Kleefstra syndrome affects males and females equally and approximately, 75% of all documented cases are caused by Eu-HMTase1 disruptions while only 25% are caused by 9q34.3 deletions. There are no statistics on the effect the disease has on life expectancy due to the lack of information available.

Due to its recent discovery, there are currently no existing treatments for Kleefstra syndrome.

Treatments for ATR-16 syndrome depend on the symptoms experienced by any individual. Alpha thalassemia is usually self-limiting, but in some cases may require a blood transfusion or chelating treatment.

While no genetic syndrome is capable of being cured, treatments are available for some symptoms. External fixators have been used for limbic and facial reconstructions.

While only a few adults have been reported with 2q37 microdeletion syndrome, it is predicted that this number will rise as various research studies continue to demonstrate that most with the disorder do not have a shortened life span.

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 of cause: Due to the genetic cause, no treatment of the cause is possible.

Treatment of manifestations: routine treatment of ophthalmologic, cardiac, and neurologic findings; speech, occupational, and physical therapies as appropriate; specialized learning programs to meet individual needs; antiepileptic drugs or antipsychotic medications as needed.

Surveillance: routine pediatric care; routine developmental assessments; monitoring of specific identified medical issues.

The incidence rate of ATR-16 syndrome is not easy to estimate and it is thought to be underdiagnosed. Scientists have described more than 20 cases as of 2013.

Most affected people have a stable clinical course but are often transfusion dependent.

Miller-Dieker occurs in less than one in 100000 people and can occur in all races.

MDS was named for the two physicians, James Q. Miller and H. Dieker., who independently described the condition in the 1960s. The hallmark of MDS is lissencephaly, a condition in which the outer layer of the brain, the cerebral cortex, is abnormally thick and lacks the normal convolutions (gyri). In some areas of the brain, gyri are fewer in number but wider than normal (pachygyri). Other areas lack gyri entirely (agyri). Normally, during the third and fourth months of pregnancy, the brain cells in the baby multiply and move to the surface of the brain to form the cortex. Lissencephaly is caused by a failure of this nerve cell migration. MDS is often called Miller-Dieker lissencephaly syndrome.

JQ Miller described the disease and in 1969 H Dieker emphasized that it should also take the name lissencephaly syndrome because several malformations occur beyond the brain itself. When MDS was initially described, geneticists assumed it followed an autosomal recessive pattern of inheritance. In the early 1990s, several patients with Miller–Dieker syndrome were found to be missing a small portion of chromosome 17. (17p13.3) (a partial deletion).

Therapy can help developmental delays, as well as physiotherapy for the low muscle tone. Exercise and healthy eating can reduce weight gain. Treatments are available for seizures, eczema, asthma, infections, and certain bodily ailments.

Two international research studies are currently underway. The International Genetic Study done with the Spinner Laboratory at The Children's Hospital of Philadelphia studies the ring 20 chromosome at the molecular level. The Clinical Research Study collects clinical information from parents to create a database of about the full spectrum of patients with ring chromosome 20 syndrome.

There is no cure for McLeod syndrome; the treatment is supportive depending on symptoms. Medication may assist with management of epilepsy, and cardiac and psychiatric features, although patients may respond poorly to treatment for chorea.

Limited data is available for the long-term prognosis of ring chromosome 20 syndrome since only over 60 patients with this syndrome have been reported in published literature. Optimal control of seizures appears to be the determining factor, but early diagnosis and a comprehensive management plan with multidisciplinary support is also thought be to be important.

There is no cure for this syndrome. Treatment is supportive and symptomatic. All children with Mowat–Wilson syndrome required early intervention with speech therapy, occupational therapy and physical therapy.

Treatments range from platelet transfusions to surgery aimed at either centralizing the hand over the ulna to improve functionality of the hand or aimed at 'normalizing' the appearance of the arm, which is much shorter and 'clubbed.' There is some controversy surrounding the role of surgery. The infant mortality rate has been curbed by new technology, including platelet transfusions, which can even be performed in utero. The critical period is the first and sometimes second year of life. For most people with TAR, platelet counts improve as they grow out of childhood.

The true prevalence of PMS has not been determined. More than 1200 people have been identified worldwide according the Phelan-McDermid Syndrome Foundation. However, it is believed to be underdiagnosed due to inadequate genetic testing and lack of specific clinical features. It is known to occur with equal frequency in males and females. Studies using chromosomal microarray for diagnosis indicate that at least 0.5% of cases of ASD can be explained by mutations or deletions in the "SHANK3" gene. In addition when ASD is associated with ID, "SHANK3" mutations or deletions have been found in up to 2% of individuals.

While there is no specific treatment for the underlying genetic cause of LFS; corrective procedures, preventive intervention measures and therapies may be considered in the treatment and management of the many craniofacial, orthopedic and psychiatric problems associated with the disorder. More pressing issues such as cardiac involvement or epileptic seizures should be routinely examined and monitored. Close attention and specialized follow-up care, including neuropshycological evaluation methods and therapies, and special education, should be given to diagnose and prevent psychiatric disorders and related behavioral problems such as psychosis and outbursts of aggression.

Research on the risk for developing schizophrenia in Ashkenazi Jews and other populations showed that 3q29 microdeletion syndrome leads to a significant higher rate of schizophrenia.

Treatment for Smith–Magenis syndrome relies on managing its symptoms. Children with SMS often require several forms of support, including physical therapy, occupational therapy and speech therapy. Support is often required throughout an affected person's lifetime.

Medication is often used to address some symptoms. Melatonin supplements and trazodone are commonly used to regulate sleep disturbances. In combination with exogenous melatonin, blockade of endogenous melatonin production during the day by the adrenergic antagonist acebutolol can increase concentration, improve sleep and sleep timing and aid in improvement of behaviour. Other medications (such as risperdal) are sometimes used to regulate violent behavior.

A typical patient with severe McLeod syndrome that begins in adulthood lives for an additional 5 to 10 years. Patients with cardiomyopathy have elevated risk for congestive heart failure and sudden cardiac death. The prognosis for a normal life span is often good in some patients with mild neurological or cardiac sequelae.

On several locations in the world people are studying on the subject of 1q21.1 deletion syndrome. The syndrome was identified for the first time with people with heart abnormalities. The syndrome has later been found with patients with autism and schizophrenia. Research is done on patients with a symptom of the syndrome, to find more patients with the syndrome.

There may be a relation between autism and schizophrenia. Literature shows that nine locations have been found on the DNA where the syndromes related to autism or schizophrenia can be found, the so-called "hotspots": 1q21.1, 3q29, 15q13.3, 16p11.2, 16p13.1, 16q21, 17p12, 21q11.2 and 21q13.3. With a number of hotspots both autism and schizophrenia were observed at that location. In other cases, either autism or schizophrenia has been seen.

Statistical research showed that schizophrenia is more common in combination with 1q21.1 deletion syndrome. On the other side, autism is significantly more common with 1q21.1 duplication syndrome. Further research confirmed that the odds on a relation between schizophrenia and deletions at 1q21.1, 3q29, 15q13.3, 22q11.21 en Neurexin 1 (NRXN1) and duplications at 16p11.2 are at 7.5% or higher.

Common variations in the BCL9 gene, which is in the distal area, confer risk of schizophrenia and may also be associated with bipolar disorder and major depressive disorder.

Research is done on 10–12 genes on 1q21.1 that produce DUF1220-locations. DUF1220 is an unknown protein, which is active in the neurons of the brain near the neocortex. Based on research on apes and other mammals, it is assumed that DUF1220 is related to cognitive development (man: 212 locations; chimpanzee: 37 locations; monkey: 30 locations; mouse: 1 location). It appears that the DUF1220-locations on 1q21.1 are in areas that are related to the size and the development of the brain. The aspect of the size and development of the brain is related to autism (macrocephaly) and schizophrenia (microcephaly). It has been proposed that a deletion or duplication of a gene that produces DUF1220-areas might cause growth and development disorders in the brain

Another relation between macrocephaly with duplications and microcephaly with deletions has been seen in research on the HYDIN Paralog or HYDIN2. This part of 1q21.1 is involved in the development of the brain. It is assumed to be a dosage-sensitive gene. When this gene is not available in the 1q21.1 area, it leads to microcephaly. HYDIN2 is a recent duplication (found only in humans) of the HYDIN gene found on 16q22.2.

Research on the genes CHD1L and PRKAB2 within lymphoblast cells lead to the conclusion that anomalies appear with the 1q21.1-deletionsyndrome:

- CHD1L is an enzyme which is involved in untangling the chromatides and the DNA repair system. With 1q21.1 deletion syndrome a disturbance occurs, which leads to increased DNA breaks. The role of CHD1L is similar to that of helicase with the Werner syndrome

- PRKAB2 is involved in maintaining the energy level of cells. With 1q21.1-deletion syndrome this function was attenuated.

GJA5 has been identified as the gene that is responsible for the phenotypes observed with congenital heart diseases on the 1q21.1 location. In case of a duplication of GJA5 tetralogy of Fallot is more common. In case of a deletion other congenital heart diseases than tetralogy of Fallot are more common.

The Chromosome 18 Registry & Research Society

The Chromosome 18 Registry & Research Society in Europe

Chromosome 18 Clinical Research Center, University of Texas Health Science Center at San Antonio

Unique

Chromosome Disorder Outreach

Paris-Trousseau syndrome (PTS) is an inherited disorder characterized by mild hemorrhagic tendency associated with 11q chromosome deletion. It manifests as a granular defect within an individual's platelets. It is characterized by thrombocytes with defects in α-granule components which affects the cell's surfeace area and, consequently, its abitlity to spread when necessary.

"FLI1" has been suggested as a candidate.