Is it possible for a mother (Hh) and a father (hh), to have 4 kids, out of which non (hh)?

Question

I am doing a family pedigree to retrace the steps of inherited High blood pressure (HBP).

What I found was that one of my aunts who is heterozygous for the trait (Hh) married a man homzygous recessive (hh). Together they had 4 children. Non of the children have highblood pressure.

Is this possible?
Out of 4 children, do 1/2 have to always be (Hh) and 1/2 (hh).
Can you not have a family where, although parents outcome is Hh and hh, that their children are not affected?

Highblood pressure is mulifactoral inheritence. Therefore, environment could also play a role in it.
- the father has HBP (hh) but could it be that be got it at a later stage in his life, after children were born, or he got it from the enviornment (stress, tension, diet, sleep)?

Can anyone help me with this pedigree problem...If you are unsure, do not answer. Only if you are certain, let me know.

Answer 1

Out of 4 children, 1/2 do not always have to be hh. Nature doesn't work that way. Each child is conceived and receives those trait individually. No one in Nature keeps track of how many Hh there are, then tries to even up the traits of the children. They can all be either Hh or hh, or you can have a combination.

You touched on a major factor when you questioned what caused the HTN (hyertension). If your aunt is overweight, if she is a diabetic, if she's sedentary with a crummy diet, she may have HTN. That doesn't mean her children will have it. They may have a propensity toward it, but if they live a healthy life-style, it may never surface. Also, when did your aunt or uncle get the HTN? If it was later in life, perhaps the children will get it at a later age.

One of your questions seems to infer that if the father got HTN after the children were born, then they wouldn't have inherited it. If there is some genetic factor involved, it wouldn't matter when his HTN symptoms surfaced. It would still be carried in the genes and the children might still have that gene.

You're dealing with many factors here, the main one being if the aunt or uncle actually have a genetic predisposition to HTN, or if they have it primarily because of poor lifestyle choices. It seems you will have more than one hypothesis, and your conclusion will be a lucky, somewhat educated guess. :)

Answer 2

Yes, here is the pattern box

H h (mother)

h Hh hh Children 1 and 2

h hH hh children 3 and 4.

(father)

This box shows that the possibility of children having high blood pressure, if it is homozygous is 75%, but if it is heterzygous, (needs to have both big H, or for males, one Big H,) then there is a 50% chance that their children will have high blood pressure.

Answer 3

Yes.

Each kid has an indpendent chance of being Hh. so each of the four had a 50/50 chance of being Hh.

The odds of four children all being Hh is 1:16 (6.5%), so they were lucky.

Answer 4

No, the outcome will always be 2 have hh and 2 have Hh, sorry.

Answer 5

yes, it's possible. with each pregnancy, each child has a 50/50 percentage of being either Hh or hh. so it couild go both ways. it was just lucky that it turned out all 4 are Hh.