The symptoms and prognosis of tetrasomy 9p are highly variable. The severity of the symptoms is largely determined by the size of the isochromosome, the specific regions of chromosome 9p that are duplicated, as well as the number and type of tissues that are affected in the mosaic form.

Most patients exhibit some degree of intellectual disability, abnormal skeletal and muscular development, and abnormal facial structures. Cognitive symptoms range from slight learning disabilities to severe deficits in intellectual functioning. Due to abnormal development of the muscles, individuals often experience limited or delayed mobility. Atypical facial features are characteristic of the syndrome, including widely spaced eyes, a large nose, and unusually positioned ears. Additionally, patients often have extra skin around the neck and widely spaced nipples. A wide range of renal, digestive, cardiac, respiratory, and nervous system abnormalities have been observed.

Though rare, a few cases of phenotypically normal individuals with tetrasomy 9p have been documented.

The most frequent reported symptoms in patients with duplication of 22q11.2 duplication syndrome are mental retardation/learning disabilility (97% of patients), delayed psychomotor development (67% of patients), growth retardation (63% of patients) and muscular hypotonia (43% of patients). However, these are common and relatively non-specific indications for cytogenetic analysis, and the extent to which the duplication of 22q11.2 causes these features is currently unknown. The duplication is frequently inherited from a normal parent, so it is clear that intellectual development can be normal.

Tetrasomy 9p (also known Tetrasomy 9p Syndrome) is a rare chromosomal disorder characterized by the presence of two extra copies of the short arm of chromosome 9 (called the p arm), in addition to the usual two. Symptoms of tetrasomy 9p vary widely among affected individuals, but typically include varying degrees of delayed growth, abnormal facial features, and intellectual disability. Symptoms of the disorder are comparable to those of trisomy 9p.

8p23.1 duplication syndrome is a rare genetic disorder caused by a duplication of a region from human chromosome 8. This duplication syndrome has an estimated prevalence of 1 in 64,000 births and is the reciprocal of the 8p23.1 deletion syndrome. The 8p23.1 duplication is associated with a variable phenotype including one or more of speech delay, developmental delay, mild dysmorphism, with prominent forehead and arched eyebrows, and congenital heart disease (CHD).

Recognised symptoms up till now are:

- Autism or autistic behaviors

- ADHD

- Learning disability

- Large head

- Dysmorphic facial appearance - mild

- Prominent forehead

- Wide-set eyes (hypertelorism)

- Schizophrenia

- Loose joints

- GERD

- Sleep disturbances

- Sleep Apnea

- Underdeveloped parts of brain - corpus callosum and cerebellar vermis

- Neuroblastoma

- Speech & developmental delays

- Chiari malformation of the brain

- Congenital heart defects

- Hypotonia

It is not clear whether the list of symptoms is complete. Very little information is known about the syndrome. The symptomology may be different among individuals, even in the same family.

22q11.2 duplication syndrome is a rare genetic disorder caused by a duplication of a segment at the end of chromosome 22.

Symptoms vary, but usually result in dysmorphisms in the skull, nervous system, and developmental delay. Dysmorphisms in the heart, kidneys, and musculoskeletal system may also occur. An infant with complete trisomy 9 surviving 20 days after birth showed clinical features including a small face, wide fontanelle, prominent occiput, micrognathia, low set ears, upslanting palpebral fissures, high-arched palate, short sternum, overlapping fingers, limited hip abduction, rocker bottom feet, heart murmurs and also a webbed neck.

Trisomy 9p is one of the most frequent autosomal anomalies compatible with long survival rate. A study of five cases showed an association with Coffin–Siris syndrome, as well as a wide gap between the first and second toes in all five, while three had brain malformations including dilated ventricles with hypogenesis of the corpus callosum and Dandy-Walker malformation.

1q21.1 duplication syndrome or 1q21.1 (recurrent) microduplication is a rare aberration of chromosome 1.

In a common situation a human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 duplication syndrome one chromosome of the pair is over complete, because a part of the sequence of the chromosome is duplicated twice or more. In 1q21.1, the '1' stands for chromosome 1, the 'q' stands for the long arm of the chromosome and '21.1' stands for the part of the long arm in which the duplication is situated.

Next to the duplication syndrome, there is also a 1q21.1 deletion syndrome. While there are two or three copies of a similar part of the DNA on a particular spot with the duplication syndrome, there is a part of the DNA missing with the deletion syndrome on the same spot. Literature refers to both the deletion and the duplication as the 1q21.1 copy-number variations (CNV).

The CNV leads to a very variable phenotype and the manifestations in individuals are quite variable. Some people who have the syndrome can function in a normal way, while others have symptoms of mental retardation and various physical anomalies.

Recognised symptoms are:

- Only one set of genes on the two chromosomes function (Haploinsufficiency)

- Thrombocytopenia-absent radius (TAR syndrome), in case of a class II-deletion

- Neurological-psychiatric problems: Autism; schizophrenia; epilepsy; learning problems; cognitive disabilities — mild to moderate; developmental delay — mild to moderate (milestones like sitting, standing and walking; come at a later period in childhood); children show an ataxic gait and fall down a lot

- Dysmorphism: Slightly unusual facial appearance; disturbed growth; skeletal malformations; small head (microcephaly); prominent forehead; bulbous nose; deep-set eyes; broad thumbs; broad toes; squint; very flexible joints; clavicular pseudoarthrosis (the collarbone doesn't develop normally) (Class II-deletion); An extra transverse crease of the fifth finger (Class II-deletion)); Problems with the development of the vagina (Müllerian aplasia)

- Eyes: Cataracts

- Heart abnormalities and cardiovascular anomalies (30% of the cases): Anomalous origin of the coronary artery (Class II-deletion)

- Kidneys: Missing kidney or floating kidneys

- Cancer: Neuroblastoma

- Sleep disturbances

It is not clear whether the list of symptoms is complete. Very little information is known about the syndrome. The syndrome can have completely different effects on members of the same family.

A common deletion is between 1.0–1.9Mb. Mefford states that the standard for a deletion is 1.35Mb. The largest deletion seen on a living human is over 5 Mb.

1q21.1 deletion syndrome or 1q21.1 (recurrent) microdeletion is a rare aberration of chromosome 1.

A human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 deletion syndrome, one chromosome of the pair is not complete, because a part of the sequence of the chromosome is missing. One chromosome has the normal length and the other is too short.

In 1q21.1, the '1' stands for chromosome 1, the 'q' stands for the long arm of the chromosome and '21.1' stands for the part of the long arm in which the deletion is situated.

The syndrome is a form of the 1q21.1 copy number variations and it is a deletion in the distal area of the 1q21.1 part. The CNV leads to a very variable phenotype and the manifestations in individuals are quite variable. Some people who have the syndrome can function in a normal way, while others have symptoms of mental retardation and various physical anomalies.

1q21.1 microdeletion is a very rare chromosomal condition. Only 46 individuals with this deletion have been reported in medical literature as of August 2011.

The phenotypic data on 11 patients indicated that cases are not always ascertained for CHD but that CHD was the most common single feature found in 6 out of 11 individuals. Developmental delay and/or learning difficulties were found in 5 out of 11 cases, but one prenatal case was developing normally at 15 months of age (Case 1,). Three other prenatal cases could not yet be reliably assessed. A variable degree of facial dysmorphism was present in 5 out of 11 individuals. Partial toe syndactyly has been found in one mother and son diad and adrenal anomalies in two probands but not in the duplicated mother of one of them. The phenotype is compatible with independent adult life with varying degrees of support.

Duplication of the GATA4 transcription factor () is believed to underlie the congenital heart disease and other genes, common to the duplication and deletion syndromes, can be regarded as candidates for the 8p23.1 duplication syndrome. These include the SOX7 transcription factor () for both CHD and developmental delay and the TNKS gene () for behavioural difficulties. The diaphragmatic hernia found in the 8p23.1 deletion syndrome has not been found in the 8p23.1 duplication syndrome to date.

The duplication may be associated with copy number changes of the adjacent olfactory receptor/defensin repeats (ORDRs) that predispose to the 8p23.1 deletion and duplication syndromes. High total copy numbers of these repeats have been associated with predisposition to psoriasis and low copy number with predisposition to Crohn's disease.

Full trisomy 9 is a lethal chromosomal disorder caused by having three copies (trisomy) of chromosome number 9. It can be a viable condition if trisomy affects only part of the cells of the body (mosaicism) or in cases of partial trisomy (trisomy 9p) in which cells have a normal set of two entire chromosomes 9 plus part of a third copy, usually of the short arm of the chromosome (arm p).

The severity of symptoms of idic(15) vary greatly between individuals. Individuals with idic(15) usually have delays in language development and motor skills such as walking or sitting up. Other traits may include low muscle tone (hypotonia), seizures (>50%), short stature, and intellectual disability. Distinctive facial features associated with idic(15), where present, are usually very subtle but may include epicanthal folds (skin folds at the inner corners of one or both eyes), broad forehead, a flattened nasal bridge, button nose, and a high arched palate (roof of the mouth). Many individuals with idic(15) display features of autism, such as problems with communication and social interactions, obsessional interests (often with interactive mechanisms like wheels, doors or switches), unpredictable sleep cycles (and a reduced need for sleep), and repetitive and stereotyped behaviors (e.g., lining up toys, playing with a toy in the same manner over and over again, hand flapping, rocking back and forth). A high pain threshold is often observed. If speech develops, it is often echolalic but some individuals do grasp some language. With a severely affected person there may be an inability to walk or talk.

There are two types of SGBS, each found on a different gene:

SGBS is also considered to be an overgrowth syndrome (OGS). OGS is characterized by a 2-3 standard deviation increase in weight, height, or head circumference above the average for sex and age. One of the most noted features of OGS is the increased risk of neoplasms in certain OGSs. SGBS in particular has been found to have a 10% tumor predisposition frequency with 94% of cases occurring in the abdominal region, most being malignant. It is common for tumors to be embryonal in type and appear before the age of 10.

There are five different types of tumors that patients with SGBS might develop, all intra-abdominal: Wilms tumor, Hepatoblastoma, Hepatocarcinoma, Gonadoblastoma, and Neuroblastoma.

The most common types of tumors developed in patients are the Wilms tumor and hepatoblastoma.

Hay–Wells syndrome (also known as AEC syndrome; see "Naming") is one of at least 150 known types of ectodermal dysplasia.These disorders affect tissues that arise from the ectodermal germ layer, such as skin, hair, and nails.

Chromosome 15q trisomy is an extremely rare genetic disorder, caused by a chromosomal aberration in which there is an excess copy of the long ("q") arm of human chromosome 15. The disorder is also known as Distal Duplication 15q and Partial Duplication 15q Syndrome.

The disorder is primarily characterized by growth abnormalities, which range from growth retardation to accelerated growth, intellectual disability, and distinctive malformations of the head and face. Additional abnormalities may involve malformation of the skeleton, spine and neck; fingers and/or toes; genitals (particularly in males); and, in some cases, heart problems. When accelerated growth is present, it is thought to result from the duplication of the IGF1 receptor gene.

People with the combination of Duane anomaly and radial ray malformations may have a variety of other signs and symptoms. These features include:

- Unusually shaped ears

- Hearing loss

- Heart and kidney defects

- A distinctive facial appearance

- An inward- and downward-turning foot (a clubfoot)

- Fused vertebrae.

Young–Madders syndrome is detectable from the fetal stage of development largely due to the distinctive consequences of holoprosencephaly, a spectrum of defects or malformations of the brain and face. Facial defects which may manifest in the eyes, nose, and upper lip, featuring cyclopia, anosmia, or in the growth of only a single central incisor, and severe overlapping of the bones of the skull. Cardiac and in some cases pulmonary deformities are present. Another signature deformity is bilateral polydactyly, and many patients also suffer from hypoplasia and genital deformities.

A contiguous gene syndrome (CGS), also known as a contiguous gene deletion syndrome is a clinical phenotype caused by a chromosomal abnormality, such as a deletion or duplication that removes several genes lying in close proximity to one another on the chromosome. The combined phenotype of the patient is a combination of what is seen when any individual has disease-causing mutations in any of the individual genes involved in the deletion. While it can be caused by deleted material on a chromosome, it is not, strictly speaking, the same entity as a segmental aneuploidy syndrome. A segmental aneuploidy syndrome is a subtype of CGS that regularly recur, usually due to non-allelic homologous recombination between low copy repeats in the region. Most CGS involve the X chromosome and affect male individuals.

One of the earliest and most famous examples of a CGS involves a male patient with Duchenne muscular dystrophy (DMD), chronic granulomatous disease (CGD), retinitis pigmentosa and intellectual disability. When it was discovered that an X chromosome deletion (specifically Xp21) was the underlying cause of all of these features, researchers were able to use this information to clone the genes responsible for DMD and CGD.

One of those more common CGS involves a deletion on the X chromosome (near Xp21) that encompasses "DMD" (causing Duchenne muscular dystrophy), "NROB1" (causing X-linked adrenal hypoplasia congenita) and "GK" (causing glycerol kinase deficiency). These patients will have all the common features of each individual disease, resulting in a very complex phenotype. Deletions near the distal tip of the p arm of the X chromosome are also a frequent cause of CGS. In addition to the previously described CGS that occur on the X chromosome, two other common syndromes are Langer-Giedion syndrome (caused by deletions of "TRPS1" and "EXT1" on 8q24 and WAGR syndrome (caused by deletions on 11q13 encompassing "PAX6" and "WT1".)

Potocki–Lupski syndrome (PTLS), also known as dup(17)p11.2p11.2 syndrome, trisomy 17p11.2 or duplication 17p11.2 syndrome, is a contiguous gene syndrome involving the microduplication of band 11.2 on the short arm of human chromosome 17 (17p11.2). The duplication was first described as a case study in 1996. In 2000, the first study of the disease was released, and in 2007, enough patients had been gathered to complete a comprehensive study and give it a detailed clinical description. PTLS is named for two researchers involved in the latter phases, Drs. Lorraine Potocki and James R. Lupski of Baylor College of Medicine.

PTLS was the first predicted of a homologous recombination (microdeletion or microduplication) where both reciprocal recombinations result in a contiguous gene syndrome. Its reciprocal disease is Smith–Magenis syndrome (SMS), in which the chromosome portion duplicated in PTLS is deleted altogether.

Potocki–Lupski syndrome is considered a rare disease, predicted to appear in at least 1 in 20,000 humans.

Symptoms of the syndrome include intellectual disability, autism, and other disorders unrelated to the listed symptoms.

The symptoms associated with this syndrome are variable, but common features include: low birthweight, low muscle tone at birth, poor feeding in infancy (often requiring feeding by tube for a period) and oromotor dyspraxia together with moderate developmental delays and learning disabilities but amiable behaviour. Other clinically important features include epilepsy, heart defects (atrial septal defect, ventricular septal defect) and kidney/urological anomalies. Silvery depigmentation of strands of hair have been noted in several patients. With age there is an apparent coarsening of facial features. 17q21.3 was reported simultaneously in 2006 by three independent groups, with each group reporting several patients, and is now recognised to be one of the more common recurrent microdeletion syndromes. Recently a patient with a small duplication in same segment of DNA has been described. An overview of the clinical features of the syndrome, by reviewing 22 individuals with a 17q21.31 microdeletion, estimated the disorder is present in one in every 16,000 people.

17q21.31 microdeletion syndrome (Koolen De Vries syndrome) is a rare genetic disorder caused by a deletion of a segment of chromosome 17 which contains six genes. This deletion syndrome was discovered independently in 2006 by three different research groups.

Monosomy 9p (also known as Alfi's Syndrome or simply 9P-) is a rare chromosomal disorder in which there is deletion (monosomy) of a portion of chromosome 9. Symptoms include microgenitalia, mental retardation with microcephaly and dysmorphic features.

The location has recently been narrowed to 9p22.2-p23.

Various clinical features have been associated with this disease including trigonocephaly, flattened occiput, prominent forehead, broad flat nasal bridge, anteverted nares, malformed external ears, hypertelorism, and hypertonia.

Many of the physical features associated with the disorder are congenital. Characteristic craniofacial abnormalities typically include a long, narrow head that is disproportionate to the body size, a broad and prominent forehead, and a triangular-shaped face with a hypoplastic midface, pointed chin, prominent mouth, fleshy tipped upturned nose, large ears, and full lips. The teeth may be abnormally crowded together in some affected individuals.

This is characterized by hand and arm abnormalities. The following are specific characteristics:

- Malformed or absent (aplasia) thumb

- A thumb that looks more like a finger

- Partial or complete absence of a radius

- Shortening and radial deviation of the forearms

- Triphalangeal thumb

- Duplication of the thumb (preaxial polydactyly)