Chromosomes

What are Chromosomes

Chromosomes are the structures that hold genes. Genes are the individual instructions our bodies use to develop and function and control physical and medical characteristics about our body. For example: Hair colour, Eye colour, blood type and so on.

Chromosomes exist in every cell of our body, whether it is a skin cell, blood cell or liver cell. In the center of most cells is a structure called the nucleus, chromosomes are located in here.

How many Chromosomes do we have?

In a human cell that are usually 46 (23 pairs). These hold an estimated total of 25,000 genes.
One set of 23 chromosomes is inherited from the mother, the other set of 23 from the father.

Chromosome Abnormalities

Chromosome Abnormalities can be categorised into 2 groups, numerical and structural abnormalities.

1) Numerical Abnormalities

When somebody is missing on the chromosomes from a pair, the condition is called monosomy. When somebody has more than 2 chromosomes instead of a pair, the condition is called trisomy.

2) Structural Abnormalities

The structure of the chromosome can be altered, this can cause:

  • Deletions: A section of the chromosome is missing or deleted
  • Duplications: A section of the chromosome is duplicated, which means there is extra genetic material.
  • Translocation: A section of one chromosome is transferred to another chromosome.

Chloe has a duplication on chromosome 9 as well as having a fairly large deletion on chromosome 10.

The imbalances have been considered de novo (not inherited from parents) through tests we have had carried out so far.