Nucleoside bypass therapy is an experimental treatment aimed to restore the normal levels of deoxyribonucleotides (dNTPs) in mitochondria.

There are no treatments for MDDS, but some of the symptoms can be managed. For survivors living with MDDS, there are drugs to control epilepsy, and physical therapy can help with muscle control. Liver transplants may benefit people with liver involvement.

Currently, no cure for Zellweger syndrome is known, nor is a course of treatment made standard. Infections should be guarded against to prevent such complications as pneumonia and respiratory distress. Other treatment is symptomatic and supportive. Patients usually do not survive beyond one year of age.

Like many mitochondrial diseases, there is no cure for MERRF, no matter the means for diagnosis of the disease. The treatment is primarily symptomatic. High doses of Coenzyme Q10, B complex vitamins and L-Carnitine are the drugs that patients are treated with in order to account for the altered metabolic processed resulting in the disease. There is very little success with these treatments as therapies in hopes of improving mitochondrial function. The treatment only alleviates symptoms and these do not prevent the disease from progressing. Patients with concomitant disease, such as diabetes, deafness or cardiac disease, are treated in combination to manage symptoms.

Succinic acid has been used successfully to treat MELAS syndrome, and also Leighs disease. Patients are managed according to what areas of the body are affected at a particular time. Enzymes, amino acids, antioxidants and vitamins have been used.

Also the following supplements may help:

- CoQ10 has been helpful for some MELAS patients. Nicotinamide has been used because complex l accepts electrons from NADH and ultimately transfers electrons to CoQ10.

- Riboflavin has been reported to improve the function of a patient with complex l deficiency and the 3250T-C mutation.

- The administration of L-arginine during the acute and interictal periods may represent a potential new therapy for this syndrome to reduce brain damage due to impairment of vasodilation in intracerebral arteries due to nitric oxide depletion.

- There is also a case report where succinate was successfully used to treat uncontrolled convulsions in MELAS patients, although this treatment modality is yet to be thoroughly investigated or widely recommended.

Currently, there is no cure for infantile Refsum disease syndrome, nor is there a standard course of treatment. Infections should be guarded against to prevent such complications as pneumonia and respiratory distress. Other treatment is symptomatic and supportive. Patients show variable lifespans with some individuals surviving until adulthood and into old age.

Succinic acid has been studied, and shown effective for both Leighs disease, and MELAS syndrome. If the mutation is in succinate dehydrogenase then there is a build up of succinate, in which case succinic acid won't work so the treatment is with fumaric acid to replace the fumarate than can not be made from succinate. A high-fat, low-carbohydrate diet may be followed if a gene on the X chromosome is implicated in an individual's Leigh syndrome. Thiamine (vitamin B) may be given if a deficiency of pyruvate dehydrogenase is known or suspected. The symptoms of lactic acidosis are treated by supplementing the diet with sodium bicarbonate (baking soda) or sodium citrate, but these substances do not treat the cause of Leigh syndrome. Dichloroacetate may also be effective in treating Leigh syndrome-associated lactic acidosis; research is ongoing on this substance. Coenzyme Q10 supplements have been seen to improve symptoms in some cases.

Clinical trials of the drug EPI-743 for Leigh disease are ongoing.

In 2016, John Zhang and his team at New Hope Fertility Center in New York, USA, performed a spindle transfer mitochondrial donation technique on a mother in Mexico who was at risk of producing a baby with Leigh disease. A healthy boy was born on 6 April 2016. However, it is not yet certain if the technique is completely reliable and safe.

There is no known cure to DSMA1, and care is primarily supportive. Patients require respiratory support which may include non-invasive ventilation or tracheal intubation. The child may also undergo additional immunisations and offered antibiotics to prevent respiratory infections. Maintaining a healthy weight is also important. Patients are at risk of undernutrition and weight loss because of the increased energy spent for breathing. Physical and occupational therapy for the child can be very effective in maintaining muscle strength.

There is no published practice standard for the care in DSMA1, even though the Spinal Muscular Atrophy Standard of Care Committee has been trying to come to a consensus on the care standards for DSMA1 patients. The discrepancies in the practitioners’ knowledge, family resources, and differences in patient’s culture and/or residency have played a part in the outcome of the patient.

Currently there is no curative treatment for KSS. Because it is a rare condition, there are only case reports of treatments with very little data to support their effectiveness. Several promising discoveries have been reported which may support the discovery of new treatments with further research. Satellite cells are responsible for muscle fiber regeneration. It has been noted that mutant mtDNA is rare or undetectable in satellite cells cultured from patients with KSS. Shoubridge et al. (1997) asked the question whether wildtype mtDNA could be restored to muscle tissue by encouraging muscle regeneration. In the forementioned study, regenerating muscle fibers were sampled at the original biopsy site, and it was found that they were essentially homoplasmic for wildtype mtDNA. Perhaps with future techniques of promoting muscle cell regeneration and satellite cell proliferation, functional status in KSS patients could be greatly improved.

One study described a patient with KSS who had reduced serum levels of coenzyme Q10. Administration of 60–120 mg of Coenzyme Q10 for 3 months resulted in normalization of lactate and pyruvate levels, improvement of previously diagnosed first degree AV block, and improvement of ocular movements.

A screening ECG is recommended in all patients presenting with CPEO. In KSS, implantation of pacemaker is advised following the development of significant conduction disease, even in asymptomatic patients.

Screening for endocrinologic disorders should be performed, including measuring serum glucose levels, thyroid function tests, calcium and magnesium levels, and serum electrolyte levels. Hyperaldosteronism is seen in 3% of KSS patients.

NARP syndrome is not curable. Symptomatic relief is targeted. Antioxidants play a role in improving the oxidative phosphorylation that is otherwise impaired.

Although research is ongoing, treatment options are currently limited; vitamins are frequently prescribed, though the evidence for their effectiveness is limited.

Pyruvate has been proposed in 2007 as a treatment option. N-acetyl cysteine reverses many models of mitochondrial dysfunction.. In the case of mood disorders, specifically bipolar disorder, it is hypothesized that N-acetyl-cysteine (NAC), acetyl-L-carnitine (ALCAR), S-adenosylmethionine (SAMe), coenzyme Q10 (CoQ10), alpha-lipoic acid (ALA), creatine monohydrate (CM), and melatonin could be potential treatment options.

The malabsorption resulting from lack of bile acid has resulted in elemental formula being suggested, which are low in fat with < 3% of calories derived from long chain triglycerides (LCT). However, reduced very long chain fatty acids (VLCFA) has not been shown to reduce blood VLCFA levels , likely because humans can endogenously produce most VLCFA. Plasma VLCFA levels are decreased when dietary VLCFA is reduced in conjunction with supplementation of Lorenzo’s oil (a 4:1 mixture of glyceryl trioleate and glyceryl trierucate) in X-ALD patients . Since docosahexaenoic acid (DHA) synthesis is impaired [59], DHA supplementation was recommended, but a placebo-controlled study has since showed no clinical efficacy . Due to the defective bile acid synthesis, fat soluble supplements of vitamins, A, D, E, and K are recommended.

On April 27, 2017, the U.S. Food and Drug Administration approved Brineura (cerliponase alfa) as the first specific treatment for NCL. Brineura is enzyme replacement therapy manufactured through recombinant DNA technology. The active ingredient in Brineura, cerliponase alpha, is intended to slow loss of walking ability in symptomatic pediatric patients 3 years of age and older with late infantile neuronal ceroid lipofuscinosis type 2 (CLN2), also known as tripeptidyl peptidase-1 (TPP1) deficiency. Brineura is administered into the cerebrospinal fluid by infusion via a surgically implanted reservoir and catheter in the head (intraventricular access device).

There is currently no cure or standard procedure for treatment. A bone marrow transplant has been attempted on a child, but it made no improvement. Hydrocephalus may be seen in younger patients and can be relieved with surgery or by implanting a shunt to relieve pressure.

A painkiller available in several European countries, Flupirtine, has been suggested to possibly slow down the progress of NCL, particularly in the juvenile and late infantile forms. No trial has been officially supported in this venue, however. Currently the drug is available to NCL families either from Germany, Duke University Medical Center in Durham, North Carolina, and the Hospital for Sick Children in Toronto, Ontario.

Treatment is limited. Drugs can alleviate the symptoms, such as sleep difficulties and epilepsy. Physiotherapy helps affected children retain the ability to remain upright for as long as possible, and prevents some of the pain.

Recent attempts to treat INCL with cystagon have been unsuccessful.

The treatment of genetic disorders is an ongoing battle with over 1800 gene therapy clinical trials having been completed, are ongoing, or have been approved worldwide. Despite this, most treatment options revolve around treating the symptoms of the disorders in an attempt to improve patient quality of life.

Gene therapy refers to a form of treatment where a healthy gene is introduced to a patient. This should alleviate the defect caused by a faulty gene or slow the progression of disease. A major obstacle has been the delivery of genes to the appropriate cell, tissue, and organ affected by the disorder. How does one introduce a gene into the potentially trillions of cells which carry the defective copy? This question has been the roadblock between understanding the genetic disorder and correcting the genetic disorder.

The treatment of 2-Hydroxyglutaric aciduria is based on seizure control, the prognosis depends on how severe the condition is.

In terms of treatment for short-chain acyl-CoA dehydrogenase deficiency, some individuals may not need treatment, while others might follow administration of:

- Riboflavin

- Dextrose

- Anticonvulsants

Cardiac and respiratory complications are treated symptomatically. Physical and occupational therapy may be beneficial for some patients. Alterations in diet may provide temporary improvement but will not alter the course of the disease. Genetic counseling can provide families with information regarding risk in future pregnancies.

On April 28, 2006 the US Food and Drug Administration approved a Biologic License Application (BLA) for Myozyme (alglucosidase alfa, rhGAA), the first treatment for patients with Pompe disease, developed by a team of Duke University researchers. This was based on enzyme replacement therapy using biologically active recombinant human alglucosidase alfa produced in Chinese Hamster Ovary cells. Myozyme falls under the FDA Orphan Drug designation and was approved under a priority review.

The FDA has approved Myozyme for administration by intravenous infusion of the solution. The safety and efficacy of Myozyme were assessed in two separate clinical trials in 39 infantile-onset patients with Pompe disease ranging in age from 1 month to 3.5 years at the time of the first infusion. Myozyme treatment clearly prolongs ventilator-free survival and overall survival. Early diagnosis and early treatment leads to much better outcomes. The treatment is not without side effects which include fever, flushing, skin rash, increased heart rate and even shock; these conditions, however, are usually manageable.

Myozyme costs an average of US$300,000 a year and must be taken for the patients' entire life, so some American insurers have refused to pay for it. On August 14, 2006, Health Canada approved Myozyme for the treatment of Pompe disease. On June 14, 2007 the Canadian Common Drug Review issued their recommendations regarding public funding for Myozyme therapy. Their recommendation was to provide funding to treat a very small subset of Pompe patients (Infants less one year of age with cardiomyopathy). Genzyme received broad approval in the European Union. On May 26, 2010 FDA approved Lumizyme, a similar version of Myozyme, for the treament of late-onset Pompe disease.

A new treatment option for this disease is called Lumizyme. Lumizyme and Myozyme have the same generic ingredient (Alglucosidase Alfa) and manufacturer (Genzyme Corporation). The difference between these two products is in the manufacturing process. Today, the Myozyme is made using a 160-L bioreactor, while the Lumizyme uses a 4000-L bioreactor. Because of the difference in the manufacturing process, the FDA claims that the two products are biologically different. Moreover, Lumizyme is FDA approved as replacement therapy for late-onset (noninfantile) Pompe disease without evidence of cardiac hypertrophy in patients 8 years and older. Myozyme is FDA approved for replacement therapy for infantile-onset Pompe disease.

Recent studies on chaperone molecules to be used with myozyme are starting to show promising results on animal models.

No treatment is available for most of these disorders. Mannose supplementation relieves the symptoms in PMI-CDG (CDG-Ib) for the most part, even though the hepatic fibrosis may persist. Fucose supplementation has had a partial effect on some SLC35C1-CDG (CDG-IIc or LAD-II) patients.

As of 2017, data on optimal treatment was limited. Therapies with hormones is the standard of care, namely adrenocorticotrophic hormone (ACTH), or oral

corticosteroids such as prednisone. Vigabatrin is also a common consideration, though there is a risk of visual field loss with long term use. The high cost of ACTH leads doctors to avoid it in the US; higher dose prednisone appears to generate equivalent outcomes.

As of 2017 data from clinical trials of the ketogenic diet for treating infantile spams was inconsistent; most trials were as a second-line therapy after failure of drug treatment, and as of 2017 it had not been explored as a first line treatment in an adequately designed clinical trial.

Spindle transfer, where the nuclear DNA is transferred to another healthy egg cell leaving the defective mitochondrial DNA behind, is a potential treatment procedure that has been successfully carried out on monkeys. Using a similar pronuclear transfer technique, researchers at Newcastle University led by Douglass Turnbull successfully transplanted healthy DNA in human eggs from women with mitochondrial disease into the eggs of women donors who were unaffected. In such cases, ethical questions have been raised regarding biological motherhood, since the child receives genes and gene regulatory molecules from two different women. Using genetic engineering in attempts to produce babies free of mitochondrial disease is controversial in some circles and raises important ethical issues. A male baby was born in Mexico in 2016 from a mother with Leigh syndrome using spindle transfer.

In September 2012 a public consultation was launched in the UK to explore the ethical issues involved. Human genetic engineering was used on a small scale to allow infertile women with genetic defects in their mitochondria to have children.

In June 2013, the United Kingdom government agreed to develop legislation that would legalize the 'three-person IVF' procedure as a treatment to fix or eliminate mitochondrial diseases that are passed on from mother to child. The procedure could be offered from 29 October 2015 once regulations had been established.

Embryonic mitochondrial transplant and protofection have been proposed as a possible treatment for inherited mitochondrial disease, and allotopic expression of mitochondrial proteins as a radical treatment for mtDNA mutation load.

Currently, human clinical trials are underway at GenSight Biologics (ClinicalTrials.gov # NCT02064569) and the University of Miami (ClinicalTrials.gov # NCT02161380) to examine the safety and efficacy of mitochondrial gene therapy in Leber's hereditary optic neuropathy.

There is no known cure for microcephaly. Treatment is symptomatic and supportive.

Treatments for Glycerol Kinase Deficiency are targeted to treat the symptoms because there are no permanent treatments for this disease. The main way to treat these symptoms is by using corticosteroids, glucose infusion, or mineralocorticoids. Corticosteroids are steroid hormones that are naturally produced in the adrenal glands. These hormones regulate stress responses, carbohydrate metabolism, blood electrolyte levels, as well as other uses. The mineralocorticoids, such as aldosterone control many electrolyte levels and allow the kidneys to retain sodium. Glucose infusion is coupled with insulin infusion to monitor blood glucose levels and keep them stable.

Due to the multitude of varying symptoms of this disease, there is no specific treatment that will cure this disease altogether. The symptoms can be treated with many different treatments and combinations of medicines to try to find the correct combination to offset the specific symptoms. Everyone with Glycerol Kinase Deficiency has varying degrees of symptoms and thereby requires different medicines to be used in combination to treat the symptoms; however, this disease is not curable and the symptoms can only be managed, not treated fully.