Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited blood disorder characterized by the body’s insufficient production of the G6PD enzyme. This enzyme plays a role in red blood cell function, particularly in protecting these cells from damage. A deficiency can lead to red blood cells breaking down prematurely, impacting their ability to carry oxygen throughout the body.
Understanding G6PD Deficiency
The G6PD enzyme protects red blood cells from oxidative stress. This stress occurs when harmful byproducts accumulate in the cells. Without enough G6PD, red blood cells become vulnerable and can break down, a process known as hemolysis, leading to hemolytic anemia.
This condition is an X-linked recessive genetic disorder, meaning it is more common in males, while females are typically carriers. G6PD deficiency affects approximately 400 to 500 million people globally, with a higher prevalence in populations from Africa, the Mediterranean, and Asia. This widespread presence is thought to be an evolutionary adaptation, as the deficiency offers some protection against malaria in regions where the disease is common.
How It Affects Newborns
Neonatal jaundice, or hyperbilirubinemia, is the most common and significant manifestation of G6PD deficiency in newborns. The rapid breakdown of red blood cells due to the deficiency produces high levels of bilirubin, a yellow pigment. This excess bilirubin accumulates in the body, causing the skin and whites of the eyes to appear yellow.
Severe, unmanaged jaundice in newborns can pose a serious risk. High levels of bilirubin can cross the blood-brain barrier and lead to kernicterus, a rare but severe form of brain damage. Other less common signs of hemolytic anemia in newborns may include pallor or dark-colored urine.
Diagnosis and Newborn Screening
G6PD deficiency is typically identified through universal newborn screening programs. These screenings often include a G6PD test, usually performed via a heel prick blood sample taken shortly after birth. Early diagnosis helps prevent severe complications, particularly the development of severe jaundice and its potential neurological consequences.
If the initial newborn screen shows an abnormal or inconclusive result, follow-up testing is often recommended. Quantitative assays, which measure the precise level of G6PD enzyme activity, are considered the standard for confirming a diagnosis.
Managing the Condition and Triggers
Managing G6PD deficiency primarily involves avoiding triggers that can cause red blood cell breakdown. Common triggers include certain medications, such as some antimalarial drugs, sulfa drugs, and aspirin. Exposure to certain chemicals like naphthalene, found in mothballs, should also be avoided.
Specific foods, most notably fava beans, can also trigger hemolytic episodes, a condition sometimes referred to as favism. Infections can also induce oxidative stress and lead to red blood cell destruction. It is important to inform all healthcare providers about the diagnosis to ensure appropriate medication and care.
In cases of acute hemolytic episodes, particularly severe jaundice, medical interventions may be necessary. These can include phototherapy, which uses light to break down bilirubin in the skin, or, in more severe instances, exchange transfusions to replace affected blood cells. Parents should seek prompt medical attention for any signs of jaundice or illness in a child with G6PD deficiency.