[Application of Karyomapping for the prenatal diagnosis of five families affected with facioscapulohumerial muscular dystrophy type 1]. 
To assess the value of Karyomapping for the prenatal diagnosis of facioscapulohumerial muscular dystrophy type 1 (FSHD1).  Peripheral blood and chorionic villi samples were collected from five families affected with FSHD1.  Linkage-based diagnosis was carried out by using the Karyomapping method.  Diagnosis for two fetal samples was carried out with the next-generation optical mapping system.  The results of Karyomapping showed that three fetuses inherited the risky 4q35 region of the proband and two fetuses did not.  The fetuses of families 1 and 2 received further diagnosis by the next-generation optical mapping system, and the results were consistent with those of Karyomapping.  Karyomapping has enabled prenatal diagnosis for the five families affected with FSHD1.  The method was faster and simpler compared with conventional strategies, though its feasibility still needs further validation.  Since there were no SNP loci designed on the Karyomap chip for the DUX4 gene and its 3' flanking regions, misjudgment due to chromosomal recombination could not be completely eliminated.  The accuracy of this method still needs further validation.