Overview of Type I Osteogenesis Imperfecta
Type 1 osteogenesis imperfecta is one of the many subtypes of osteogenesis imperfecta, a hereditary condition brought about by genetic mutations exerting its effect on the production of type 1 collagen in the human body. It is the mildest form among the many types of osteogenesis imperfecta. And in some patients, it is so mild that the condition is not diagnosed until later in life. Other names of type I osteogenesis imperfecta are osteogenesis imperfecta tarda and Van der Hoeve syndrome.
The maintenance of bony structures and connective tissues in the body such as ligaments and tendons is the main responsibility of type 1 collagen. The production of Type I collagen depends on COL1A1 and COL1A2 genes. In the case of type 1 osteogenesis imperfecta, mutated COL1A1 and COL1A2 genes result in a decrease in the amount of type 1 collagen.
The decrease in type 1 collagen causes weakening of the bones, tendons, ligaments and other supporting structures in the body which translates to the signs and symptoms exhibited and felt by the patient with type 1 osteogenesis imperfecta. This genetic mutation does not cause abnormalities in the type 1 collagen but rather, it significantly decreases the amount produced. This is a differentiating characteristic of type 1 from the other types, since other forms of osteogenesis imperfecta result from abnormalities in the type 1 collagen itself.
Type I osteogenesis imperfecta is inherited through an autosomal dominant pattern. Simply put, one abnormal gene from one affected parent is enough for a child to inherit the condition. In some instances where neither parent is affected, the condition is acquired through new, spontaneous genetic mutations.