Exome capture sequencing identifies a novel CCM1 mutation in a Chinese family with multiple cerebral cavernous malformations

Abstract

Purpose: Cerebral cavernous malformations (CCMs) are vascular anomalies predominantly in the central nervous system but may include lesions in other tissues, such as the retina, skin and liver. The main clinical manifestations include seizures, hemorrhage, recurrent headaches and focal neurological deficits. Previous studies of familial CCMs (FCCMs) have mainly reported in Hispanic and Caucasian cases. Here, we report on FCCMs in a Chinese family further characterized by a novel CCM1 gene mutation. Materials and methods: We investigated clinical and neuroradiological features of a Chinese family of 30 members. Furthermore, we used exome capture sequencing to identify the causing gene. The CCM1 mRNA expression level in three patients of the family and 10 wild-type healthy individuals were detected by real-time quantitative polymerase chain reaction (real-time RT-PCR). Results: Brain magnetic resonance imaging demonstrated multiple intracranial lesions in seven members. The clinical manifestation of CCM was found in five of these cases, including recurrent headaches, weakness, hemorrhage and seizures. Moreover, we identified a novel nonsense mutation c.1159G>T (p. E387*) in the CCM1 gene in the pedigree. Based on real-time RT-PCR results, we have found that the CCM1 mRNA expression level in three patients was reduced by 35% than that in wild-type healthy individuals. Conclusions: Our finding suggests that the novel nonsense mutation c.1159G>T in CCM1 gene is associated with FCCM, and that CCM1 haploinsufficiency may be the underlying mechanism of CCMs. Furthermore, it also demonstrates that exome capture sequencing is an efficient and direct diagnostic tool to identify causes of genetically heterogeneous diseases.

KEYWORDS:

• cerebral cavernous malformations
• CCM1
• mRNA decay
• exome capture sequencing

Acknowledgements

The authors would like to thank the patient and relatives for participating in this study.

Declaration of Interest

The authors report no conflict of interest. The work was supported by the grants from the National Natural Science Foundation of China grant 81530037 and 81471158 (to Dr Yuming Xu) and the National Natural Science Foundation of China grant U1404311 (to Dr Changhe Shi).