Pre-implantation genetic diagnosis (PGD or PIGD) is a technique used to identify genetically normal embryos and is useful for couples who have a family history of genetic disorders. This is an option for people choosing to procreate through IVF. PGD is considered difficult due to it being both time consuming and having success rates only comparable to routine IVF.

1. Clinical Genetics and Genetic Testing

Genetic testing is necessary to confirm the diagnosis of PMS. A prototypical terminal deletion of 22q13 can be uncovered by karyotype analysis, but many terminal and interstitial deletions are too small to detect with this method. Chromosomal microarray should be ordered in children with suspected developmental delays or ASD. Most cases will be identified by microarray; however, small variations in genes might be missed. The falling cost for whole exome sequencing may replace DNA microarray technology for candidate gene evaluation. Biological parents should be tested with fluorescence "in situ" hybridization (FISH) to rule out balanced translocations or inversions. Balanced translocation in a parent increases the risk for recurrence and heritability within families (figure 3).

Clinical genetic evaluations and dysmorphology exams should be done to evaluate growth, pubertal development, dysmorphic features (table 1) and screen for organ defects (table 2)

2. Cognitive and Behavioral Assessment

All patients should undergo comprehensive developmental, cognitive and behavioral assessments by clinicians with experience in developmental disorders. Cognitive evaluation should be tailored for individuals with significant language and developmental delays. All patients should be referred for specialized speech/language, occupational and physical therapy evaluations.

3. Neurological Management

Individuals with PMS should be followed by a pediatric neurologist regularly to monitor motor development, coordination and gait, as well as conditions that might be associated with hypotonia. Head circumference should be performed routinely up until 36 months. Given the high rate of seizure disorders (up to 41% of patients) reported in the literature in patients with PMS and its overall negative impact on development, an overnight video EEG should be considered early to rule out seizure activity. In addition, a baseline structural brain MRI should be considered to rule out the presence of structural abnormalities.

4. Nephrology

All patients should have a baseline renal and bladder ultrasonography and a voiding cystourethrogram should be considered to rule out structural and functional abnormalities. Renal abnormalities are reported in up to 38% of patients with PMS. Vesicouretral reflux, hydronephrosis, renal agenesis, dysplasic kidney, polycystic kidney and recurrent urinary tract infections have all been reported in patients with PMS.

5. Cardiology

Congenital heart defects (CHD) are reported in samples of children with PMS with varying frequency (up to 25%)(29,36). The most common CHD include tricuspid valve regurgitation, atrial septal defects and patent ductus arteriousus. Cardiac evaluation, including echocardiography and electrocardiogram, should be considered.

6. Gastroenterology

Gastrointestinal symptoms are common in individuals with PMS. Gastroesophageal reflux, constipation, diarrhea and cyclic vomiting are frequently described.

Table 3: Clinical Assessment Recommendations in Phelan McDermid Syndrome.

Blastomere biopsy is a technique in which blastomeres are removed from the zona pellucida. It is commonly used to detect aneuploidy. Genetic analysis is conducted once the procedure is complete. Additional studies are needed to assess the risk associated with the procedure.

Suspicion of a chromosome abnormality is typically raised due to the presence of developmental delays or birth defects. Diagnosis of ring 18 is usually made via a blood sample. A routine chromosome analysis, or karyotype, is usually used to make the initial diagnosis, although it may also be made by microarray analysis. Increasingly, microarray analysis is also being used to clarify breakpoints. Prenatal diagnosis is possible via amniocentesis or chorionic villus sampling.

Most individuals with this condition do not survive beyond childhood. Individuals with MDS usually die in infancy and therefore do not live to the age where they can reproduce and transmit MDS to their offspring.

Ring chromosome 14 syndrome is extremely rare, the true rate of occurrence is unknown (as it is "less than" 1 per 1,000,000), but there are at least 50 documented cases in the literature.

The brain is usually grossly abnormal in outline when someone is diagnosed with Miller–Dieker syndrome. Only a few shallow sulci and shallow Sylvian fissures are seen; this takes on an hourglass or figure-8 appearance on the axial imaging. The thickness and measurement for a person without MDS is 3–4 mm. With MDS, a person's cortex is measured at 12–20 mm.

Diagnosis is usually based on clinical findings, although fetal chromosome testing will show trisomy 13. While many of the physical findings are similar to Edwards syndrome there are a few unique traits, such as polydactyly. However, unlike Edwards syndrome and Down syndrome, the quad screen does not provide a reliable means of screening for this disorder. This is due to the variability of the results seen in fetuses with Patau.

Diagnosis is achieved by examining the structure of the chromosomes through karyotyping; while once born, one can do the following to ascertain a diagnosis of the condition:

- MRI

- EEG

The ring 20 abnormality may be limited to as few as 5% of cells, so a screen for chromosomal mosaicism is critical. Newer array technology will not detect the ring chromosome and the standard metaphase chromosome analysis has been recommended. A karyotype analysis examining at least 50 cells should be requested to properly detect mosaicism.

At present, treatment for ring 18 is symptomatic, meaning that the focus is on treating the signs and symptoms of the conditions as they arise. To ensure early diagnosis and treatment, it is suggested that people with ring 18 undergo routine screenings for thyroid, hearing, and vision problems.

Diagnosing Jacobsen Syndrome can be difficult in some cases because it is a rare chromosomal disorder. There are a variety of tests that can be carried out like karyotype, cardiac echocardiogram, a renal sonogram, a platelet count, blood count, a brain imaging study. Genetic testing can be carried out for diagnosis. In which chromosomes are stained to give a barcode like appearance and studied under the microscope which reveals the broken and deleted genes. It can also be diagnosed early in the prenatal stage if there are any abnormalities seen in the ultrasound. A simple assessment of the symptoms can be done to diagnose the Syndrome. A thorough physical examination could be carried out to assess the symptoms.

Genetic testing methods such as fluorescence in situ hybridization (FISH) and chromosomal microarray are available for diagnosing Dup15q syndrome and similar genetic disorders.

With the increase in genetic testing availability, more often duplications outside of the 15q11.2-13.1 region are being diagnosed. The global chromosome 15q11.2-13.1 duplication syndrome specific groups only provide medical information and research for chromosome 15q11.2-13.1 duplication syndrome and not the outlying 15q duplications.

13q deletion syndrome can only be definitively diagnosed by genetic analysis, which can be done prenatally or after birth. Increased nuchal translucency in a first-trimester ultrasound may indicate the presence of 13q deletion.

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.

The diagnosis of Angelman syndrome is based on:

- A history of delayed motor milestones and then later a delay in general development, especially of speech

- Unusual movements including fine tremors, jerky limb movements, hand flapping and a wide-based, stiff-legged gait.

- Characteristic facial appearance (but not in all cases).

- A history of epilepsy and an abnormal EEG tracing.

- A happy disposition with frequent laughter

- A deletion or inactivity on chromosome 15 by array comparative genomic hybridization (aCGH) or by BACs-on-Beads technology.

Diagnostic criteria for the disorder were initially established in 1995 in collaboration with the Angelman syndrome Foundation (US); these criteria underwent revision in 2005.

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.

Individuals with Dup15q syndrome are at high risk for epilepsy, autism, and intellectual disability. Motor impairments are very common in individuals with the disorder. Rates of epilepsy in children with isodicentric duplications are higher than in children with interstitial duplications. A majority of patients with either duplication type (isodicentric or interstitial) have a history of gastrointestinal problems.

A study at the University of California, Los Angeles (UCLA) of 13 children with Dup15q syndrome and 13 children with nonsyndromic ASD (i.e., autism not caused by a known genetic disorder) found that, compared to children with nonsyndromic autism, children with Dup15q had significantly lower autism severity as measured by the Autism Diagnostic Observation Schedule (ADOS) (all children in the study met diagnostic criteria for ASD). However, children with Dup15q syndrome had significantly greater motor impairment and impairment of daily living skills than children in the nonsyndromic ASD group. Within the Dup15q syndrome cohort, children with epilepsy had greater cognitive impairment.

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.

Though the prevalence of Angelman syndrome is not precisely known, there are some estimates. The best data available are from studies of school age children, ages 6–13 years, living in Sweden and from Denmark where the diagnosis of AS children in medical clinics was compared to an 8-year period of about 45,000 births. The Swedish study showed an AS prevalence of about 1/20,000 and the Danish study showed a minimum AS prevalence of about 1/10,000.

Although there is no cure for 13q deletion syndrome, symptoms can be managed, usually with the involvement of a neurologist, rehabilitation physician, occupational therapist, physiotherapist, psychotherapist, nutritionist, special education professional, and/or speech therapist. If the affected child's growth is particularly slow, growth hormone treatment can be used to augment growth. Plastic surgeries can repair cleft palates, and surgical repair or monitoring by a pediatric cardiologist can manage cardiac defects. Some skeletal, neurological, genitourinary, gastrointestinal, and ophthalmic abnormalities can be definitively treated with surgery. Endocrine abnormalities can often be managed medically. Special educators, speech and occupational therapists, and physiotherapists can help a child develop skills in and out of school.

Wolf–Hirschhorn syndrome is a microdeletion syndrome caused by a deletion within HSA band 4p16.3 of the short arm of chromosome 4, particularly in the region of and . About 87% of cases represent a "de novo" deletion, while about 13% are inherited from a parent with a chromosome translocation. In the cases of familial translocation, there is a 2 to 1 excess of maternal transmission. Of the "de novo" cases, 80% are paternally derived. Severity of symptoms and expressed phenotype differ based on the amount of genetic material deleted. The critical region for determining the phenotype is at 4p16.3 and can often be detected through genetic testing and fluorescence in situ hybridization (FISH). Genetic testing and genetic counseling is offered to affected families.

There has been no treatment discovered for Jacobsen Syndrome until now but the Symptoms can be treated. 56% of children with Jacobsen Syndrome have congenital heart problems to keep them in check a baseline evaluation can be made by a paediatric cardiologist by carrying out an electrocardiogram or echocardiogram. Any problems that are found can be treated then.

Almost all affected children are born with a bleeding disorder, monthly CBT may help ease the problem. Consecutively Platelet transfusion and ddAVP can be carried out. Medication that interferes with platelet count should be avoided and oral contraceptive therapy may be considered for women with heavy bleeding during menses.

Children affected with Jacobsen Syndrome have severe to Moderate intellectual disabilities and cognitive impairment. An evaluation by a neuropsychologist or a behaviour specialist like a Psychiatrist or Psychologist can be performed, including brain imaging like MRI or ERP. Then as deemed appropriate intervention programs can be carried through. Music therapy is very beneficial for language development. According to the age, befitting vision and hearing test can aid in fixing problems related cognition. For problems related to behaviour like ADHD, medication or therapy would be required but a combination of both is more effective. An ophthalmologist should be consulted to treat the eye defects. Play and interactive games encourage the child to speak. Habilitiation in children should begin at an early age. A habilitation team includes professionals with special expertise in how disability affects everyday life, health and development. The entire family is supported to help the affected children and their families adjust better.

Wolf–Hirschhorn syndrome (WHS), also known as chromosome deletion Dillan 4p syndrome, Pitt–Rogers–Danks syndrome (PRDS) or Pitt syndrome, was first described in 1961 by Americans Herbert L. Cooper and Kurt Hirschhorn and, thereafter, gained worldwide attention by publications by the German Ulrich Wolf, and Hirschhorn and their co-workers, specifically their articles in the German scientific magazine "Humangenetik". It is a characteristic phenotype resulting from a partial deletion of chromosomal material of the short arm of chromosome 4 (del(4p16.3)).

Trisomy 22 is a chromosomal disorder in which there are three copies of chromosome 22 rather than two. It is a frequent cause of spontaneous abortion during the first trimester of pregnancy. Progression to the second trimester and live birth are rare. This disorder is found in individuals with an extra copy or a variation of chromosome 22 in some or all cells of their body. There are many kinds of disorders associated with Trisomy 22:

Emanuel Syndrome is named after the genetic contributions made by researcher Dr. Beverly Emanuel. This condition is assigned to individuals born with an unbalanced 11/22 translocation. That is, a fragment of chromosome 11 is moved, or translocated, to chromosome 22.

22q11 Deletion Syndrome is a rare condition which occurs in approximately 1 in 4000 births. This condition is identified when a band in the q11.2 section of the arm of chromosome 22 is missing or deleted. This condition has several different names: 22q11.2 Deletion Syndrome, Velocardiofacial syndrome, DiGeorge Syndrome, Conotruncal Anomaly Face syndrome, Opitz G/BBB Syndrome, and Cayler Cardiofacial Syndrome. The effects of this disorder are different in each individual but similarities exist such as heart defects, immune system problems, a distinctive facial appearance, learning challenges, cleft palate, hearing loss, kidney problems, hypocalcemia, and sometimes psychiatric issues.

22q11 microduplication syndrome is the opposite of the 22q11 deletion syndrome: in this condition, a band of q.11.2 section of chromosome 22 is duplicated. Individuals carrying this deficiency are relatively “normal” as in they don’t possess any major birth defects or major medical illnesses. This microduplication is more common than the deletion; this might be due to the milder phenotype of the individuals.

Phelan-McDermid Syndrome / 22q13 Deletion Syndrome is a condition caused by the deletion of the tip of the q arm on chromosome 22. Most individuals with this disorder experience cognitive delays; low muscle tone; and sleeping, eating, and behavioural issues.

Chromosome Ring 22 is a rare disorder caused by the break and re-join of both ends of chromosome 22, forming a ring. The effects on the individual with this disorder are dependent on the amount of genetic information lost during the break/re-join. Major characteristics for this disorder are intellectual disability, muscle weakness and lack of coordination.

Cat Eye Syndrome / Schmid Fraccaro Syndrome is a condition caused by a partial trisomy or tetrasomy in chromosome 22. A small extra chromosome is found, made up of the top half of chromosome 22 and a portion of the q arm at the q11.2 break. This chromosome can be found three or four times. This syndrome is referred as “Cat Eye” due to the eye appearance of reported affected individuals who have coloboma of the iris; however, this feature is only seen in about half of the cases.

Mosaic trisomy 22 is a disorder in which an extra chromosome 22 is found only in some cells of the body. The severity of each case is determined by the number of cells with this extra copy. Some characteristics of individuals with this condition are cardiac abnormalities, growth retardation, mental delay, etc.

Complete Trisomy 22 is in contrast with Mosaic trisomy 22; this disorder is characterized by an extra copy of chromosome 22 which is found in each cell of the body of the affected individual. These cases are very rare, and most of the affected individuals die before birth or shortly after.