Although DiGeorge syndrome can be passed down through families, it often arises de novo, meaning the child has the syndrome, but neither parent does. DiGeorge syndrome is highly penetrant, meaning that having the variant on one chromosome ensures that you will have some symptoms. Given what you know so far about DiGeorge syndrome, which of the following is the most likely explanation? . A. An error occurs during maternal or paternal meiosis, creating a new variant.
B. This could only be explained if one of the parents has been misidentified.
C. One of the parents actually has the variant, but no symptoms.
D. Both parents are carriers of DiGeorge syndrome.

A

Explanation:

The correct answer would be that de novo incidences of DiGeorge syndrome occur as a result of errors during maternal or paternal meiosis, creating a new variant.

Since the syndrome has high penetrance, it is highly unlikely that any of the parents would be misidentified or that one of the parents has the variant without symptoms. It is also highly improbable that both parents would be carriers because if they do, they will definitely show some symptoms.

Hence, the most likely explanation is that the variant emerges as a result of errors during maternal or paternal meiosis leading to the formation of a gamete with the variant.

The correct option is A

"a.) well–developed vascular system."