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
Locus heterogeneity is a feature of which of the following? 
Select and explain. 
A. Familial adenomatous polyposis, B. MENU, C. Osteogenesis imperfecta, D. All of the above
C: Osteogenesis imperfecta
Answer: C: Osteogenesis imperfecta 
Explanation: TYPES OF HETEROGENEITY are
A. Allelic Heterogeneity,
B. Phenotypic Heterogeneity,
C. Locus or Nonallelic Heterogeneity.
Nonallelic or locus heterogeneity refers to the situation in which a similar disease phenotype results from mutations at different genetic loci. E.g Osteogenesis imperfecta, Albinism, Muscular dystrophy syndromes (dystrophin, most common cause of mus dystrophy and has large gene size).