一罕见成骨不全IV型的基因诊断

目的对一疑似成骨不全IV型或其他类型的患儿实施基因诊断，以揭示患儿发病及频繁骨折的内在原因，为今后实施对症治疗和产前基因诊断创造必要的前提条件。方法对经症状、体征观察和x线检查初诊为成骨不全Iv型或其他类型的患儿，在抽取外周血制备DNA模板后，采用PCR、DNA直接测序法，对患儿的COLlAl基因进行突变检测，然后对所发现的突变进行分析和鉴定。结果在COLlAl基因的编码区内发现一典型的错义突变（c．823G〉C1／p．G275R），经查HGMD数据库证实为成骨不全Iv型的致病性突变。结论先证者为一罕见的成骨不全IV型患儿，所发现的p．G275R突变为中国人群首次报道的病理性突变。

Gene diagnosis of a rare case with osteogenesis imperfecta type IV

Objective The gene diagnosis of a child with suspected OI-IV （Osteogenesis Imperfecta type IV） or other types of diseases was made to reveal the internal cause of morbidity and frequent bone fracture, which creates the indispensable precondition for the prenatal gene diagnosis and symptomatic treatment in the future. Methods According to the observation of symptoms, signs and X-ray testing, the child was diagnosed preliminarily with OI-IV or other types. Then extracting DNA from peripheral blood, PCR-DNA direct sequencing were applied to detect the COL1A1 gene, and the mutation was analyzed and identified. Results A classical missense mutation （c.823G〉C/p.G275R） was found in the coding region of COL1A1 gene, which was confirmed a known mutation leading to OI-IV by HGMD. Conclusion The proband is a rare patient child suffered with OI-IV. The mutation ofp.G275R is a pathological mutation first reported in China.