The "HBs disease" most commonly refers to Sickle cell disease, where "HBs" denotes hemoglobin S, the abnormal type of hemoglobin that causes the disease.
Sickle cell disease is a group of inherited red blood cell disorders. People with sickle cell disease have red blood cells that contain abnormal hemoglobin, called sickle hemoglobin or HbS. HbS causes red blood cells to become hard and sticky and look like a C-shaped farm tool called a "sickle." The sickle cells die early, causing a constant shortage of red blood cells. Also, when they travel through small blood vessels, they get stuck and block the blood flow. This can cause pain and other serious problems like infection, acute chest syndrome, and stroke.
The inheritance pattern is autosomal recessive, meaning a person must inherit two copies of the mutated gene (HbS) – one from each parent – to develop the disease. Alternatively, inheriting one copy of HbS and another beta-globin variant (like HbC) can also result in disease expression.
