sickle cell disease
(scd) is term that encompasses a group of inherited red blood cell disorders. people with this chronic, multi-system disease have red blood cells that contain an abnormal form of hemoglobin, known as hemoglobin s (for sickle), that causes cells to become hard, sticky and sickle-shaped in appearance.
while normal red blood cells contain hemoglobin a and survive for around 120 days before being replaced, red blood cells that produce hemoglobin s only live for about 16 days and their abnormal form causes them to get stuck while travelling through blood vessels.
according to the sickle cell society of america
, this can impede the flow of oxygen-rich blood to vital areas of the body and cause tissue damage that gives rise to the complications of the disease.
the type of hemoglobin a person produces in their red blood cells depends on the hemoglobin gene they inherit from their parents. the most common form of scd occurs when a person inherits a hemoglobin s producing gene from both parents. this is known as hbss, or sickle cell anemia, and is generally the most severe from of the disease.
children who inherit only one scd gene can produce hemoglobin a and hemoglobin s and generally do not experience symptoms of the disease, but they can still pass it on to their children. despite advances treatment, studies have estimated that scd patients have a lifespan that is 20 years shorter than people without the disease.
symptoms of sickle cell disease
while scd varies from patient to patient, symptoms usually begin to appear at six months of age.
according to the hospital for sick children
, the two symptoms most characteristic of the disease are: