Question

A couple (both of which are normal) has a son that has Duchenne muscular dystrophy. This is a rare sex-linked recessive disorder which causes muscle deterioration that almost always affects boys. The parents believe that the hospital mixed their child up with a normal child and sue the hospital. You have once again been called as an expert in genetics to testify. What do you tell the jury? Is it possible that these are the biological parents or did the hospital make a mistake? Fully explain your answer.

Answer 1

Duchenne muscular dystrophy is caused by X-linked recessive inheritance. Though both parents are similar, if mother might be the carrier for the disease, 50% of their male children will have the disorder. Because, male children will get X-chromosome from mother only.

The disease may not be inherited by any means of physica cause either in the hospital or some where else. It is not the hospital mistake, it is caused by the parents only as they are biological parents.

See the below punner checker board for your clarification.

XD= Normal allele present on the X-chromosome

Xd= diseased allele present on the X=chromosome

XD Xd (Normal mother) x (normal father) XD Y---------Parents

	XD	Y
XD	XD XD (normal daughter)	XD Y (normal son)
Xd	XD Xd (normall but carrier daughter)	Xd Y (diseased son)