OBJECTIVETo detect potential mutations of COL1A1 and COL1A2 genes in four Chinese pedigrees affected with osteogenesis imperfecta (OI) and provide prenatal diagnosis for a fetus at 18th gestational week.

METHODSAll coding regions and exon/intron boundaries of the COL1A1 and COL1A2 genes were analyzed with targeted next-generation sequencing (NGS). Suspected mutations were confirmed with Sanger sequencing in the probands, unaffected relatives and 200 unrelated healthy individuals. Prenatal diagnosis for a high-risk fetus was carried out through Sanger sequencing.

RESULTSThe probands of families 1 and 2 have respectively carried a c.760G>A (p.Gly254Arg) and a c.608G>T (p.Gly203Val) mutation of the COL1A1 gene. For family 3, the proband and his daughter have carried a novel c.299-1G>C splicing mutation of the COL1A1 gene. The same mutation was not found in the fetus of this family. For family 4, the proband has carried a novel c.1990G>C (p.Gly664Arg) mutation of the COL1A2 gene. The four mutations were not found in the unaffected relatives and 200 unrelated healthy individuals.

CONCLUSIONThe mutations of the COL1A1 and COL1A2 genes probably underlie the disease in the four families. NGS combined with Sanger sequencing can provide an effective and accurate method for their genetic and prenatal diagnosis.