There is no medical treatment for either syndrome but there are some recommendations that can help with prevention or early identification of some of the problems. Children with either syndrome should have their hearing tested, and adults should be aware that the hearing loss may not develop until the adult years. Yearly visits to an ophthalmologist or other eye care professional who has been informed of the diagnosis of Stickler or Marshall syndrome is important for all affected individuals. Children should have the opportunity to have myopia corrected as early as possible, and treatment for cataracts or detached retinas may be more effective with early identification. Support for the joints is especially important during sports, and some recommend that contact sports should be avoided by those who have very loose joints.

Treatment of Roberts syndrome is individualized and specifically aimed at improving the quality of life for those afflicted with the disorder. Some of the possible treatments include: surgery for the cleft lip and palate, correction of limb abnormalities (also through surgery), and improvement in prehensile hand grasp development.

Treatment of Aicardi syndrome primarily involves management of seizures and early/continuing intervention programs for developmental delays.

Additional comorbidities and complications sometimes seen with Aicardi syndrome include porencephalic cysts and hydrocephalus, and gastro-intestinal problems. Treatment for porencephalic cysts and/or hydrocephalus is often via a shunt or endoscopic of the cysts, though some require no treatment. Placement of a feeding tube, fundoplication, and surgeries to correct hernias or other gastrointestinal structural problems are sometimes used to treat gastro-intestinal issues.

Since the symptoms caused by this disease are present at birth, there is no “cure.” The best cure that scientists are researching is awareness and genetic testing to determine risk factors and increase knowledgeable family planning. Prevention is the only option at this point in time for a cure.

Treatment for the disease itself is nonexistent, but there are options for most of the symptoms. For example, one suffering from hearing loss would be given hearing aids, and those with Hirschsprung’s disorder can be treated with a colostomy.

At the 2005 American Society of Human Genetics meeting, Francis Collins gave a presentation about a treatment he devised for children affected by Progeria. He discussed how farnesyltransferase inhibitor (FTI) affects H-Ras. After his presentation, members of the Costello Syndrome Family Network discussed the possibility of FTIs helping children with Costello syndrome. Mark Kieran, who presented at the 1st International Costello Syndrome Research Symposium in 2007, agreed that FTIs might help children with Costello syndrome. He discussed with Costello advocates what he had learned in establishing and running the Progeria clinical trial with an FTI, to help them consider next steps.

Another medication that affects H-Ras is Lovastatin, which is planned as a treatment for neurofibromatosis type I. When this was reported in mainstream news, the Costello Syndrome Professional Advisory Board was asked about its use in Costello Syndrome. Research into the effects of Lovastatin was linked with Alcino Silva, who presented his findings at the 2007 symposium. Silva also believed that the medication he was studying could help children with Costello syndrome with cognition.

A third medication that might help children with Costello syndrome is a MEK inhibitor that helps inhibit the pathway closer to the cell nucleus.

Surgery is typically used to correct structural heart defects and syndactyly. Propanolol or beta-adrenergic blockers are often prescribed as well as insertion of a pacemaker to maintain proper heart rhythm. With the characterization of Timothy syndrome mutations indicating that they cause defects in calcium currents, it has been suggested that calcium channel blockers may be effective as a therapeutic agent.

Medical management of children with Trisomy 13 is planned on a case-by-case basis and depends on the individual circumstances of the patient. Treatment of Patau syndrome focuses on the particular physical problems with which each child is born. Many infants have difficulty surviving the first few days or weeks due to severe neurological problems or complex heart defects. Surgery may be necessary to repair heart defects or cleft lip and cleft palate. Physical, occupational, and speech therapy will help individuals with Patau syndrome reach their full developmental potential. Surviving children are described as happy and parents report that they enrich their lives. The cited study grouped Edwards syndrome, which is sometimes survivable beyond toddlerhood, along with Patau, hence the median age of 4 at the time of data collection.

Many professionals that are likely to be involved in the treatment of those with Stickler's syndrome, include anesthesiologists, oral and maxillofacial surgeons; craniofacial surgeons; ear, nose, and throat specialists, ophthalmologists, optometrists, audiologists, speech pathologists, physical therapists and rheumatologists.

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.

The outcome of this disease is dependent on the severity of the cardiac defects. Approximately 1 in 3 children with this diagnosis require shunting for the hydrocephaly that is often a consequence. Some children require extra assistance or therapy for delayed psychomotor and speech development, including hypotonia.

Because the variability of this disease is so great and the way that it reveals itself could be multi-faceted; once diagnosed, a multidisciplinary team is recommended to treat the disease and should include a craniofacial surgeon, ophthalmologist, pediatrician, pediatric urologist, cardiologist, pulmonologist, speech pathologist, and a medical geneticist. Several important steps must be followed, as well.

- Past medical history

- Physical examination with special attention to size and measurements of facial features, palate, heart, genitourinary system and lower respiratory system

- Eye evaluation

- Hypospadias assessment by urologist

- Laryngoscopy and chest x-ray for difficulties with breathing/swallowing

- Cleft lip/palate assessment by craniofacial surgeon

- Assessment of standard age developmental and intellectual abilities

- Anal position assessment

- Echocardiogram

- Cranial imaging

Many surgical repairs may be needed, as assessed by professionals. Furthermore, special education therapies and psychoemotional therapies may be required, as well. In some cases, antireflux drugs can be prescribed until risk of breathing and swallowing disorders are removed. Genetic counseling is highly advised to help explain who else in the family may be at risk for the disease and to help guide family planning decisions in the future.

Because of its wide variability in which defects will occur, there is no known mortality rate specifically for the disease. However, the leading cause of death for people with Opitz G/BBB syndrome is due to infant death caused by aspiration due to esophageal, pharyngeal or laryngeal defects.

Fortunately, to date there are no factors that can increase the expression of symptoms of this disease. All abnormalities and symptoms are present at birth.

If the Hirschsprung's disease is treated in time, ABCD sufferers live otherwise healthy lives. If it is not found soon enough, death often occurs in infancy. For those suffering hearing loss, it is generally regressive and the damage to hearing increases over time. Digestive problems from the colostomy and reattachment may exist, but most cases can be treated with laxatives. The only other debilitating symptom is hearing loss, which is usually degenerative and can only be treated with surgery or hearing aids.

There is no cure for Williams syndrome. Suggestions include avoidance of extra calcium and vitamin D, as well as treating high levels of blood calcium. Blood vessel narrowing can be a significant health problem, and is treated on an individual basis.

Physical therapy is helpful to patients with joint stiffness and low muscle tone. Developmental and speech therapy can also help children and increase the success of their social interactions. Other treatments are based on a patient's particular symptoms.

The American Academy of Pediatrics recommends annual cardiology evaluations for individuals with Williams syndrome. Other recommended assessments include: ophthalmologic evaluations, an examination for inguinal hernia, objective hearing assessment, blood pressure measurement, developmental and growth evaluation, orthopedic assessments on joints, muscle tone, and ongoing feeding and dietary assessments to manage constipation and urinary problems.

Behavioral treatments have been shown to be effective. In regards to social skills it may be effective to channel their nature by teaching basic skills. Some of these are the appropriate way to approach someone, how and when to socialize in settings such as school or the workplace, and warning of the signs and dangers of exploitation. For the fear that they demonstrate cognitive-behavioral approaches, such as therapy, are the recommended treatment. One of the things to be careful of with this approach is to make sure that the patients' charming nature does not mask any underlying feelings.

Perhaps the most effective treatment for those with Williams syndrome is music. Those with Williams syndrome have shown a relative strength in regards to music, albeit only in pitch and rhythm tasks. Not only do they show a strength in the field but also a particular fondness for it. It has been shown that music may help with the internal and external anxiety that these people are more likely to be afflicted with. Something of note is that the typical person processes music in the superior temporal and middle temporal gyri. Those with Williams syndrome have a reduced activation in these areas but an increase in the right amygdala and cerebellum.

People affected by Williams syndrome are supported by multiple organizations, including the Canadian Association for Williams Syndrome and the Williams Syndrome Registry.

As a chromosomal condition, there is no cure for Turner syndrome. However, much can be done to minimize the symptoms. For example:

- Growth hormone, either alone or with a low dose of androgen, will increase growth and probably final adult height. Growth hormone is approved by the U.S. Food and Drug Administration for treatment of Turner syndrome and is covered by many insurance plans. There is evidence that this is effective, even in toddlers.

- Estrogen replacement therapy such as the birth control pill, has been used since the condition was described in 1938 to promote development of secondary sexual characteristics. Estrogens are crucial for maintaining good bone integrity, cardiovascular health and tissue health. Women with Turner Syndrome who do not have spontaneous puberty and who are not treated with estrogen are at high risk for osteoporosis and heart conditions.

- Modern reproductive technologies have also been used to help women with Turner syndrome become pregnant if they desire. For example, a donor egg can be used to create an embryo, which is carried by the Turner syndrome woman.

- Uterine maturity is positively associated with years of estrogen use, history of spontaneous menarche, and negatively associated with the lack of current hormone replacement therapy.

In terms of treatment/management one should observe what signs or symptoms are present and therefore treat those as there is no other current guideline. The affected individual should be monitored for cancer of:

- Thyroid

- Breast

- Renal

Prognoses for 3C syndrome vary widely based on the specific constellation of symptoms seen in an individual. Typically, the gravity of the prognosis correlates with the severity of the cardiac abnormalities. For children with less severe cardiac abnormalities, the developmental prognosis depends on the cerebellar abnormalities that are present. Severe cerebellar hypoplasia is associated with growth and speech delays, as well as hypotonia and general growth deficiencies.

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.

Treatment for Romano–Ward syndrome can "deal with" the imbalance between the right and left sides of the sympathetic nervous system which may play a role in the cause of this syndrome. The imbalance can be temporarily abolished with a left stellate ganglion block, which shorten the QT interval. If this is successful, surgical ganglionectomy can be performed as a permanent treatment.Ventricular dysrhythmia may be managed by beta-adrenergic blockade (propranolol)

Harlequin syndrome is not debilitating so treatment is not normally necessary. In cases where the individual may feel socially embarrassed, contralateral sympathectomy may be considered, although compensatory flushing and sweating of other parts of the body may occur. In contralateral sympathectomy, the nerve bundles that cause the flushing in the face are interrupted. This procedure causes both sides of the face to no longer flush or sweat. Since symptoms of Harlequin syndrome do not typically impair a person’s daily life, this treatment is only recommended if a person is very uncomfortable with the flushing and sweating associated with the syndrome.

Spanish researchers reported the development of a Costello mouse, with the G12V mutation, in early 2008. Although the G12V mutation is rare among children with Costello syndrome, and the G12V mouse does not appear to develop tumors as expected, information about the mouse model's heart may be transferrable to humans.

Italian and Japanese researchers published their development of a Costello zebrafish in late 2008, also with the G12V mutation. The advent of animal models may accelerate identification of treatment options.

The prognosis varies widely from case to case, depending on the severity of the symptoms. However, almost all people reported with Aicardi syndrome to date have experienced developmental delay of a significant degree, typically resulting in mild to moderate to profound intellectual disability. The age range of the individuals reported with Aicardi syndrome is from birth to the mid 40s.

There is no cure for this syndrome.

There is no specific treatment or cure for individuals affected with this type of syndrome, though some of the abnormal physical features may be surgically correctable.

Café au lait spots can be removed with lasers. Results are variable as the spots are often not completely removed or can come back after treatment. Often, a test spot is treated first to help predict the likelihood of treatment success.

More than 80% of children with Patau syndrome die within the first year of life. Children with the mosaic variation are usually affected to a lesser extent. In a retrospective Canadian study of 174 children with trisomy 13, median survival time was 12.5 days. One and ten year survival was 19.8% and 12.9% respectively.