Abstract
Background: Osteogenesis imperfecta (OI) is a rare hereditary connective tissue disease. It is mainly associated with pathogenic variants in COL1A1 or COL1A2. Patients with OI usually have repeated history of bone fractures. Besides, osteogenesis imperfecta is associated with some cardiovascular complications, such as aortic and mitral valve dysfunction, aneurysm and aortic dissection. But the relationship between these diseases has not been well studied.
Case Presentation: A 55-year-old man was admitted to our hospital mainly due to “dizziness for 2 hours”. He had a 4-month history of hypertension and a history of smoking for more than 20 years. He had no history of drinking alcohol. He had hunchback and O-type legs. Besides, the patient and some of his relatives had a history of repeated brittle fractures,which was considered as “osteogenesis imperfecta”. The clinical manifestation of OI in this family varies to a certain extent, from simple tooth disintegration to severe fracture deformity. The most serious patient of his family was unable to walk. CT and MRI revealed multiple systemic arteriosclerosis, including vertebral artery, posterior inferior cerebellar artery, cervical artery, and bilateral cerebellar multiple lacunar cerebral infarction. The blood sample of the patient was tested by whole exome sequencing, and the saliva samples of the patient’s family members were tested by Sanger sequencing. A mutation c.3159 + 2T > A was detected in COL1A2 gene associated with OI, also found in the other affected family members, which had not been reported before. It was a segregating mutation in the family. The clinical severity of the family members was heterogeneous.
Discussion:
This case is worth learning from the following aspects: 1. A pathogenic heterozygous mutation, c.3159 + 2T > A was detected in COL1A2 gene in the patient with OI, which is not reported in previous cases of OI. 2. The clinical manifestation of OI in this family varies to a certain extent, from simple tooth disintegration to severe fracture deformity. The most serious patient of his family was unable to walk. It presented the clinical heterogeneity of OI. Further basic researh on the mutation site of related gene of OI are needed. 3. We found the possibility of developing cerebral atherosclerosis in patients with OI. Therefore, patients with OI should give up smooking, exercise properly and keep on a low fat diet. They should pay attention to control blood pressure and blood lipid so as to reduce the risk of atherosclerosis.
Conclusion: A c.3159 + 2T>A mutation in COL1A2 gene detected by whole exome sequencing was the causing reason of OI, the discovery enriched the gene mutation spectrum of OI. We also found that OI may have relationship with premature atherosclerosis, and the abnormal bones of the cervical spine may lead to vertebrobasilar ischemia.
Analysis of the Genetic Characteristics of a Chinese Family With Otosclerosis
