If a contracture is less than 30 degrees, it may not interfere with normal functioning. The common treatment is splinting and occupational therapy. Surgery is the last option for most cases as the result may not be satisfactory.

There is no single course of medical treatment or cure for Möbius syndrome. Treatment is supportive and in accordance with symptoms. If they have difficulty nursing, infants may require feeding tubes or special bottles to maintain sufficient nutrition. Physical, occupational, and speech therapy can improve motor skills and coordination and can lead to better control of speaking and eating abilities. Often, frequent lubrication with eye drops is sufficient to combat dry eye that results from impaired blinking. Surgery can correct crossed eyes, protect the cornea via tarsorraphy, and improve limb and jaw deformities. Sometimes called smile surgery by the media, muscle transfers grafted from the thigh to the corners of the mouth can be performed to provide the ability to smile. Although "smile surgery" may provide the ability to smile, the procedure is complex and can take twelve hours for each side of the face. Also, the surgery cannot be considered a "cure" for Möbius syndrome, because it does not improve the ability to form other facial expressions.

Since Usher syndrome results from the loss of a gene, gene therapy that adds the proper protein back ("gene replacement") may alleviate it, provided the added protein becomes functional. Recent studies of mouse models have shown one form of the disease—that associated with a mutation in myosin VIIa—can be alleviated by replacing the mutant gene using a lentivirus. However, some of the mutated genes associated with Usher syndrome encode very large proteins—most notably, the "USH2A" and "GPR98" proteins, which have roughly 6000 amino-acid residues. Gene replacement therapy for such large proteins may be difficult.

Administration of GH has no effect on IGF-1 production, therefore treatment is mainly by biosynthetic IGF-1. IGF-1 must be taken before puberty to be effective.

The drug product Increlex (mecasermin), developed by the company Tercica, now Genentech, was approved by the US Food and Drug Administration in August 2005 for replacing IGF-1 in patients who are deficient.

IPLEX (Mecasermin rinfabate) is composed of recombinant human IGF-1 (rhIGF-1) and its binding protein IGFBP-3. It was approved by the U.S. Food and Drug Administration (FDA) in 2005 for treatment of primary IGF-1 deficiency or GH gene deletion. Side effects from IPLEX are hypoglycemia. IPLEX's manufacturing company, Insmed, after selling its protein production facility, can no longer develop proteins, thus can no longer manufacture IPLEX as of a statement released in July 2009.

The most effective anti-epileptic medication for JME is valproic acid (Depakote). Women are often started on alternative medications due to valproic acid's high incidence of fetal malformations. Lamotrigine, levetiracetam, topiramate, and zonisamide are alternative anti-epileptic medications with less frequent incidence of pregnancy related complications, and they are often used first in females of childbearing age. Carbamazepine may aggravate primary generalized seizure disorders such as JME. Treatment is lifelong. Patients should be warned to avoid sleep deprivation.

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.

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).

On October 20, 2005, the Food and Drug Administration approved a phase I clinical trial of neural stem cells to treat infantile and late infantile Batten disease. Subsequent approval from an independent review board also approved the stem cell therapy in early March 2006. This treatment will be the first ever transplant of fetal stem cells performed on humans. The therapy is being developed by Stem Cells Inc and is estimated to have six patients. The treatment will be carried out in Oregon.

Juvenile NCL has recently been listed on the Federal Clinical Trials website to test the effectiveness of bone marrow/stem cell transplants for this condition. A bone marrow transplant has been attempted in the late infantile form of NCL with disappointing results; while the transplant may have slowed the onset of the disease, the child eventually developed the disease and died in 1998.

Trials testing the effectiveness of bone marrow transplants for infantile NCL in Finland have also been disappointing, with only a slight slowing of disease reported.

The malpositioning seen on radiography may not cause any symptoms at all. If there are related symptoms, however, therapeutic options include chiropractic care, physical therapy and nerve block injections. As a last resort, decompressive laminectomy may be attempted to relieve pain symptoms and remove the abnormally enlarged portions of bone.

The prognosis for individuals with Pompe disease varies according to the onset and severity of symptoms. Without treatment the disease is particularly lethal in infants and young children.

Myozyme (alglucosidase alfa) is a recombinant form of the human enzyme acid alpha-glucosidase, and is also currently being used to replace the missing enzyme. In a study which included the largest cohort of patients with Pompe disease treated with enzyme replacement therapy (ERT) to date findings showed that Myozyme treatment clearly prolongs ventilator-free survival and overall survival in patients with infantile-onset Pompe disease as compared to an untreated historical control population. Furthermore, the study demonstrated that initiation of ERT prior to 6 months of age, which could be facilitated by newborn screening, shows great promise to reduce the mortality and disability associated with this devastating disorder. Taiwan and several states in the United States have started the newborn screening and results of such regimen in early diagnosis and early initiation of the therapy have dramatically improved the outcome of the disease; many of these babies have reached the normal motor developmental milestones.

Another factor affecting the treatment response is generation of antibodies against the infused enzyme, which is particularly severe in Pompe infants who have complete deficiency of the acid alpha-glucosidase. Immune tolerance therapy to eliminate these antibodies has improved the treatment outcome.

A Late Onset Treatment Study (LOTS) was published in 2010. The study was undertaken to evaluate the safety and efficacy of aglucosidase alfa in juvenile and adult patients with Pompe disease. LOTS was a randomized, double-blind, placebo-controlled study that enrolled 90 patients at eight primary sites in the United States and Europe. Participants received either aglucosidase alfa or a placebo every other week for 18 months. The average age of study participants was 44 years. The primary efficacy endpoints of the study sought to determine the effect of Myozyme on functional endurance as measured by the six-minute walk test and to determine the effect of aglucosidase alfa on pulmonary function as measured by percent predicted forced vital capacity.

The results showed that, at 78 weeks, patients treated with aglucosidase alfa increased their distance walked in six minutes by an average of approximately 25 meters as compared with the placebo group which declined by 3 meters (P=0.03). The placebo group did not show any improvement from baseline. The average baseline distance walked in six minutes in both groups was approximately 325 meters.

Percent predicted forced vital capacity in the group of patients treated with aglucosidase alfa increased by 1.2 percent at 78 weeks. In contrast, it declined by approximately 2.2 percent in the placebo group (P=0.006).

Adducted thumb syndrome recessive form is a rare disease affecting multiple systems causing malformations of the palate, thumbs, and upper limbs. The name Christian syndrome derives from Joe. C. Christian, the first person to describe the condition. Inheritance is believed to be autosomal recessive, caused by mutation in the CHST14 (carbohydrate sulfotransferase 14) gene.

This syndrome is associated with microcephaly, arthrogryposis and cleft palate and various craniofacial, respiratory, neurological and limb abnormalities, including bone and joint defects of the upper limbs, adducted thumbs, camptodactyly and talipes equinovarus or calcaneovalgus. It is characterized by craniosynostosis, and myopathy in association with congenital generalized hypertrichosis.

Patients with the disease are considered intellectually disabled. Most die in childhood. Patients often suffer from respiratory difficulties such as pneumonia, and from seizures due to dysmyelination in the brain's white matter. It has been hypothesized that the Moro reflex (startle reflex in infants) may be a tool in detecting the congenital clapsed thumb early in infancy. The thumb normally extends as a result of this reflex.

With rest and quadriceps flexibility exercises the condition settles with no secondary disability. Sometimes, if the condition does not settle, calcification appears in the ligament. This condition is comparable to Osgood-Schlatter’s disease and usually recovers spontaneously. If rest fails to provide relief, the abnormal area is removed and the paratenon is stripped.

Guidelines for management of patients up to 18 years with Langerhans cell histiocytosis has been suggested. Treatment is guided by extent of disease. Solitary bone lesion may be amenable through excision or limited radiation, dosage of 5-10 Gys for children, 24-30 Gys for adults. However systemic diseases often require chemotherapy. Use of systemic steroid is common, singly or adjunct to chemotherapy. Local steroid cream is applied to skin lesions. Endocrine deficiency often require lifelong supplement e.g. desmopressin for diabetes insipidus which can be applied as nasal drop. Chemotherapeutic agents such as alkylating agents, antimetabolites, vinca alkaloids either singly or in combination can lead to complete remission in diffuse disease.

Treatment of Sydenham's Chorea is based on the following principles:

1. The first tenet of treatment is to eliminate the streptococcus at a primary, secondary and tertiary level. Strategies involve the adequate treatment of throat and skin infections, with a course of penicillin when Sydenham's Chorea is newly diagnosed, followed by long-term penicillin prophylaxis. Behavioural and emotional changes may precede the movement disorders in a previously well child.

2. Treatment of movement disorders. Therapeutic efforts are limited to palliation of the movement disorders. Haloperidol is frequently used because of its anti-dopaminergic effect. It has serious potential side-effects, e.g., tardive dyskinesia. In a study conducted at the RFC, 25 out of 39 patients on haloperidol reported side-effects severe enough to cause the physician or parent to discontinue treatment or reduce the dose. Other medications which have been used to control the movements include pimozide, clonidine, valproic acid, carbamazepine and phenobarbitone.

3. Immunomodulatory interventions include steroids, intravenous immunoglobulins, and plasma exchange. Patients may benefit from treatment with steroids; controlled clinical trials are indicated to explore this further.

4. There are several historical case series reporting successful treatment of Sydenham's Chorea by inducing fever.

Currently Sandhoff disease does not have any standard treatment and does not have a cure. However, a person suffering from the disease needs proper nutrition, hydration, and maintenance of clear airways. To reduce some symptoms that may occur with Sandhoff disease, the patient may take anticonvulsants to manage seizures or medications to treat respiratory infections, and consume a precise diet consisting of puree foods due to difficulties swallowing. Infants with the disease usually die by the age of 3 due to respiratory infections. The patient must be under constant surveillance because they can suffer from aspiration or lack the ability to change from the passageway to their lungs versus their stomach and their spit travels to the lungs causing bronchopneumonia. The patient also lacks the ability to cough and therefore must undergo a treatment to shake up their body to remove the mucus from the lining of their lungs. Medication is also given to patients to lessen their symptoms including seizures.

Currently the government is testing several treatments including N-butyl-deoxynojirimycin in mice, as well as stem cell treatment in humans and other medical treatments recruiting test patients.

Möbius syndrome (also spelled Moebius) is an extremely rare congenital neurological disorder which is characterized by facial paralysis and the inability to move the eyes from side to side. Most people with Möbius syndrome are born with complete facial paralysis and cannot close their eyes or form facial expressions. Limb and chest wall abnormalities sometimes occur with the syndrome. People with Möbius syndrome have normal intelligence, although their lack of facial expression is sometimes incorrectly taken to be due to dullness or unfriendliness. It is named for Paul Julius Möbius, a neurologist who first described the syndrome in 1888.

The specific cause of camptodactyly remains unknown, but there are a few deficiencies that lead to the condition. A deficient lumbrical muscle controlling the flexion of the fingers, and abnormalities of the flexor and extensor tendons.

A number of congenital syndromes may also cause camptodactyly:

- Jacobsen syndrome

- Beals Syndrome

- Blau syndrome

- Freeman-Sheldon syndrome

- Cerebrohepatorenal syndrome

- Weaver syndrome

- Christian syndrome 1

- Gordon Syndrome

- Jacobs arthropathy-camptodactyly syndrome

- Lenz microphthalmia syndrome

- Marshall-Smith-Weaver syndrome

- Oculo-dento-digital syndrome

- Tel Hashomer camptodactyly syndrome

- Toriello-Carey syndrome

- Stuve-Wiedemann syndrome

- Loeys-Dietz syndrome

- Fryns syndrome

- Marfan's syndrome

- Carnio-carpo-tarsal dysthropy

By most definitions, intellectual disability is more accurately considered a "disability" rather than a "disease". Intellectual disability can be distinguished in many ways from mental illness, such as schizophrenia or depression. Currently, there is no "cure" for an established disability, though with appropriate support and teaching, most individuals can learn to do many things.

There are thousands of agencies around the world that provide assistance for people with developmental disabilities. They include state-run, for-profit, and non-profit, privately run agencies. Within one agency there could be departments that include fully staffed residential homes, day rehabilitation programs that approximate schools, workshops wherein people with disabilities can obtain jobs, programs that assist people with developmental disabilities in obtaining jobs in the community, programs that provide support for people with developmental disabilities who have their own apartments, programs that assist them with raising their children, and many more. There are also many agencies and programs for parents of children with developmental disabilities.

Beyond that, there are specific programs that people with developmental disabilities can take part in wherein they learn basic life skills. These "goals" may take a much longer amount of time for them to accomplish, but the ultimate goal is independence. This may be anything from independence in tooth brushing to an independent residence. People with developmental disabilities learn throughout their lives and can obtain many new skills even late in life with the help of their families, caregivers, clinicians and the people who coordinate the efforts of all of these people.

There are four broad areas of intervention that allow for active participation from caregivers, community members, clinicians, and of course, the individual(s) with an intellectual disability. These include psychosocial treatments, behavioral treatments, cognitive-behavioral treatments, and family-oriented strategies. Psychosocial treatments are intended primarily for children before and during the preschool years as this is the optimum time for intervention. This early intervention should include encouragement of exploration, mentoring in basic skills, celebration of developmental advances, guided rehearsal and extension of newly acquired skills, protection from harmful displays of disapproval, teasing, or punishment, and exposure to a rich and responsive language environment. A great example of a successful intervention is the Carolina Abecedarian Project that was conducted with over 100 children from low SES families beginning in infancy through pre-school years. Results indicated that by age 2, the children provided the intervention had higher test scores than control group children, and they remained approximately 5 points higher 10 years after the end of the program. By young adulthood, children from the intervention group had better educational attainment, employment opportunities, and fewer behavioral problems than their control-group counterparts.

Core components of behavioral treatments include language and social skills acquisition. Typically, one-to-one training is offered in which a therapist uses a shaping procedure in combination with positive reinforcements to help the child pronounce syllables until words are completed. Sometimes involving pictures and visual aids, therapists aim at improving speech capacity so that short sentences about important daily tasks (e.g. bathroom use, eating, etc.) can be effectively communicated by the child. In a similar fashion, older children benefit from this type of training as they learn to sharpen their social skills such as sharing, taking turns, following instruction, and smiling. At the same time, a movement known as social inclusion attempts to increase valuable interactions between children with an intellectual disability and their non-disabled peers. Cognitive-behavioral treatments, a combination of the previous two treatment types, involves a strategical-metastrategical learning technique that teaches children math, language, and other basic skills pertaining to memory and learning. The first goal of the training is to teach the child to be a strategical thinker through making cognitive connections and plans. Then, the therapist teaches the child to be metastrategical by teaching them to discriminate among different tasks and determine which plan or strategy suits each task. Finally, family-oriented strategies delve into empowering the family with the skill set they need to support and encourage their child or children with an intellectual disability. In general, this includes teaching assertiveness skills or behavior management techniques as well as how to ask for help from neighbors, extended family, or day-care staff. As the child ages, parents are then taught how to approach topics such as housing/residential care, employment, and relationships. The ultimate goal for every intervention or technique is to give the child autonomy and a sense of independence using the acquired skills he/she has.

Although there is no specific medication for intellectual disability, many people with developmental disabilities have further medical complications and may be prescribed several medications. For example, autistic children with developmental delay may be prescribed antipsychotics or mood stabilizers to help with their behavior. Use of psychotropic medications such as benzodiazepines in people with intellectual disability requires monitoring and vigilance as side effects occur commonly and are often misdiagnosed as behavioral and psychiatric problems.

Excellent for single-focus disease. With multi-focal disease 60% have a chronic course, 30% achieve remission and mortality is up to 10%.

The main treatment for obesity consists of dieting and physical exercise. Diet programs may produce weight loss over the short term, but maintaining this weight loss is frequently difficult and often requires making exercise and a lower food energy diet a permanent part of a person's lifestyle.

In the short-term low carbohydrate diets appear better than low fat diets for weight loss. In the long term; however, all types of low-carbohydrate and low-fat diets appear equally beneficial. A 2014 review found that the heart disease and diabetes risks associated with different diets appear to be similar. Promotion of the Mediterranean diets among the obese may lower the risk of heart disease. Decreased intake of sweet drinks is also related to weight-loss. Success rates of long-term weight loss maintenance with lifestyle changes are low, ranging from 2–20%. Dietary and lifestyle changes are effective in limiting excessive weight gain in pregnancy and improve outcomes for both the mother and the child. Intensive behavioral counseling is recommended in those who are both obese and have other risk factors for heart disease.

Five medications have evidence for long-term use orlistat, lorcaserin, liraglutide, phentermine–topiramate, and naltrexone–bupropion. They result in weight loss after one year ranged from 3.0 to 6.7 kg over placebo. Orlistat, liraglutide, and naltrexone–bupropion are available in both the United States and Europe, whereas lorcaserin and phentermine–topiramate are available only in the United States. European regulatory authorities rejected the latter two drugs in part because of associations of heart valve problems with lorcaserin and more general heart and blood vessel problems with phentermine–topiramate. Orlistat use is associated with high rates of gastrointestinal side effects and concerns have been raised about negative effects on the kidneys. There is no information on how these drugs affect longer-term complications of obesity such as cardiovascular disease or death.

The most effective treatment for obesity is bariatric surgery. The types of procedures include laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, vertical-sleeve gastrectomy, and biliopancreatic diversion. Surgery for severe obesity is associated with long-term weight loss, improvement in obesity related conditions, and decreased overall mortality. One study found a weight loss of between 14% and 25% (depending on the type of procedure performed) at 10 years, and a 29% reduction in all cause mortality when compared to standard weight loss measures. Complications occur in about 17% of cases and reoperation is needed in 7% of cases. Due to its cost and risks, researchers are searching for other effective yet less invasive treatments including devices that occupy space in the stomach.

Usher syndrome, also known as Hallgren syndrome, Usher-Hallgren syndrome, retinitis pigmentosa-dysacusis syndrome, or dystrophia retinae dysacusis syndrome, is an extremely rare genetic disorder caused by a mutation in any one of at least 11 genes resulting in a combination of hearing loss and visual impairment. It is a leading cause of deafblindness and is at present incurable.

Usher syndrome is classed into three subtypes according to onset and severity of symptoms. All three subtypes are caused by mutations in genes involved in the function of the inner ear and retina. These mutations are inherited in an autosomal recessive pattern.

In medicine, Infantilism is an obsolete term for various, often unrelated disorders of human development, up to developmental disability, which consist of retention of the physical and/or psychological characteristics of early developmental stages (infant, child) into a relatively advanced age.

Various types of infantilism were recognized, lumped together in the above superficial description. With better understanding of the endocrine system and genetic disorders, various disorders which included the word "infantilism" received other names. For example, Brissaud's infantilism, described by Édouard Brissaud in 1907 is now known as myxedema (a form of hypothyroidism); "intestinal infantilism" of Christian Archibald Herter is called coeliac disease. The Turner syndrome was described as "a syndrome of infantilism" by Henry Turner himself.

Terms such as "genital infantilism" (infantilism in development of genitals, hypogenitalism), or "sexual infantilism" (lack of sexual development after expected puberty or delayed puberty) may still be seen, and are considered to be synonyms of hypogonadism. "Somatic infantilism" refers to infantilism of overall bodily development. Speech infantilism is a speech disorder.

Similarly to some other medical terms (cretinism, idiotism), "infantilism"/"infantile" may be used pejoratively (synonymous to "immature").

Sinding-Larsen and Johansson syndrome, named after Swedish surgeon Sven Christian Johansson (1880-1959), and Christian Magnus Falsen Sinding-Larsen (1866-1930), a Norwegian physician, is an analogous condition to Osgood–Schlatter disease involving the patellar tendon and the lower margin of the patella bone, instead of the upper margin of the tibia, as is the case in Osgood-Schlatter. This variant was discovered in 1908, during a winter indoor Olympic qualifier event in Scandinavia. Sever's disease is a similar condition affecting the heel.

This condition called Sinding-Larsen and Johansson syndrome was described independently by Sinding-Larsen in 1921 and Johansson in 1922.

People with Laron syndrome have strikingly low rates of cancer and diabetes, although they appear to be at increased risk of accidental death due to their stature.