This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Normal parent with 2 siblings having osteogenesis imperfecta. Pattern of inheritance is 
Select and explain. 
A. Mutation, B. Anticipation, C. Genomic imprinting, D. Germline mosacism
D: Germline mosacism
Answer: D: Germline mosacism 
Explanation: D i.e. Germline mosacism Differential expression of same gene depending on parent of origin is referred to as genomic imprinting. Germline (Gonadal) mosaicism results from a mutation only affecting cells destined to form gonads - postzygotically during early embryonic development. So the individual (parent) is phenotypically normal but can transmit the disease to offsprings through mutant gametesQ. And because the progenitor cells of gametes carry mutation, there is a high possibility that more than 1 child of such parent would be affected.