Aneuploidy is often fatal, but in this case there is "X-inactivation" where the effect of the additional gene dosage due to the presence of extra X chromosomes is greatly reduced.

Much like Down syndrome, the mental effects of 49,XXXXY syndrome vary. Impaired speech and behavioral problems are typical. Those with 49,XXXXY syndrome tend to exhibit infantile secondary sex characteristics with sterility in adulthood and have some skeletal anomalies. Skeletal anomalies include:

- Genu valgum

- Pes cavus

- Fifth finger clinodactyly

The effects also include:

- Cleft palate

- Club feet

- Respiratory conditions

- Short or/and broad neck

- Low birth weight

- Hyperextensible joints

- Short stature

- Narrow shoulders

- Coarse features in older age

- Hypertelorism

- Epicanthal folds

- Prognathism

- Gynecomastia (rare)

- Muscular hypotonia

- Hypoplastic genitalia

- Cryptorchidism

- Congenital heart defects

- A very round face in infancy

45,X/46,XY mosaicism, also known as X0/XY mosaicism and mixed gonadal dysgenesis, is a rare disorder of sex development in humans associated with sex chromosome aneuploidy and mosaicism of the Y chromosome. This is called a mosaic karyotype because, like tiles in mosaic floors or walls, there is more than one type of cell.

The clinical manifestations are highly variable, ranging from partial virilisation and ambiguous genitalia at birth, to patients with a completely male or female gonads. Most individuals with this karyotype have apparently normal male genitalia, and a minority with female genitalia, with a significant number of individuals showing genital abnormalities or intersex characteristics. A significantly higher than normal number of other developmental abnormalities are also found in individuals with X0/XY mosaicism. Psychomotor development is normal.

Although similar in some ways to true hermaphroditism, the conditions can be distinguished histologically and by karyotyping. The observable characteristics (phenotype) of this condition are highly variable, ranging from gonadal dysgenesis in males, to Turner-like females and phenotypically normal males. The phenotypical expression may be ambiguous, intersex, or male or female depending on the extent of the mosaicism. The most common presentation of 45,X/46,XY karyotype is phenotypically normal male, next being genital ambiguity.

There is a range of chromosomal anomalies within 45,X/46,XY where the variations are very complex, and the actual result in living individuals is often not a simple picture. Most patients with this karyotype are known to have abnormal gonadal histology and heights considerably below their genetic potential. High gonadotropin levels have been described in both male and female patients, as well as low levels of testosterone in male patients. Dosage loss of SHOX gene is commonly associated with short stature. Psychomotor development is normal.

As the gonads may not be symmetrical, the development of the Müllerian duct and Wolffian duct may be asymmetrical, too. Because of the presence of dysgenetic gonadal tissue and Y chromosome material, there is a high risk of the development of a gonadoblastoma.

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.

Serkal syndrome is an autosomal recessive disorder in XX humans. It is caused by loss of function in WNT4, a protein involved in sex development. The main outcome is female to male sex reversal.

Males with 48, XXXY can have average or tall stature, which becomes more prominent in adulthood. Facial dysmorphism is common in males with 48, XXXY and can include increased distance between the eyes (hypertelorism), skin folds of the upper eyelid (epicanthal folds), up-slanting opening between the eyelids (palpebral fissures) and hooded eyelids. Other physical features include the fifth finger or "pinky" to be bent inwards towards the fourth finger (clinodactyly), short nail beds, flat feet, double jointedness (hyperextensibility) and prominent elbows with cubitus varus where the arm rests closer to the body. Musculoskeletal features may include congentical elbow dislocation and the limited ability of the feet to roll inwards while walking and upon landing. Micropenis is another common symptom of this syndrome.

Individuals affected with XXXY are also prone to developing Taurodontism, which often presents early in life, and can be an early indicator of XXY syndrome. Those with this syndrome are also prone to hip dysplasia, and other joint abnormalities. An individual’s symptoms vary due to differing androgen deficiencies, and also with alter with age. Prepubescent boys with XXXY syndrome may not differ in physical appearance from a child without the syndrome. This is likely because androgen levels do not differ among pre-pubescent boys, but a difference does arise as puberty progresses. Those with XXXY syndrome may also experience feminine distribution of adipose tissue, and gynecomastia may also be present. Tall stature is more likely to appear in adolescence, when androgen levels begin to differ between those with XXXY syndrome and those that do not have it.

XYY syndrome is a genetic condition in which a male has an extra Y chromosome. Symptoms are usually few. They may include being taller than average, acne, and an increased risk of learning problems. The person is generally otherwise normal, including normal fertility.

The condition is generally not inherited from a person's parents but rather occurs as a result of a random event during sperm cell development. Diagnosis is by a chromosomal analysis. There are 47 chromosomes, instead of the usual 46, giving a 47,XYY karyotype.

Treatment may include speech therapy or extra help with schoolwork. Outcomes are generally good. Prevention is not possible. The condition occurs in about 1 in 1,000 male births. Many people with the condition are unaware that they have it. The condition was first described in 1961.

Those with XXXY syndrome can have testicular dysgenesis and hypergonadotrophic hypogonadism. Testicular dygenesis is a condition in which a male has incomplete or complete loss of spermatogenesis, so that the individual produces very low levels, or no sperm. This results in infertility of that individual. Hypergonadotrophic hypogonadism is a condition in which the function of the testes in males is reduced and can result in low levels of sex steroids produced like testosterone.

The acronym CHILD stands for the symptoms of the syndrome:

- CH = Congenital Hemidysplasia—One side of the body, most of the time the right side, is poorly developed. The right ribs, neck, vertebrae, etc. may be underdeveloped and the internal organs may be affected.

- I - Ichthyosiform Erythroderma—At birth or shortly after birth, there are red, inflamed patches (erythroderma), and flaky scales (ichthyosis) on the side of the body that is affected. Hair loss on the same side may also be possible.

- LD - limb defects—Fingers on the hand or toes on the foot of the affected side may be missing. An arm or leg may also be shortened or even missing.

49,XXXXY syndrome is an extremely rare aneuploidic sex chromosomal abnormality. It occurs in approximately 1 out of 85,000 to 100,000 males.

People with the 47,XYY karyotype have an increased growth velocity from early childhood, with an average final height approximately 7 cm (3") above expected final height. In Edinburgh, Scotland, eight 47,XYY boys born 1967–1972 and identified in a newborn screening programme had an average height of 188.1 cm (6'2") at age 18—their fathers' average height was 174.1 cm (5'8½"), their mothers' average height was 162.8 cm (5'4"). The increased gene dosage of three X/Y chromosome pseudoautosomal region (PAR1) SHOX genes has been postulated as a cause of the increased stature seen in all three sex chromosome trisomies: 47,XXX, 47,XXY, and 47,XYY.

Severe acne was noted in a very few early case reports, but dermatologists specializing in acne now doubt the existence of a relationship with 47,XYY.

Testosterone levels (prenatally) are normal in 47,XYY males. Most 47,XYY males have normal sexual development and have normal fertility.

As babies and children, XXY males may have weaker muscles and reduced strength. As they grow older, they tend to become taller than average. They may have less muscle control and coordination than other boys of their age.

During puberty, the physical traits of the syndrome become more evident; because these boys do not produce as much testosterone as other boys, they have a less muscular body, less facial and body hair, and broader hips. As teens, XXY males may develop breast tissue and also have weaker bones, and a lower energy level than other males.

By adulthood, XXY males look similar to males without the condition, although they are often taller. In adults, possible characteristics vary widely and include little to no sign of affectedness, a , youthful build and facial appearance, or a rounded body type with some degree of gynecomastia (increased breast tissue). Gynecomastia is present to some extent in about a third of affected individuals, a slightly higher percentage than in the XY population. About 10% of XXY males have gynecomastia noticeable enough that they may choose to have cosmetic surgery.

Affected males are often infertile, or may have reduced fertility. Advanced reproductive assistance is sometimes possible.

The term "hypogonadism" in XXY symptoms is often misinterpreted to mean "small testicles" when it means decreased testicular hormone/endocrine function. Because of this (primary) hypogonadism, individuals will often have a low serum testosterone level but high serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. Despite this misunderstanding of the term, however, it is true that XXY men may also have microorchidism (i.e., small testicles).

The testicle size of affected males are usually less than 2 cm in length (and always shorter than 3.5 cm), 1 cm in width and 4 ml in volume.

XXY males are also more likely than other men to have certain health problems that typically affect females, such as autoimmune disorders, breast cancer, venous thromboembolic disease, and osteoporosis. In contrast to these potentially increased risks, it is currently thought that rare X-linked recessive conditions occur less frequently in XXY males than in normal XY males, since these conditions are transmitted by genes on the X chromosome, and people with two X chromosomes are typically only carriers rather than affected by these X-linked recessive conditions.

Isodicentric 15, also called idic(15), partial tetrasomy 15q, or inverted duplication 15 (inv dup 15), is a chromosome abnormality in which a child is born with extra genetic material from chromosome 15. People with idic(15) are typically born with 47 chromosomes in their body cells, instead of the normal 46. The extra chromosome is made up of a piece of chromosome 15 that has been duplicated end-to-end like a mirror image. It is the presence of this extra genetic material that is thought to account for the symptoms seen in some people with idic(15). Individuals with idic(15) have a total of four copies of this chromosome 15 region instead of the usual two copies (1 copy each on the maternal and paternal chromosomes).

The syndrome is also often referred to by the broader term "Chromosome 15q11.2-q13.1 Duplication Syndrome", shortened to Dup15q syndrome, a name that is supported and actively promoted by the US-based support organization Dup15q Alliance. Dup15q syndrome is a broader disease term, as it includes both idic(15) and interstitial 15q11.2-q13.1, another type of duplication that causes similar clinical traits.

The extra chromosome is occasionally found in the mosaic state, i.e. some of the cells carry the marker chromosome. However, mostly because of the marker's instability and tendency to be lost during cell division (mitosis), some cells are completely normal with 46 chromosomes. Occasionally, cells may have more than one idic(15), resulting in 48 or 49 chromosomes in all or some of their cells. A similar clinical picture albeit to a milder degree could be expected in individuals that have the extra chromosome 15 material as an interstitial duplication (when the extra piece of chromosome 15 is included "within" the long arm of one of the two copies of chromosome 15, rather than as a small extra 'marker' chromosome) - often abbreviated to int dup(15); the individual thus having 46 chromosomes.

About 10–15% of human couples are infertile, unable to conceive. In approximately in half of these cases, the underlying cause is related to the male. The underlying causative factors in the male infertility can be attributed to environmental toxins, systemic disorders such as, hypothalamic–pituitary disease, testicular cancers and germ-cell aplasia. Genetic factors including aneuploidies and single-gene mutations are also contributed to the male infertility. Patients suffering from nonobstructive azoospermia or oligozoospermia show microdeletions in the long arm of the Y chromosome and/or chromosomal abnormalities, each with the respective frequency of 9.7% and 13%. A large percentage of human male infertility is estimated to be caused by mutations in genes involved in primary or secondary spermatogenesis and sperm quality and function. Single-gene defects are the focus of most research carried out in this field.

NR5A1 mutations are associated with male infertility, suggesting the possibility that these mutations cause the infertility. However, it is possible that these mutations individually have no major effect and only contribute to the male infertility by collaboration with other contributors such as environmental factors and other genomics variants. Vice versa, existence of the other alleles could reduce the phenotypic effects of impaired NR5A1 proteins and attenuate the expression of abnormal phenotypes and manifest male infertility solely.

The effect of the disorder is female to male sex reversal. Patients also exhibit renal, adrenal, and lung dysgenesis. One indicator is low levels of unconjugated estriol in maternal serum, because this denotes adrenal hypoplasia.

The appearance of XX males can fall into one of three categories: 1) males that have normal internal and external genitalia, 2) males with external ambiguities, and 3) males that have both internal and external genital ambiguities (true hermaphrodites). External genital ambiguities can include hypospadias, micropenis, and clitoromegaly. On average, the appearance of XX males differs from that of an XY male in that they are smaller in height and weight. Most XX males have small testes, are sterile, and have an increase in maldescended testicles compared to XY males. Some XX male individuals have decreased amounts of body hair and decreased libido. Individuals with this condition sometimes have feminine characteristics, with varying degrees of gynecomastia but with no intra-abdominal Müllerian tissue. According to research at the University of Oklahoma health science centers, despite XX males exhibiting feminine characteristics, their behaviours are usually representative of masculinity in their culture.

XXYY syndrome is a sex chromosome anomaly in which males have an extra X and Y chromosome. Human cells usually contain two sex chromosomes, one from the mother and one from the father. Usually, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The appearance of at least one Y chromosome with a properly functioning SRY gene makes a male. Therefore, humans with XXYY are genotypically male. Males with XXYY syndrome have 48 chromosomes instead of the typical 46. This is why XXYY syndrome is sometimes written as 48,XXYY syndrome or 48,XXYY. It is estimated that XXYY affects one in every 18,000–40,000 male births.

This syndrome is inherited as an autosomal disease. It affects both males and females but the phenotype differs. In both sexes sensorineural deafness occurs but in females ovarian dysgenesis also occurs.

XX gonadal dysgenesis is a type of female hypogonadism in which no functional ovaries are present to induce puberty in an otherwise normal girl whose karyotype is found to be 46,XX. With nonfunctional "streak" ovaries she is low in estrogen levels (hypoestrogenic) and has high levels of FSH and LH. Estrogen and progesterone therapy is usually then commenced.

Congenital hemidysplasia with ichthyosiform erythroderma and limb defects (also known as "CHILD syndrome") is a genetic disorder with onset at birth seen almost exclusively in females. The disorder is related to CPDX2, and also has skin and skeletal abnormalities, distinguished by a sharp midline demarcation of the ichthyosis with minimal linear or segmental contralateral involvement.

The acronym was introduced in 1980.

While it is possible to characterise XXY males based on physical characteristics, substantial variation in physical and developmental traits mean the only reliable method of positive or negative identification is karyotype testing.

External genitalia are often ambiguous, the degree depending mainly on the amount of testosterone produced by the testicular tissue between 8 and 16 weeks of gestation.

True hermaphroditism, clinically known as ovotesticular disorder of sex development, is a medical term for an intersex condition in which an individual is born with ovarian and testicular tissue. More commonly one or both gonads is an ovotestis containing both types of tissue.

Although similar in some ways to mixed gonadal dysgenesis, the conditions can be distinguished histologically.

17-β-Hydroxysteroid dehydrogenase III deficiency is clinically characterized by either ambiguous external genitalia or complete female external genitalia at birth; as a consequence of impaired male sexual differentiation in 46,XY individuals, as well as:

- Hypothyroidism

- Cryptorchidism

- Infertility

- Abnormality of metabolism

XX male syndrome is a rare congenital condition where an individual with a female genotype has phenotypically male characteristics that can vary between cases. In 90% of these individuals the syndrome is caused by unequal crossing over between X and Y chromosomes during meiosis in the father, and results in the X chromosome containing the SRY gene, as opposed to the Y chromosome where it is normally found. When the X with the SRY gene combines with a normal X from the mother during fertilization, the result is an XX male. Less common are SRY-negative XX males which can be caused by a mutation in an autosomal or X chromosomal gene. The masculinization of XX males is variable.

This syndrome is diagnosed through various detection methods and occurs in approximately 1:20 000 newborn males, making it less common than Klinefelter syndrome. Treatment is medically unnecessary, although some individuals choose to undergo treatments to make them appear more male or female. It is also called de la Chapelle syndrome, for Albert de la Chapelle, who characterized it in 1972.

Distal trisomy 10 is a rare chromosomal disorder that causes several physical defects and intellectual disability.

Humans, like all sexually reproducing species, have somatic cells that are in diploid [2N] state, meaning that N represent the number of chromosomes, and 2 the number of their copies. In humans, there are 23 chromosomes, but there are two sets of them, one from mother and one from father, totaling in 46, that are arranged according to their size, function and genes they carry. Each cell is supposed to have two of each, but sometimes due to mutations or malfunctions during cell division, mistakes are made that cause serious health problems. One such error is the cause of Distal trisomy 10q disorder.

Each chromosome has two arms, labeled p (for petite, or short) and q (for long). If both arms are equal in length, the chromosome is said to be metacentric. If arms' lengths are unequal, chromosome is said to be submetacentric, and if p arm is so short that is hard to observe, but still present, then the chromosome is acrocentric. In Distal Trisomy 10q disorder, end or distal portion of the q (long) arm of the chromosome number 10 appears to be present three times, rather than two times as it is supposed to be. This extra arm results in chromosome 10 trisomy, meaning that three arms are present. Depending on the length of the aberrant arm, the severity can vary from case to case. Often the source of this chromosomal error is a translocation in one of the parents. Sometimes it occurs spontaneously, in which case it is termed "de novo".

This syndrome has a large range of outcomes depending on how much chromosomal material is involved. Outcomes include: very slow postnatal growth, hypotonia, lack of coordination skills and mild to severe cases of intellectual disability, digestive issues, and heart and kidney problems. Individuals with this disorder can also be distinguished by their facial features. Number of support groups do exist in the United States, where affected families can meet and discuss problems they encounter, possible treatments and can find emotional support.