Identification of proteolipid protein 1 gene duplication by multiplex ligation-dependent probe amplification: first report of genetically confirmed family of Pelizaeus-Merzbacher disease in Korea.
Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder with a prototype of a dysmyelinating leukodystrophy that is caused by a mutation in the proteolipid protein 1 (PLP1) gene on the long arm of the X chromosome in band Xq22. This mutation results in abnormal expression or production of PLP. We here present a Korean boy with spastic quadriplegia, horizontal nystagmus, saccadic gaze, intentional tremor, head titubation, ataxia, and developmental delay. The brain magnetic resonance imaging (MRI) showed abnormally high signal intensities in the white matter tract, including a subcortical U fiber on the T2-weighted and fluid attenuated inversion recovery (FLAIR) image. The chromosomal analysis was normal; however, duplication of the PLP1 gene in chromosome Xq22 was detected when the multiplex ligation-dependent probe amplification (MLPA) method was used. We also investigated the pedigree for a genetic study related to PMD. This case suggests that the duplication mutation of the PLP1 gene in patients with PMD results in a mild clinical form of the disorder that mimics the spastic quadriplegia of cerebral palsy.
Kim
Sei Joo
SJ
Department of Physical Medicine and Rehabilitation, College of Medicine, Korea University, Seoul, Korea.
Yoon
Joon Shik
JS
Baek
Hye Jin
HJ
Suh
Sang Il
SI
Bae
Sook Young
SY
Cho
Hyun-Jung
HJ
Ki
Chang-Seok
CS
D001921:Brain / Q000473:pathology*; D002675:Child, Preschool; D002874:Chromosome Mapping; D041321:Chromosomes, Human, X; D002658:Developmental Disabilities / Q000175:diagnosis / Q000235:genetics; D005091:Exons; D020440:Gene Duplication; D006801:Humans; D007723:Korea; D008279:Magnetic Resonance Imaging / Q000379:methods; D009154:Mutation; D018991:Myelin Proteolipid Protein / Q000235:genetics; D009186:Myelin Sheath / Q000737:chemistry; D020371:Pelizaeus-Merzbacher Disease / Q000175:diagnosis* / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*
D018991:Myelin Proteolipid Protein; C472930:PLP1 protein, human