CF Genetics and Probabilities

[Guest guest]

Hi all!

I've been following the discussion about genetics and CF. I've found this table

on the Web, and I think it may help a little bit.

Taken from:

http://www.aarc.org/patient_education/tips/cystfibr.html

Figure 1. Probability of Having a Child With Cystic Fibrosis

Parents Chance of

Unaffected Child Chance of

Child r Chance of

Child with CF

Unaffected + r 50% 50% 0

Two rs 25% 50% 25%

Unaffected + CF Patient 0 100% 0

r + CF Patient 0 50% 50%

My baby Agustin is a CFer (double Delta F508). That means, his Daddy Janko and

I are (at least) carriers. In fact, we are both carriers, and we both carry the

same (*single* copy of the) mutation. Therefore Agustin is homozygous DF508.

He inherited both our deffective copies of that gene. :-( If I carried another

mutation, and Agus had also been born with CF, he would have been heterozygous

DF508/ " my mutation " (provided Janko is a DF508 carrier).

Me might have had an unaffected child, and with the same chance of having a CFer

(25%). Or, we might have had a carrier, even with a higher likelihood, that is,

50%.

Besides, I am a carrier. That means that:

a.- Either my mother is a carrier OR my father was a carrier.

OR

b.- My mother is a carrier AND my father was a carrier.

It is NOT necessary that BOTH my mother AND my father are carriers for me to

have inherited the CF *single* copy of the mutation. Only one carrier parent is

enough.

Hope this helps.

Love,

M. M. Borro

Mom of Agustin, 7mo

trish@...