Coenzyme Q10 deficiency

Overview

Coenzyme Q10 (Ubiquinone or CoQ10) is a lipid-soluble component of virtually all cell membranes and has multiple metabolic functions. Deficiency of Coenzyme Q10 has been associated with many different clinical presentations, including diverse muscle and brain related dysfunctions as well as lactic acidosis. Coenzyme Q10 deficiency can be tested via a muscle biopsy, where the actual concentration of the enzyme in the muscle tissue is determined. Coenzyme Q10 deficiency can be treated with oral Coenzyme Q10 supplementation.

 

Source:

Neurochem Res (2007) 32:723-72; Neuromuscul Disord 2012 Jan;22(1):76-86

 

 

 

Symptoms

Clinical recognition of Coenzyme Q10 deficiency is difficult because of its extreme clinical heterogeneity. None the less, some recognizable symptoms can be found:

- Recurrent rhabdomyolysis (break down of skeletal muscle tissue), associated with seizures and mental retardation

- Myopathy (muscle disease) or proximal muscle weakness

- Migraine

- Lactic acidosis (low pH in body tissues / blood and buildup of lactate)

- Encephalomyopathy (brain disfunction)

- Nephropathy (damage or disease of a kindey)

- Ataxia (lack of coordinated muscle movements)

- Leigh syndrome (neurometabolic disorder)

 

Source:

Neurochem Res (2007) 32:723-72; Neuromuscul Disord 2012 Jan;22(1):76-86

 

Causes

Coenzyme Q10 (CoQ10), also called ubiquinone, is necessary for the molecular process of respiration. In this process, ingested food is broken down into its molecular parts and used for the generation of energy for every cell in the body. During this process, oxygen is converted into water, hence the name “respiration”.

Coenzyme Q10 is a part of the electron transport chain in the inner membrane of mitochondria. In the mitochondria, the molecules NADH or FADH are oxidized to reduce oxygen and to build up an electrochemical proton gradient. The electrons are then transported through the membrane via integrated proteins (complex I to complex IV). During this process protons are transported from the matrix to the intermembrane space. The electrons finally reduce oxygen to water, whereas the protons are used to generate ATP, an ubiquitous molecule used to fuel a diverse set of biochemical reactions.

Without Coenzyme Q10, the cells of the body are insufficiently supplied with energy, which can have drastic consequences. Furthermore, Coenzyme Q10 is also involved in other cellular processes, since it is serving as an antioxidant, it is involved in DNA replication and repair and modulates cell death (apoptosis).

Deficiency in Coenzyme Q10 can occur through reduced biosynthesis, not enough dietary intake or increased utilization of the body. Mutations in six genes needed to synthesize Coenzyme Q10 can lead to a reduced formation rate up to a totally nonfunctional enzyme (PDSS1, PDSS2, COQ2, COQ6, COQ9, ADCK3). Coenzyme Q10 levels can also decrease with age or in some chronic diseases, such as heart conditions, Parkinson´s disease, diabetes, cancer or HIV/AIDS.

 

Source:

Genetics Home Reference; Mayo Clinic; Neuromuscul Disord 2012 Jan;22(1):76-86; Neurochem Res (2007) 32:723-727

 

Prevention

Not supplied.

Diagnosis

Initial biochemical testing can include the measurement of blood lactate, which allows assumptions about the Coenzyme Q10 concentration. On the other hand, a normal lactate level does not exclude a Coenzyme Q10 deficiency

As gold standard, the direct measurement of Coenzyme Q10 in a muscle biopsy is recommended.

 

Source:

Neuromuscul Disord 2012 Jan;22(1):76-86

 

Prognosis

Oral treatment with Coenzyme Q10 leads to an improvement of muscle abnormalities, whereas cerebral symptoms are only partially ameliorated.

 

Source:

Neurochem Res (2007) 32:723-727

 

Treatment

Patients with Coenzyme Q10 deficiency have shown clinical improvement with oral Coenzyme Q10 supplementation. Adults can be treated with 1200 - 3000 milligrams of Coenzyme Q10 daily, children should be treated with a daily dose of 10-30 mg/ kg and day. The response of this treatment is dependend on the underlying cause of the disease. Patients with a mutation in COQ2 respond well on oral supplementation, whereas the response in patients with mutation in the genes PDSS2 or COQ9 is poorer.

 

Source:

Neuromuscul Disord 2012 Jan;22(1):76-86; Neurochem Res (2007) 32:723-727

 

Resources

Not supplied.