The treatment approaches focus to restore depleted brain creatine with creatine supplementation in pharmacologic doses. All patients are reported to benefit by this treatment, with improvements in muscular hypotonia, dyskinesia, social contact, alertness and behavior. Seizures appear to reduce more with dietary arginine restriction and ornithine supplementation. Despite treatment, none of the patients have been reported to return to completely normal developmental level.

A cure does not exist for I-Cell disease/Mucolipidosis II disease. Treatment is limited to controlling or reducing the symptoms that are associated with this disorder. Nutritional supplements, particularly iron and vitamin B12, are often recommended for individuals with I-Cell disease. Physical therapy to improve motor delays and speech therapy to improve language acquisition are treatment options. Surgery can remove the thin layer of corneal clouding to temporarily improve the complication. It is possible that bone marrow transplant may be helpful in delaying or correcting the neurological deterioration that occurs with I-Cell disease.. Even though there is no existing treatment, the Yash Gandhi Foundation is a 501(c)(3) non-profit organization focused on funding research for I-Cell disease

At this time there is no treatment for transaldolase deficiency.

There is currently research being done to find treatments for transaldolase deficiency. A study done in 2009 used orally administered N-acetylcysteine on transaldolase deficient mice and it prevented the symptoms associated with the disease. N-acetylcysteine is a precursor for reduced glutathione, which is decreased in transaldolase deficient patients.

Low-protein food is recommended for this disorder, which requires food products low in particular types of amino acids (e.g., methionine).

No specific cure has been discovered for homocystinuria; however, many people are treated using high doses of vitamin B (also known as pyridoxine). Slightly less than 50% respond to this treatment and need to take supplemental vitamin B for the rest of their lives. Those who do not respond require a Low-sulfur diet (especially monitoring methionine), and most will need treatment with trimethylglycine. A normal dose of folic acid supplement and occasionally adding cysteine to the diet can be helpful, as glutathione is synthesized from cysteine (so adding cysteine can be important to reduce oxidative stress).

Betaine (N,N,N-trimethylglycine) is used to reduce concentrations of homocysteine by promoting the conversion of homocysteine back to methionine, i.e., increasing flux through the re-methylation pathway independent of folate derivatives (which is mainly active in the liver and in the kidneys).The re-formed methionine is then gradually removed by incorporation into body protein. The methionine that is not converted into protein is converted to S-adenosyl-methionine which goes on to form homocysteine again. Betaine is, therefore, only effective if the quantity of methionine to be removed is small. Hence treatment includes both betaine and a diet low in methionine. In classical homocystinuria (CBS, or cystathione beta synthase deficiency), the plasma methionine level usually increases above the normal range of 30 micromoles/L and the concentrations should be monitored as potentially toxic levels (more than 400 micromoles/L) may be reached.

Although there is currently no cure, treatment includes injections of structurally similar compound, N-Carbamoyl-L-glutamate, an analogue of N-Acetyl Glutamate. This analogue likewise activates CPS1. This treatment mitigates the intensity of the disorder.

If symptoms are detected early enough and the patient is injected with this compound, levels of severe mental retardation can be slightly lessened, but brain damage is irreversible.

Early symptoms include lethargy, vomiting, and deep coma.

The conversion of tryptophan to serotonin and other metabolites depends on vitamin B. If tryptophan catabolism has any impact on brain glutaric acid and other catabolite levels, vitamin B levels should be routinely assayed and normalized in the course of the treatment of GA1.

Dietary control may help limit progression of the neurological damage.

There is no cure for Salla disease. Treatment is limited to controlling the symptoms of this disorder. Anti-convulsant medication may control seizure episodes. Physical therapists can assist an affected individual to build muscle strength and coordination.

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.

Administration of cytidine monophosphate and uridine monophosphate reduces urinary orotic acid and ameliorates the anemia.

Administration of uridine, which is converted to UMP, will bypass the metabolic block and provide the body with a source of pyrimidine.

Uridine triacetate is a drug approved by FDA to be used in the treatment of hereditary orotic aciduria.

There is no cure for Pseudo-Hurler Polydystrophy/Mucolipidosis IIIA. Treatment is limited to controlling or reducing symptoms associated with this disorder. Physio-therapy, particularly hydrotherapy has proven effective at relieving muscle stiffness and increasing mobility. The use of crutches, a wheelchair or scooters are treatment options as the metabolic bone disease progresses. The insertion of rods in the spine to stabilize the vulnerable areas can treat scoliosis. Heart valve replacement surgery may be necessary as this disorder progresses.

Treatment is depended on the type of glycogen storage disease. E.g. GSD I is typically treated with frequent small meals of carbohydrates and cornstarch to prevent low blood sugar, while other treatments may include allopurinol and human granulocyte colony stimulating factor.

There is no cure for Canavan disease, nor is there a standard course of treatment. Treatment is symptomatic and supportive. There is also an experimental treatment using lithium citrate. When a person has Canavan disease, his or her levels of N-acetyl aspartate are chronically elevated. The lithium citrate has proven in a rat genetic model of Canavan disease to be able to significantly decrease levels of N-acetyl aspartate. When tested on a human, the subject's condition reversed during a two-week wash-out period after withdrawal of lithium.

The investigation revealed both decreased N-acetyl aspartate levels in regions of the brain tested and magnetic resonance spectroscopic values that are more characteristic of normal development and myelination. This evidence suggests that a larger controlled trial of lithium may be warranted as supportive therapy for children with Canavan disease.

Experimental gene therapy trial results, published in 2002, used a healthy gene to take over for the defective one that causes Canavan disease.

In human trials, the results of which were published in 2012, this method appeared to improve the life of the patient without long-term adverse effects during a 5-year follow-up.

Since PCT is a chronic condition, a comprehensive management of the disease is the most effective means of treatment. Primarily, it is key that patients diagnosed with PCT avoid alcohol consumption, iron supplements, excess exposure to sunlight (especially in the summer), as well as estrogen and chlorinated cyclic hydrocarbons, all of which can potentially exacerbate the disorder. Additionally, the management of excess iron (due to the commonality of hemochromatosis in PCT patients) can be achieved through phlebotomy, whereby blood is systematically drained from the patient. A borderline iron deficiency has been found to have a protective affect by limiting heme synthesis. In the absence of iron, which is to be incorporated in the porphyrin formed in the last step of the synthesis, the mRNA of erythroid 5-aminolevulinate synthase (ALAS-2) is blocked by attachment of an iron-responsive element (IRE) binding cytosolic protein, and transcription of this key enzyme is inhibited.

Low doses of antimalarials can be used. Orally ingested chloroquine is completely absorbed in the gut and is preferentially concentrated in the liver, spleen, and kidneys. They work by removing excess porphyrins from the liver via increasing the excretion rate by forming a coordination complex with the iron center of the porphyrin as well as an intramolecular hydrogen bond between a propionate side chain of the porphyrin and the protonated quinuclidine nitrogen atom of either alkaloid. Due to the presence of the chlorine atom, the entire complex is more water soluble allowing the kidneys to preferentially remove it from the blood stream and expel it through urination. It should be noted that chloroquine treatment can induce porphyria attacks within the first couple of months of treatment due to the mass mobilization of porphyrins from the liver into the blood stream. Complete remission can be seen within 6–12 months as each dose of antimalarial can only remove a finite amount of porphyrins and there are generally decades of accumulation to be cleared. Originally, higher doses were used to treat the condition but are no longer recommended because of liver toxicity. Finally, due to the strong association between PCT and Hepatitis C, the treatment of Hepatitis C (if present) is vital to the effective treatment of PCT.

Chloroquine, hydroxychloroquine, and venesection are typically employed in the management strategy.

There is no known cure or treatment for the disorder.

The metabolic and clinical manifestations of TMAU are generally regarded as benign, as there is no associated organ dysfunction. This

designation, and the fact that the condition is often unrecognised by doctors, can have important ramifications including missed or delayed diagnosis.

Affected individuals experience shame and embarrassment, fail to maintain relationships, avoid contact with people who comment on their condition, and are obsessive about masking the odour with hygiene products and even smoking. The malodorous aspect can have serious and destructive effects on schooling, personal life, career and relationships, resulting in social isolation, low self-esteem, depression, paranoid behaviour, and suicide. Delayed diagnosis, body odour and the lack of cure may lead to psychosocial issues. When the condition is suspected or known to occur in a family, genetic testing can be helpful in identifying the specific individuals who have or carry the disorder.

Ways of reducing the fishy odor may include:

- Avoiding foods such as egg yolks, legumes, red meats, fish, beans and other foods that contain choline, carnitine, nitrogen, sulfur and lecithin

- Taking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gut

- Using slightly acidic detergent with a pH between 5.5 and 6.5

Additionally, at least one study has suggested that daily intake of the supplements activated charcoal and copper chlorophyllin may improve the quality of life of individuals afflicted with TMAU by helping their bodies to oxidize and convert TMA to the odorless "N"-oxide (TMAO) metabolite. Study participants experienced subjective reduction in odor as well as objective reduction in TMA and increase in TMAO concentration measured in their urine. The study found that:

- 85% of test participants experienced complete loss of detectable "fishy" odor

- 10% experienced some reduction in detectable odor

- 5% did not experience any detectable odor reduction

Long term management is by use of anticonvulsant medication, principally valproate, stiripentol, topiramate or clobazam. Ketogenic diet has also been found useful in certain cases

Management of breakthrough seizures is by benzodiazepine such as midazolam.

There have been no major breakthroughs in the treatment of PKAN, with most pharmacologic treatments focusing on the easing or temporary relieving of PKAN’s symptoms. Iron chelating agents have been used somewhat successfully in retarding the disorder, but they have not been a significant success.

Current research focuses on the future use of high dose pantothenate, the PANK2 enzyme substrate, in possibly alleviating symptoms as well as the further development of iron chelating agents that may be better aimed at reaching the central nervous system and working to better remove excess iron from the individual’s system.

Complications may result from the medication used to treat symptoms. Immobility from the disease can also lead to skin breakdown, respiratory infections, and blood clots, among others.

Infants with Schindler disease tend to die within 4 years of birth, therefore, treatment for this form of the disease is mostly palliative. However, Type II Schindler disease, with its late onset of symptoms, is not characterized by neurological degeneration. There is no known cure for Schindler disease, but bone marrow transplants have been trialed, as they have been successful in curing other glycoprotein disorders.

The life expectancy for individuals with Salla disease is between the ages of 50 and 60.

While there is no cure for JBS, treatment and management of specific symptoms and features of the disorder are applied and can often be successful. Variability in the severity of JBS on a case-by-case basis determines the requirements and effectiveness of any treatment selected.

Pancreatic insufficiency and malabsorption can be managed with pancreatic enzyme replacement therapy, such as pancrelipase supplementation and other related methods.

Craniofacial and skeletal deformities may require surgical correction, using techniques including bone grafts and osteotomy procedures. Sensorineural hearing loss can be managed with the use of hearing aids and educational services designated for the hearing impaired.

Special education, specialized counseling methods and occupational therapy designed for those with mental retardation have proven to be effective, for both the patient and their families. This, too, is carefully considered for JBS patients.

N-Acetylglutamate synthase (or synthetase) deficiency is an autosomal recessive urea cycle disorder.

Survival rates for those diagnosed with typical PKAN is 11.18 years with a standard deviation of 7.8 years.

D-Bifunctional protein deficiency (officially called 17β-hydroxysteroid dehydrogenase IV deficiency) is an autosomal recessive peroxisomal fatty acid oxidation disorder. Peroxisomal disorders are usually caused by a combination of peroxisomal assembly defects or by deficiencies of specific peroxisomal enzymes. The peroxisome is an organelle in the cell similar to the lysosome that functions to detoxify the cell. Peroxisomes contain many different enzymes, such as catalase, and their main function is to neutralize free radicals and detoxify drugs, such as alcohol. For this reason peroxisomes are ubiquitous in the liver and kidney. D-BP deficiency is the most severe peroxisomal disorder, often resembling Zellweger syndrome.

Characteristics of the disorder include neonatal hypotonia and seizures, occurring mostly within the first month of life, as well as visual and hearing impairment. Other symptoms include severe craniofacial disfiguration, psychomotor delay, and neuronal migration defects. Most onsets of the disorder begin in the gestational weeks of development and most affected individuals die within the first two years of life.

No specific treatment is available. Management is only supportive and preventive.

Those who are diagnosed with the disease often die within the first few months of life. Almost all children with the disease die by the age of three.