Individuals presenting with Type III galactosemia must consume a lactose- and galactose-restricted diet devoid of dairy products and mucilaginous plants. Dietary restriction is the only current treatment available for GALE deficiency. As glycoprotein and glycolipid metabolism generate endogenous galactose, however, Type III galactosemia may not be resolved solely through dietary restriction.

Treatment of adenylosuccinate lyase deficiency can be done via epilepsy management with anticonvulsive drugs.Additionally the following options include:

- D-ribose and uridine administration

- Ketogenic diet

- S-adenosyl-l-methionine

Currently, the most common form of treatment for SLOS involves dietary cholesterol supplementation. Anecdotal reports indicate that this has some benefits; it may result in increased growth, lower irritability, improved sociability, less self-injurious behaviour, less tactile defensiveness, fewer infections, more muscle tone, less photosensitivity and fewer autistic behaviours. Cholesterol supplementation begins at a dose of 40–50 mg/kg/day, increasing as needed. It is administered either through consuming foods high in cholesterol (eggs, cream, liver), or as purified food grade cholesterol. Younger children and infants may require tube feeding. However, dietary cholesterol does not reduce the levels of 7DHC, cannot cross the blood–brain barrier, and does not appear to improve developmental outcomes. One empirical study found that cholesterol supplementation did not improve developmental delay, regardless of the age at which it began. This is likely because most developmental delays stem from malformations of the brain, which dietary cholesterol cannot ameliorate due to its inability to cross the blood–brain barrier.

HMG-CoA reductase inhibitors have been examined as treatment for SLOS. Given that this catalyzes the rate-limiting step in cholesterol synthesis, inhibiting it would reduce the buildup of toxic metabolites such as 7DHC. Simvastatin is a known inhibitor of HMG-CoA reductase, and most importantly is able to cross the blood–brain barrier. It has been reported to decrease the levels of 7DHC, as well as increase the levels of cholesterol. The increased cholesterol levels are due to simvastatin's effect on the expression of different genes. Simvastatin increases the expression of "DHCR7", likely leading to increased activity of DHCR7. It has also been shown to increase the expression of other genes involved in cholesterol synthesis and uptake. However, these benefits are dependent on the amount of residual cholesterol synthesis. Because some individuals possess less severe mutations and demonstrate some amount of DCHR7 activity, these people benefit the most from simvastatin therapy as they still have a partially functioning enzyme. For individuals that show no residual DCHR7 activity, such as those homozygous for null alleles or mutations, simvastatin therapy may actually be toxic. This highlights the importance of identifying the specific genotype of the SLOS patient before administering treatment. It is still unknown if simvastatin will improve the behavioural or learning deficits in SLOS.

There is no treatment for MKD. But, the inflammation and the other effects can be reduced to a certain extent.

- IL-1 targeting drugs can be used to reduce the effects of the disorder. Anakinra is antagonist to IL-1 receptors. Anakinra binds the IL-1 receptor, preventing the actions of both IL-1α and IL-1β, and it has been proved to reduce the clinical and biochemical inflammation in MKD. It can effectively decreases the frequency as well as the severity of inflammatory attacks when used on a daily basis. Disadvantages with the usage of this drug are occurrence of painful injection site reaction and as the drug is discontinued in the near future the febrile attacks start. (Examined in a 12-year-old patient).

- Canakinumab is a long acting monoclonal antibody which is directed against IL-1β has shown to be effective in reducing both frequency and severity in patients suffering from mild and severe MKD in case reports and observational case series. It reduces the physiological effects but the biochemical parameter still remain elevated (Galeotti et al. demonstrated that it is more effective than anakinra –considered 6 patients suffering from MKD).

- Anti-TNF therapy might be effective in MKD, but the effect is mostly partial and therapy failure and clinical deterioration have been described frequently in patients on infliximab or etanercept. A beneficial effect of human monoclonal anti-TNFα antibody adalimumab was seen in a small number of MKD patients.

- Most MKD patients are benefited by anti-IL-1 therapy. However, anti-IL-1-resistant disease may also occur. Example. tocilizumab (a humanized monoclonal antibody against the interleukin-6 (IL-6) receptor). This drug is used when the patients are unresponsive towards Anakinra. (Shendi et al. treated a young woman in whom anakinra was ineffective with tocilizumab). It was found that it was effective in reducing the biochemical and clinical inflammation [30].Stoffels et al. observed reduction of frequency and severity of the inflammatory attacks, although after several months of treatment one of these two patients persistently showed mild inflammatory symptoms in the absence of biochemical inflammatory markers.

- A beneficial effect of hematopoietic stem cell transplantation can be used in severe mevalonate kinase deficiency conditions (Improvement of cerebral myelinisation on MRI after allogenic stem cell transplantation was observed in one girl). But, liver transplantation did not influence febrile attacks in this patient.

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.

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.

The disorder is treated by strictly reducing the intake of foods rich in plant sterols (e.g., vegetable oils, olives and avocados). However, dietary therapy is often never fully sufficient to control this disease since plant sterols are constituents of all plant-based foods. Statins have been used, and while these lower cholesterol levels and may ameliorate atherosclerotic disease, plant sterol levels are insufficiently lowered by their use alone.

If dietary treatment alone is insufficient, bile acid-binding resins (e.g., cholestyramine, colestipol) could be considered. In October 2002, a new cholesterol absorption inhibitor, ezetimibe, received US Food and Drug Administration (FDA) approval for use in sitosterolemia. This drug is now the standard of care, as it blocks sterol entry and can be used in combination with bile-acid resins.

Finally, ileal bypass has been performed in select cases to decrease the levels of plant sterols in the body, though this therapy was undertaken prior to the advent of ezetimibe.

Since phytanic acid is not produced in the human body, individuals with Refsum disease are commonly placed on a phytanic acid-restricted diet and avoid the consumption of fats from ruminant animals and certain fish, such as tuna, cod, and haddock. Grass feeding animals and their milk are also avoided. Recent research has shown that CYP4 isoform enzymes could help reduce the over-accumulation of phytanic acid "in vivo". Plasmapheresis is another medical intervention used to treat patients. This involves the filtering of blood to ensure there is no accumulation of phytanic acid.

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.

The prognosis of this condition in childhood usually has a stable outcome, whereas in neonatal is almost always fatal, according to Jurecka, et al.

In ruminant animals, the gut fermentation of consumed plant materials liberates phytol, a constituent of chlorophyll, which is then converted to phytanic acid and stored in fats. Although humans cannot derive significant amounts of phytanic acid from the consumption of chlorophyll present in plant materials, it has been proposed that the great apes (bonobos, chimpanzees, gorillas, and orangutans) can derive significant amounts of phytanic acid from the hindgut fermentation of plant materials.

There is no treatment for the disorder. A number of studies are looking at gene therapy, exon skipping and CRISPR interference to offer hope for the future. Accurate determination through confirmed diagnosis of the genetic mutation that has occurred also offers potential approaches beyond gene replacement for a specific group, namely in the case of diagnosis of a so-called nonsense mutation, a mutation where a stop codon is produced by the changing of a single base in the DNA sequence. This results in premature termination of protein biosynthesis, resulting in a shortened and either functionless or function-impaired protein. In what is sometimes called "read-through therapy", translational skipping of the stop codon, resulting in a functional protein, can be induced by the introduction of specific substances. However, this approach is only conceivable in the case of narrowly circumscribed mutations, which cause differing diseases.

Infant mortality is high for patients diagnosed with early onset; mortality can occur within less than 2 months, while children diagnosed with late-onset syndrome seem to have higher rates of survival. Patients suffering from a complete lesion of mut0 have not only the poorest outcome of those suffering from methylaonyl-CoA mutase deficiency, but also of all individuals suffering from any form of methylmalonic acidemia.

Until more molecular and clinical studies are performed there will be no way to prevent the disease. Treatments are directed towards alleviating the symptoms. To treat the disease it is crucial to diagnose it properly. Orthopedic therapy and fracture management are necessary to reduce the severity of symptoms. Bisphosphonate drugs are also an effective treatment.

Prognosis is good, and treatment of this syndrome is usually unnecessary. Most patients are asymptomatic and have normal lifespans. Some neonates present with cholestasis. Hormonal contraceptives and pregnancy may lead to overt jaundice and icterus (yellowing of the eyes and skin).

Several tests can be done to discover the dysfunction of methylmalonyl-CoA mutase. Ammonia test, blood count, CT scan, MRI scan, electrolyte levels, genetic testing, methylmalonic acid blood test, and blood plasma amino acid tests all can be conducted to determine deficiency.

There is no treatment for complete lesion of the mut0 gene, though several treatments can help those with slight genetic dysfunction. Liver and kidney transplants, and a low-protein diet all help regulate the effects of the diseases.

In 2009, Monash Children's Hospital at Southern Health in Melbourne, Australia reported that a patient known as Baby Z became the first person to be successfully treated for molybdenum cofactor deficiency type A. The patient was treated with cPMP, a precursor of the molybdenum cofactor. Baby Z will require daily injections of cyclic pyranopterin monophosphate (cPMP) for the rest of her life.

Persons with the genotype for PKU are unaffected in utero, because maternal circulation prevents buildup of [phe]. After birth, PKU in newborns is treated by a special diet with highly restricted phenylalanine content. Persons with genetic predisposition to PKU have normal mental development on this diet. Previously, it was thought safe to withdraw from the diet in the late teens or early twenties, after the central nervous system was fully developed; recent studies suggest some degree of relapse, and a continued phenylalanine-restricted diet is now recommended.

PKU or hyperphenylalaninemia may also occur in persons without the PKU genotype. If the mother has the PKU genotype but has been treated so as to be asymptomatic, high levels of [phe] in the maternal blood circulation may affect the non-PKU fetus during gestation. Mothers successfully treated for PKU are advised to return to the [phe]-restricted diet during pregnancy.

A small subset of patients with hyperphenylalaninemia shows an appropriate reduction in plasma phenylalanine levels with dietary restriction of this amino acid; however, these patients still develop progressive neurologic symptoms and seizures and usually die within the first 2 years of life ("malignant" hyperphenylalaninemia). These infants exhibit normal phenylalanine hydroxylase (PAH) enzymatic activity but have a deficiency in dihydropteridine reductase (DHPR), an enzyme required for the regeneration of tetrahydrobiopterin (THB or BH), a cofactor of PAH.

Less frequently, DHPR activity is normal but a defect in the biosynthesis of THB exists. In either case, dietary therapy corrects the hyperphenylalaninemia. However, THB is also a cofactor for two other hydroxylation reactions required in the syntheses of neurotransmitters in the brain: the hydroxylation of tryptophan to 5-hydroxytryptophan and of tyrosine to L-dopa. It has been suggested that the resulting deficit in the CNS neurotransmitter activity is, at least in part, responsible for the neurologic manifestations and eventual death of these patients.

Galactose epimerase deficiency, also known as GALE deficiency, Galactosemia III and UDP-galactose-4-epimerase deficiency, is a rare, autosomal recessive form of galactosemia associated with a deficiency of the enzyme "galactose epimerase".

Treatments for ichthyosis often take the form of topical application of creams and emollient oils, in an attempt to hydrate the skin. Creams containing lactic acid have been shown to work exceptionally well in some cases. Application of propylene glycol is another treatment method. Retinoids are used for some conditions.

Exposure to sunlight may improve or worsen the condition. In some cases, excess dead skin sloughs off much better from wet tanned skin after bathing or a swim, although the dry skin might be preferable to the damaging effects of sun exposure.

There can be ocular manifestations of ichthyosis, such as corneal and ocular surface diseases. Vascularizing keratitis, which is more commonly found in congenital keratitis-ichythosis-deafness (KID), may worsen with isotretinoin therapy.

There is no cure for HCP caused by the deficient activity of coproporphyrinogen oxidase. Treatment of the acute symptoms of HCP is the same as for other acute porphyrias. Intravenous hemin (as heme arginate or hematin) is the recommended therapy for acute attacks. Acute attacks can be severe enough to cause death if not treated quickly and correctly. Hospitalization is typically required for administration of hemin, and appropriate drug selection is key to avoid exacerbating symptoms with drugs that interact poorly with porphyrias. Proper drug selection is most difficult when it comes to treatment of the seizures that can accompany HCP, as most anti-seizure medications can make the symptoms worse. Gabapentin and levetiracetam are two anti-seizure drugs that are thought to be safe.

In patients where management of symptoms is difficult even with hemin, liver transplant is an option before the symptoms have progressed to advanced paralysis. Combined liver and kidney transplants are sometimes undertaken in patients with renal failure.

Long term treatment of acute porphyrias is centered on the avoidance of acute attacks by eliminating precipitating factors, such as drugs, dietary changes, and infections. Females often have attacks coincident with their menstrual cycle, which can be managed effectively with hormonal birth control. Because of the reduced penetrance of HCP, family members of a patient may carry the same mutation without ever presenting with symptoms. Molecular analysis of "CPOX" is the best way to identify these patients, as they will not express a biochemical phenotype on laboratory testing unless they are symptomatic. Identification of asymptomatic patients allows them to adjust their lifestyle to avoid common triggering factors.

A disease that threatens the eyesight and additionally produces a hair anomaly that is apparent to strangers causes harm beyond the physical. It is therefore not surprising that learning the diagnosis is a shock to the patient. This is as true of the affected children as of their parents and relatives. They are confronted with a statement that there are at present no treatment options. They probably have never felt so alone and abandoned in their lives. The question comes to mind, "Why me/my child?" However, there is always hope and especially for affected children, the first priority should be a happy childhood. Too many examinations and doctor appointments take up time and cannot practically solve the problem of a genetic mutation within a few months. It is therefore advisable for parents to treat their child with empathy, but to raise him or her to be independent and self-confident by the teenage years. Openness about the disease and talking with those affected about their experiences, even though its rarity makes it unlikely that others will be personally affected by it, will together assist in managing life.

At present, no specific enzyme deficiency nor genetic mutation has been implicated as the cause of hypertryptophanemia. Several known factors regarding tryptophan metabolism and kynurenines, however, may explain the presence of behavioral abnormalities seen with the disorder.

Tryptophan is an essential amino acid, and is required for protein synthesis. Aside from this crucial role, the remainder of tryptophan is primarily metabolized along the kynurenine pathway in most tissues, including those of the brain and central nervous system.

As the main defect behind hypertryptophanemia is suspected to alter and disrupt the metabolic pathway from tryptophan to kynurenine, a possible correlation between hypertryptophanemia and the known effects of kynurenines on neuronal function, physiology and behavior may be of interest.

One of these kynurenines, aptly named kynurenic acid, serves as a neuroprotectant through its function as an antagonist at both nicotinic and glutamate receptors (responsive to the neurotransmitters nicotine and glutamate, respectively). This action is in opposition to the agonist quinolinic acid, another kynurenine, noted for its potential as a neurotoxin. Quinolinic acid activity has been associated with neurodegenerative disorders such as Huntington's disease, the neuroprective abilities of kynurenic acid forming a counterbalance against this process, and the related excitotoxicity and similar damaging effects on neurons.

Indoleic acid excretion is another indicator of hypertryptophanemia. Indirectly related to kynurenine metabolism, indole modifies neural function and human behavior by interacting with voltage-dependent sodium channels (integral membrane proteins that form ion channels, allowing vital synaptic action potentials).

Canakinumab has been approved for treatment of HIDS and has shown to be effective. The immunosuppressant drugs etanercept and anakinra have also shown to be effective. Statin drugs might decrease the level of mevalonate and are presently being investigated. A recent single case report highlighted bisphosphonates as a potential therapeutic option.