Hypophosphatemia is a dominant genetic disorder caused by a deficiency of phosph

The Punnett square is pretty easy for this question. X-linked genetic disorders can either be recessive or dominant. In this example we can conclude that we are dealing with a dominant disorder because when the mom passes on the disorder half of her offspring will also have the disorder. If the X-linked trait was recessive then the mom's offspring would only be carriers, not actually expressing the disorder. Dad (the small a represents the trait for the disorder): Xa Y X XXa XY X XXa XY Mom: X Y Xa XXa XY X XX XY

i think is a X linked , female gets one X from her mom and one X from dad , so when her DAD's X is dominant means it may occur.

X is consider be the chromosome for Hypophosphatemia

If male having Hypophosphatemia

Xy * Female xx =>F1 Xx Xx xy xy

now the daughter has Xx Hypophosphatemia cross with

Xx * xy => Xx Xy xx xy

50% of population having the Hypophosphatemia

I cant draw a punnet square on here but if you imagine that the mother has the genotype Ee as she is a carrier. The father has the genotype E/ as he only has one X chromosome and it is unaffected.

There are three possible genotypes for the children...

EE ........ Ee ........ E / ........ e /

Female ..... Female .... Male ...... Male affected

Unaffected ....Carrier.... .Unaffected..... .

So you have a one in four chance (25%) that the child will inherit the disorder, the probability that the child will not inherit the e allele, is one in two, or 50%.

The pattern of inheritance on a sex linked (recessive) trait is that it is usually seen in males, even if both parents are unaffected.

It is only seen in females if the father has the disease, as she must recieve an X chromosome from him.

It cannot be passed from an unaffected father to a son, so if a son has the disease and the father does not then the defective allele must have come from the mother, who is by definiton a carrier.