Hemoglobin disorders are a group of conditions causing chronic anemia due to low production of red blood cells or faulty production of red blood cells. Also known as hemoglobinopathies, these disorders are genetic diseases of the hemoglobin.
References:
https://www.cdc.gov/ncbddd/thalassemia/index.html
https://medlineplus.gov/ency/article/000587.htm
https://www.mayoclinic.org/diseases-conditions/thalassemia/symptoms-causes/syc-20354995
https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease
https://medlineplus.gov/genetics/condition/sickle-cell-disease/