中文摘要：

成骨 imperfecta (OI，也已知的同样易碎的骨头疾病) 主要被变化在二种类型引起我编码类型的 pro-1 (I) 和 pro-2 (I) 链的骨胶原基因， COL1A1 和 COL1A2 我骨胶原分别地。有正染色体的主导的 OI 的二个中国家庭被识别并且描绘。连接分析在染色体 7q21.3-q22.1 上揭示了两个家庭的连接到 COL1A2。Mutational 分析用直接 DNA 顺序分析被执行。二个新奇错误感觉变化， c.3350A > G 和 c.3305G > C，在 exon 被识别在二个家庭的 49 COL1A2 分别地。c.3305G > C 变化在 codon 由丙氨酸残余(A) 导致了 glycine 残余(G) 的替换 1102 (p.G1102A ) ，它被发现在另外的家庭被变异进丝氨酸(S) ， argine (R) ，丁氨二酸酸(D) ，或缬氨酸(V) 。c.3350A > G 变体可以是导致 p.Y1117C 的一个 de novo 变化。两个变化在各自的家庭与 OI 共同分离，并且没在 100 正常控制被发现。G1102 和 Y1117 残余高度 evolutionarily 从 zebrafish 被保存到人。Mutational 分析没在 COX-2 基因(OI 的修饰词基因) 识别任何变化。这研究识别引起 OI 的二新奇变化 p.G1102A 和 p.Y1117C，显著地扩展引起 OI 的 COL1A2 变化的光谱，并且有在 OI 的出生前的诊断的一个重要含意。

英文摘要：

Osteogenesis imperfecta（OI,also known as brittle bone disease）is caused mostly by mutations in two type I collagen genes,COL1A1 and COLIA2 encoding the pro-α1（I）and pro-α2（I）chains of type I collagen,respectively.Two Chinese families with autosomal dominant OI were identified and characterized.Linkage analysis revealed linkage of both families to COL1A2 on chromosome 7q21.3-q22.1.Mutational analysis was carried out using direct DNA sequence analysis.Two novel missense mutations,c.3350AG and c.3305GC,were identified in exon 49 of COL1A2 in the two families,respectively.The c.3305GC mutation resulted in substitution of a glycine residue（G）by an alanine residue（A）at codon 1102（p.G1102A）,which was found to be mutated into serine（S）,argine（R）,aspartic acid（D）,or valine（V）in other families.The c.3350AG variant may be a de novo mutation resulting in p.Y1117C.Both mutations co-segregated with OI in respective families,and were not found in 100 normal controls.The G1102 and Y1117 residues were evolutionarily highly conserved from zebrafish to humans.Mutational analysis did not identify any mutation in the COX-2 gene（a modifier gene of OI）.This study identifies two novel mutations p.G1102A and p.Y1117C that cause OI,significantly expands the spectrum of COL1A2 mutations causing OI,and has a significant implication in prenatal diagnosis of OI.