Dopamine Beta-Hydroxylase (DβH) Deficiency
What is DβH deficiency?
Dopamine beta-hydroxylase deficiency is a condition affecting the autonomic nervous system. Autonomic means “happening involuntarily.” The autonomic nervous system is responsible for regulating blood pressure and body temperature, among other involuntary functions of the body.
Dopamine beta-hydroxylase is an enzyme that converts dopamine into norepinephrine. Both dopamine and norepinephrine are neurotransmitters, meaning they are responsible for communication between different nerve cells in the brain.
What are the symptoms of DβH deficiency?
Symptoms of dopamine beta-hydroxylase deficiency may begin at birth. Most symptoms will start in early childhood and get progressively worse with age.
DβH deficiency can be accompanied by episodes of vomiting, dehydration, and nasal congestion. Eyelids may droop, a condition known as ptosis. The most serious symptoms are an inability to regulate body temperature and low blood pressure (hypotension). In particular, those with DβH deficiency may experience a severe drop in blood pressure when standing (orthostatic hypotension). Drops in blood pressure may contribute to other symptoms, including dizziness, blurred vision, and fainting. Orthostatic hypotension may be more severe in the mornings (such as when getting out of bed), with increased environmental temperature, and with age.
Due to the inability to regulate blood pressure and body temperature, those with DβH deficiency have trouble exercising and may experience extreme fatigue.
Men with DβH deficiency may also experience retrograde ejaculation—a discharge of semen backwards into the bladder.
Less common side effects include an unusual range of join mobility (hypermobility) and muscle weakness.
How is DβH deficiency diagnosed?
Diagnosing dopamine beta-hydroxylase deficiency is based on a blood test that would reveal high levels of dopamine and extremely low levels of norepinephrine. These levels are because of the body’s inability to convert dopamine to norepinephrine.
Where does DβH deficiency come from?
Dopamine beta-hydroxylase deficiency is a result of mutations to the DβH gene. This gene provides the instructions for the body to produce DβH. DβH deficiency may also be inherited in an autosomal recessive pattern. Conditions which are inherited in this way require each parent of an affected individual to carry one copy of the mutated gene. Typically these carriers do not show signs of the condition.
Is there treatment for DβH deficiency?
There is treatment in the form of synthetic norepinephrine, which can help reduce low blood pressure, dizziness, fainting spells, and other symptoms associated with the orthostatic hypertension part of the condition.
Where can I find more information on DβH deficiency?