Triplo X Syndrome

Triple X syndrome is a chromosomal variation characterized by the presence of an extra X chromosome in each cell of a human female. The condition is also known as triplo-X, trisomy X, XXX syndrome, 47,XXX aneuploidy, and super female syndrome. Triple X results during division of a parent's reproductive cells. Females with triple X are typically tall and slender with slightly higher sensitivity levels, and are not at any increased risk for medical problems. more...

Symptoms

Due to the lyonization, inactivation and formation of a Barr body in all female cells, only one X chromosome is active at any time in a female cell. Thus, triple X syndrome most often causes no unusual physical features or medical problems. Females with the condition are usually taller than average, may have menstrual irregularities, and, although rarely exhibiting severe mental impairments, sometimes have an increased risk of learning disabilities and delayed speech and language skills.

Triple X females tend to be gifted in areas involving creativity, intuitive sense, and empathy. Elevated levels of estrogen may play a role in enhancing sensitivity and youthful appearance. The taller height centered in the limbs, which results from growth plates remaining open longer during adolescence, is generally considered an aesthetic compliment.

Although body types and characteristics are distinguishable in triple X, the condition is verified only by karyotype testing. Mothers of triple X girls may identify with and bear traits of the condition without having the additional X chromosone. Other characteristic variants within the condition include showing little to no affectedness or having enhanced self-sufficient traits, the latter possibly linked to increased progesterone levels.

Most women with triple X have normal sexual development and are able to conceive children. A few may experience early onset of menstruation, due possibly to increases in both estrogen and progesterone, which work together in female sexual development.

A vast majority of the females with triple X have never been diagnosed. The usual diagnosis results from pre-natal testing methods, such as amniocentesis. Most medical professionals do not regard Triple X syndrome a disability, however disability status can be sought by parents for early intervention treatment when mild delay is present.

Cause

Triple X syndrome is not inherited, but usually occurs as a random event during the formation of reproductive cells (ovum and sperm). A change in cell division called nondisjunction can result in reproductive cells with additional chromosomes. For example, an oocyte or sperm cell may gain an extra copy of the X chromosome as a result of the nondisjunction. If one of these cells contributes to the genetic makeup of a child, the child will have an extra X chromosome in each of his or her cells. In some cases, trisomy X occurs during cell division in early fetal development.

Some females with triple X syndrome have an extra X chromosome in only some of their cells. These cases are called 46,XX/47,XXX mosaics.

Incidence

Triple X syndrome occurs in about 1 in 1,000 newborn girls. Five to ten girls with triple X syndrome are born in the United States each day.

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