Genetic Conditions

• Genetic conditions

  genetic conditions are conditions caused by a fault with genes or chromosomes ( a genetic fault). Some genetic conditions (but not all) are INHERITED; inherited conditions are passed down from parent to child.
• examples of genetic conditions

  • haemophilia
  • cystic fibrosis
  • huntington’s disease
  • down’s syndrome
• Haemophilia


  A condition caused by

  a Problem with the Blood Clotting Mechanism.

  Sufferers are at risk of Excessive Bleeding, even from very small wounds or bruising.

  It is a sex-linked or inherited condition

  caused by a Recessive Allele on the X Chromosome.

  Most people with haemophilia are males with the genotype XhY
• Cystic Fibrosis

  Individuals with Cystic Fibrosis have

  frequent and serious lung infections

  and problems with food digestion.

  It is caused by a Recessive Allele, so affected individuals must be Homozygous Recessive.
• Huntington’s Disease 


  Individuals with Huntington’s Disease have

  Progressive Brain Deterioration,

  which usually becomes apparent in middle age.

  It is fatal and there is no cure.

  It is caused by the presence of a Dominant Allele
• Down’s syndrome 


  caused by presence of a extra chromosome (so 47 not 46)

  humans normally have 23 chromosomes in each gamete (sperm or egg)

  occasionally, gametes are formed with 24 chromosomes, so if one of these gametes is involved in fertilisation with a ‘normal’ gamete the. the child produced will have 47 chromosomes

  individuals with this conditions have easily identified facial features particular to the condition, reduced muscle tone and reduced cognitive development.
• Inherited genetic conditions:

  • haemophilia
  • cystic fibrosis
  • huntington’s disease
• NON-inherited genetic condition: (caused by a mistake during gamete formation)

  Downs Syndrome

  it is not inherited by the passing of a faulty gene or chromosome from a parent to child.

  individuals with down’s syndrome can be identified by counting The Number of Chromosomes in a Karyotpe