When a person has a extra chromosomal material, like in 15q26 overgrowth syndrome, it is like a section of the body's instruction manual is not correct. People with 15q26 overgrowth syndrome have four copies of the q26 section of chromosome 15 rather than the usual two.Ī person's chromosomes are like the body's instruction manual. “Tetra” means 4, and “somy” refers to the chromosomes. The condition is sometimes called “Tetrasomy 15q26 overgrowth syndrome”. 15q26 overgrowth syndrome is a disorder caused when a person has too many copies of section 26 on the q arm of chromosome 15 – this is where “15q26” comes from. The arms are broken down into even smaller sections which are designated by numbers.
The short arm of a chromosome is called the “p arm” while the long arm is called the “q arm”. Females have two X chromosomes (XX) and males have one X chromosome and one Y chromosome (XY).Įach chromosome is made up of 2 sections, called “arms” – a short arm and a long arm. The last pair are called the sex chromosomes and they determine our gender. The first 22 pairs of chromosomes are numbered 1-22, and they are the same in males and females. One chromosome of each pair is inherited from our mother, and the other is inherited from our father. Human cells usually contain 46 chromosomes, or 23 pairs of chromosomes. Chromosomes are found in almost every cell of a person’s body. Chromosomes contain our body's genetic information. 15q26 overgrowth syndrome is a chromosome disorder.