PROTEOLIPID PROTEIN 1 GENE MUTATION IN CHINESE PATIENTS WITH PELIZAEUS-MERZBACHER DISEASE

Abstract

INTRODUCTION: Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder that presents with nystagmus, impaired motor development, ataxia, and progressive spasticity. OBJECTIVE: The objective of this study was to analyze the proteolipid protein 1 (PLP1) gene in 6 Chinese patients with PMD. METHODS: Six unrelated Chinese patients had PMD (P1–P6), and 14 individuals were from family P2. Of these 6 patients, 3 had transitional, 2 had classical, and 1 had connate PMD according to the clinical and MRI features. Genomic DNA was extracted from peripheral blood samples. Gene dosage was determined by multiplex ligation-dependent probe amplification. All 7 exons and exon-intron boundaries of PLP1 gene were amplified and analyzed by direct DNA sequencing. RESULTS: PLP1 duplications were identified in patients 1 through 4 with PMD. Their mothers were PLP1 duplication carriers. Both duplication carriers and normal genotypes of PLP1 were identified in the family members of patient P2. A c.517C → T (p. P173S) hemizygous missense mutation in exon 4 was found in patient 5, and his mother was a heterozygote of this mutation. CONCLUSIONS: We identified 4 gene duplications and 1 missense mutation (p. P173S) of PLP1 gene in 5 Chinese patients with PMD. This is the first report about PLP1 mutations in patients with PMD in China.