Sex linked recessive diseases

In this question the answer is A. But the sex linked recessive diseases are lethal for infant women and it only cause disease in males. Can someone explain this?


thats is because you cant get it to women if it’s lethal in infancy; the only possible way to pass the disease is in the case if there is a carrier woman and a healthy man in this case only males can inherit the disease if they get the chromosome X that carries the recessive allele.

hope that helps.

it is a nice question. can u share the resource. appreciate it.

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Its from Fiacenza imat practise book

It means that the embryo of females donot develop and they die befire birth? Because if this is the case the we can say that sex linked recessive diseases are a cause of death of only male infants

@Walina Hey!
We know that man has only one X chromosome and the only chromosome that can contain the recessive allele is X.
If a man has this disease he would die. So we need a healthy man here.
And as the woman is XX, she can have one recessive allele so that she can be a carrier; cause if two recessive alleles were present the woman will die too!
And based on this situation, the only way that this disorder can be lethal in infancy is that we have a male infant. Cause if we had a female infant she wouldn’t die and she was only a carrier cause her father was healthy.

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are u sure it has no imat past papers questions?

Yes it has many imat past paper questions