What are some chromosome 9 disorders?

Every living species has two types of cells, somatic cells (diploid) which are responsible for regeneration and replication and gametic (haploid) cells which are responsible for reproduction in the body. The chromosomes are the genetic material present in the nucleus of the cell which is a condensed form of double stranded helical DNA (deoxyribonucleic acid) and histone proteins. The cells have 46 chromosomes (23 pairs) in which, 22 pairs are called autosomes and 23rd pair is the sex chromosomes which determines the sex of the offspring. The sex chromosome in the male is denoted as XY and female sex chromosome is denoted as XX. Haploid cells are those which have half the number of chromosomes than parent cell (n). Whereas, diploid cells are those which have same number of chromosome like their parents (2n)

The genetic disease associated with the change in number of chromosomes is called numerical chromosomal aberration. These aberrations are caused due to missegregation during cell division. Types of numerical abberations are:

1. Trisomy: Due to error in metaphase, one extra chromosome is transferred to the daughter cell (2n+1). It is represented as (3n). 
2. Monosomy: The species with a single set of chromosomes. It is represented as (n). They are also called haploid in some cases. 
3.  Polyploidy: when the set of chromosomes are more than 2.
4. Tetrasomy: when 2 extra chromosomes are transferred to the daughter cell during cell division (2n+2)