A Genetic disease is known as of recessive transmission related to X when

  • the abnormal Gène is on the Chromosome sexual X
  • the presence of only one abnormal Gène is sufficient so that the disease is expressed at a boy
  • the presence of two genes is necessary so that the disease is expressed at a fille.
The abnormal Gène is transmitted either by the father or by the mother.
  • If the gene is transmitted by the father, this one is obligatorily sick
  • If the gene is transmitted by the mother that Ci is: either generally hétérozygote i.e. it has a healthy gene and a sick gene, or it is sick and it is thus homozygote
During the gamétogenèse, the male or female cells pass from 2n Chromosome S (cell diploïde) to N Chromosome (haploid cell). The abnormal gene is thus present in half of the gamètes.
The characteristics of a genetic disease with recessive transmission related to X are the following ones:
  • It reaches the men almost exclusively.
  • the father does not transmit his disease to its boy (except if his wife is carrying gene).
But to be carrying gene inevitably does not mean to be sick, the demonstrations of a genetic disease depend on its Pénétrance and the Variabilité of its expression

General outline of the recessive transmission related to X

In the diagrams the gamètes carrying normal gene are blue, the gamètes carrying abnormal gene are red. The sick people are red, the nonsick people but carrying gene are violets, the people noncarrying gene are blue

Union of a sick man and a noncarrying healthy woman

Like this diagram shows it:
  • No boy will be reached since Y is obligatorily transmitted to them.
  • All the girls will be carrying but healthy. They will transmit all the disease. They are called Conductrice S
  • 1/2 to have a child noncarrying the gene anormal

Union of a healthy man and a carrying woman

Like this diagram shows it, this couple has a risk with each pregnancy
  • 1/2 to have a boy carrying abnormal gene thus sick
  • 1/2 to have a boy noncarrying abnormal gene thus healthy
  • 1/2 to have a girl carrying abnormal gene thus conducting
  • 1/2 to have a girl noncarrying abnormal gene

Union of a sick man and carrying

Like this diagram shows it:
  • 1/2 to have a boy carrying abnormal gene thus sick
  • 1/2 to have a boy noncarrying abnormal gene thus healthy
  • 1/2 to have a girl carrying abnormal gene thus conducting
  • 1/2 to have a girl carrying two abnormal genes thus sick

Union of a patient and a patient

All the children of this couple will be sick.

General base of the genetic council in the recessive diseases related to X

In genetics, the proposer nominates the person reached of the genetic disease from which one makes the genetic Conseil.

Relative of a proposer

Phratry of a proposer

Descent of a proposer

Examples

Sources

See too

Random links:Sphyrnidae | Ray Evans | Alexandre Georges | Psychological operations | Kō No Moronao