OBJECTIVETo diagnose achondroplasia prenatally by FGFR3 gene detection.

METHODSSeventy-eight fetuses affected by short-limb dysplasias were recruited. Umbilical blood sampling was employed to obtain fetal blood for karyotyping and FGFR3 gene detection. Genomic DNA was extracted, and the exon 10 of the FGFR3 gene was amplified. PCR amplicons were analyzed by DNA sequencing and restriction fragment length polymorphism with Bfm I. The FGFR3 exon 10 from the parents of the positive fetuses was screened by the same method.

RESULTSIn 78 fetuses affected with short-limb dysplasias, 8 cases had G1138A heterozygotic mutation and normal karyotype, and were diagnosed as achondroplasia. The other 70 fetuses had normal nucleotide at nucleotide 1138 in exon 10 of FGFR3, therefore were excluded from achondroplasia. Only one father in parents of the 8 achondroplasia fetuses also had the G1138A mutation.

CONCLUSIONAchondroplasia could be diagnosed prenatally in the fetuses affected with short-limb dysplasias by using PCR-RFLP and DNA sequencing of the exon 10 of the FGFR3 gene.