XXXXX syndrome is the presence of three additional X chromosome

X chromosome

The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...

s. Diagnosis is done by karyotyping. Approximately 25 females have been described in medical literature worldwide with this extremely rare condition. The condition was first described in 1963. XXXXX syndrome is a type of aneuploidy

Aneuploidy

Aneuploidy is an abnormal number of chromosomes, and is a type of chromosome abnormality. An extra or missing chromosome is a common cause of genetic disorders . Some cancer cells also have abnormal numbers of chromosomes. Aneuploidy occurs during cell division when the chromosomes do not separate...

 (an abnormal number of chromosomes).

Physical traits

XXXXX syndrome is associated with microcephaly

Microcephaly

Microcephaly is a neurodevelopmental disorder in which the circumference of the head is more than two standard deviations smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life...

 (undersized skull), micrognathia (undersized jaw), and round face. The ears are generally low-set and malformed. Eyes are upslanting and show palpebral fissures, hypertelorism

Hypertelorism

Hypertelorism is an abnormally increased distance between two organs or bodily parts, usually referring to an increased distance between the orbits . In this condition the distance between the inner eye corners as well as the distance between the pupils is greater than normal...

, and strabismus

Strabismus

Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...

. Usually the nose is shaped with a broad and depressed nasal bridge and epicanthus, with the mouth having a cleft and highly arched palate, dental abnormalities, and thick, furrowed, and everted lips. The neck is webbed

Webbed neck

A webbed neck, or pterygium colli deformity, is a congenital skin fold that runs along the sides of the neck down to the shoulders.There are many variants.-Associated conditions:...

, much like the neck of a woman with Turner's syndrome.
The hands and feet are small with overlapping toes, camptodactyly

Camptodactyly

Camptodactyly is a medical condition involving fixed flexion deformity of the interphalangeal joints of the little finger. This involves permanent flexure of one or more phalanges...

, clinodactyly

Clinodactyly

-References:...

, talipes equinovarus, and metatarsus varus. Scoliosis

Scoliosis

Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...

 generally affects the spine and hypotonia

Hypotonia

Hypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...

 affects the muscles.

Internal organs

The heart is usually affected by patent ductus arteriosus

Patent ductus arteriosus

Patent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain...

, atrial septal defect

Atrial septal defect

Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...

, ventricular septal defect

Ventricular septal defect

A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...

, and aortic dextroposition. There is abnormal lobulation

Lobulation

A lobulation is an appearance resembling lobules.For instance, a the thyroid gland may become large and lobulated in Hashimoto's thyroiditis....

 of the lungs and neonatal asphyxia

Asphyxia

Asphyxia or asphyxiation is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs...

. The ovaries are abnormally shaped with a small uterus and kidney hypoplasia

Hypoplasia

Hypoplasia is underdevelopment or incomplete development of a tissue or organ. Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells. Hypoplasia is similar to aplasia, but less severe. It is technically not the opposite of hyperplasia...

.

Growth and development

XXXXX syndrome causes mental, growth, and motor retardation. There is occasional delayed puberty.
Behavior and performance is affected by opisthotonoid posture. Recent observations have indicated an average of a 10 to 15 IQ point decrease for each extra X chromosome. Thus, the average IQ of XXXXX individuals tends to be between 55 and 70.

External links

• Tetrasomy & Pentasomy X Syndrome Information and Support