Ultrasonography of a 26yearold woman at 16 weeks gestation shows fetal findings consistent with osteogenesis imperfecta, type II. The woman had a previous fetus affected with the same condition. The woman and her husband are healthy and have no obvious clinical characteristics of osteogenesis imperfecta. Which of the following is the MOST likely explanation for this recurrence?
A. autosomal recessive inheritance
B. de novo mutation
C. germline mosaicism
D. incomplete penetrance