Extra chromosome disorder refers to the genetic disorders found in living beings; the cause behind the disorder being abnormalities in the chromosomes. Chromosome is defined as an organised structure of DNA, RNA, protein and is the carrier of genes in the living beings. There are a varied number of disorders caused by the chromosome abnormalities and similarly all have different extra chromosome disorder symptoms.
Names of the disorders include- the Down syndrome (or trisomy 21), the Patau syndrome (trisomy 13), the Edward’s syndrome (trisomy 18), the Klienefelter syndrome (47, XXY), the (47, XYY) males, the trisomy X etc. All these disorders are caused due to different types of chromosomal alterations or abnormalities during chromosome disjunction.
Down Syndrome (Trisomy 21)
This syndrome is characterised by the presence of all or part of a third copy of the chromosome 21 in each cell. According to estimates, about 1 in every 691 babies in the US is born with this syndrome each year. The signs or symptoms of this syndrome include:
- Individuals with DS often suffer from some sort of intellectual/ mental disability. They have an IQ ranging between a 50- 70. Also individuals with DS have been found to have speech delays.
- The incidence of congenital heart disease is also found to be up to 50% in new born babies with the Down syndrome.
- Having varied number of hearing disorders, eye disorders, thyroid disorders and gastrointestinal issues are also signs of the Down syndrome.
Patau Syndrome (Trisomy 13)
In trisomy 13 there are three copies of the number 13 chromosome in the cells of the person suffering from the Patau syndrome. The trisomy 13 is associated with a set of recognisable physical features which help in diagnosing the syndrome. Some of the symptoms of the disorder include- small head and/ or eye sizes, an absence of an eye or a faulty retina, a cleft lip to cleft palate and varied ear shape etc.
Klienfelter Syndrome (47, XXY)
This is a genetic disorder which is associated with the presence of at least one extra X chromosome in the standard human male karyotype. The females have an XX chromosome makeup while males have an XY chromosome makeup. This syndrome implies that the individual has two X chromosomes and at least one Y chromosome. The symptoms of this syndrome are:
- The males have small testes and produce less testosterone as compared to the males who do not have this disorder.
- The males with the syndrome also show signs of breast enlargement and delayed/ incomplete puberty.
- Reduced facial/ body hair and infertility (inability to produce children biologically) are also the signs of the syndrome.