Objective This study was to identify Proteolipid protein 1 (PLP1) mutations in 33 unrelated Chinese patients (P1-33) with Pelizaeus-Merzbacher disease (PMD) and prenatal diagnosis of 5 fetuses in 3 Chinese families with PMD probands.Methods Genomic DNA was extracted from peripheral bloods samples.At 19 or 20 weeks gestation, amniotic fluid sampling (AFS) was performed.Gene dosage was determined by Multiplex Ligation-dependent Probe Amplification (MLPA).All 7 exons and exon-intron boundaries of PLP1 gene were amplified and analyzed by direct DNA sequencing.Results Of these 33 patients, there were 19 transitional, 11 classical, and 3 congenital PMD according to the clinical and radiological presentation.PLP1 duplications were identified in patients 1-23 with PMD, account for 69.7% (23/33).Their mothers were PLP1 duplications carriers except P23mother was wildtype.Six hemizygous missense mutations including c.517C>T (p.P173S), c.709T>G(p.F237V), c.623G>T(p.G208V), c.567C>T(p.T156I), c.353C>T(p.T117R) and c.646C>T(p.P214S) were found in Patients 24-29 with PMD (18.2%), and their mothers were showed to be a heterozygote of those mutation.For the results of prenatal diagnosis, in the family 1, For the prenatal diagnosis family 1, the 5 fetuses showed normal PLP1 dosage and chromosome analysis demonstrated 3 46,XX and 2 46,XY chromosome patterns, respectively.The fetus in family 2 revealed 3 cope of PLP1 which suggested a PLP1 duplication carrier after chromosome pattern was a 46,XX.In family 3, duplication of PLP1 was detected in the fetus imply as a PMD patient with 46,XY chromosome pattern.Conclusion We identified 23 genomic duplications and 6 missense mutation of PLP1 gene in 29 Chinese patients with PMD, account for 87.9% (29/33).Prenatal diagnoses for 5 fetuses in 3 PMD families were performed, which is useful and helpful for those families.This is the first report about PLPI mutations and prenatal diagnosis in PMD patients in mainland of China.