized hemoglobinopathies, including sickle cell disease (SCD), as a global public health problem and Oman has a high prevalence of hemoglobin (Hb) disorders (3) (http://apps.who.int/iris/bitstream/handle/10665/20890/A59_9-en.pdf?sequence=1&isAllowed=y).