Heredity (30%):
The cause of this disease is unknown, and it is a congenital developmental disorder. The incidence of male and female is equal, which can be divided into congenital and delayed. Congenital type refers to the onset in uterus, which can be further divided into fetal type and infant type. Serious illness, mostly death, or short-term postpartum death, is autosomal recessive inheritance. Delayed type is light and can be divided into childhood type and adult type. Most patients can survive for a long time and have autosomal dominant inheritance.
The disease is autosomal dominant or recessive, and it can be sporadic. The blue sclera transmittance is 100%, and the hearing loss changes with age. Most sporadic cases are caused by new mutations, which are often related to elderly parents.
Gene mutation (30%):
The occurrence of osteogenesis imperfecta is mainly due to the mutation of α 1 or α2 procollagen (Pro-α 1 or Pro-α2) chains (i.e. COL 1A 1 and COL 1A2) constituting type I collagen, which leads to the disorder of synthesis of type I collagen.
Other factors (30%):
Mainly manifested in the skin, tendons, bones, cartilage and other connective tissues, the main component of collagen hypoplasia. The author has reported that there are too many proline components in collagen tissue of patients, and the peak value of proline in blood is lower than that of normal children after oral administration of proline.
In terms of bones, osteoblast production is reduced or activity is reduced, and alkaline phosphatase cannot be produced, or both, so that subperiosteal osteogenesis and endochondral osteogenesis are blocked, trabecular bone in cancellous bone and cortical bone becomes smaller, calcification is incomplete, and groups of chondrocytes, chondroid tissues and calcified osteoid tissues can still be seen, while calcium salt deposition of bone is normal. The above lesions cause bone fragility and osteomalacia.
In other words, brittle bone disease can be inherited, and 30% brittle bone disease is hereditary.