Question

I read that DiGeorge syndrome was rarely inherited and it is an autosomal dominant trait. Most cases occur because of random events in the sperm or egg or during development of the fetus. Can someone explain what those random events could be?

Answer 1

DiGeorge syndrome is an immunodeficiency disorder which is caused by chromosomal defects arising during the gestation period. The rare events associated with disorder are -

a) Deletion of a segment of chromosome 22 which consists of 30-40 essential genes either in the egg or the sperm. The reason for this deletion is not clear and hence it is considered as rare. The frequency of this rare event of deletion is 1/10

b) There are very low chances of passing on this disease to next generation. Thus it is also a rare event and its frequency of occurrence is 1 in 100.