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Date of last update: 9/9/2017.

Forum Name: Pediatric Topics

Question: daltonisme son

 archi - Thu Jun 24, 2004 6:54 am

if a normal woman marry a daltonien guy what will be the children ? normal children or daltonien too?
 Dr. Tamer Fouad - Thu Jun 24, 2004 4:00 pm

User avatar Dalton's disease is sex-linked recessive. The term "sex-linked recessive" means that an abnormal gene on the X chromosome from each parent is required to cause the disease in females since the female has 2 X chromosomes. In males there is only one X chromosome, therefore, a single recessive gene on the X chromosome will cause the disease.

So to solve your problem:

X=Dalton's gene
x=Normal gene

Man has Dalton: + Woman not carrier
Xy + xx = Xx, Xx, xy, xy

Hence none of their children will have Dalton's but any girls they have will be carriers.

Man has Dalton + Woman carrier
Xy + Xx = XX, Xx, Xy, xy

Here, half their boys will have Dalton's and the other half will be carriers. Half their daughters will be carriers and the other half completely normal.

The couple need genetic counsuling before they marry.

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