Pelizaeus-Merzbacher disease (PMD) is a rare, X-linked recessive disorder characterized by dysmyelination in the central nervous system. PMD results from deletion, mutation, or duplication of the proteolipid protein gene (PLP1) located at Xq22, leading to the failure of axon myelination by oligodendrocytes in the central nervous system. PMD may be suspected when there are clinical manifestations such as nystagmus, developmental delays, and spasticity, and genetic analysis can confirm the diagnosis. Further diagnostic manifestations of the disease include a lack of myelination on brain magnetic resonance (MR) imaging and aberrant N-acetyl aspartate (NAA) and choline concentrations that reflect axonal and myelination abnormalities on phroton MR spectroscopy. We report 5 cases of PMD (in 1 girl and 4 boys). PLP1 duplication was detected in 2 patients. Brain MR analyses and MR spectroscopy were performed for all the patients. The brain MR images showed white matter abnormalities typical of PMD, and the MR spectroscopic images showed diverse patterns of NAA, creatinine, and choline concentrations. We propose that MR spectroscopic analysis of metabolic alterations can aid the PMD diagnosis and can contribute to a better understanding of the pathogenesis of the disease.
Aspartic Acid ; Axons ; Brain ; Central Nervous System ; Choline ; Creatinine ; Humans ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Magnetics ; Magnets ; Muscle Spasticity ; Myelin Sheath ; Oligodendroglia ; Pelizaeus-Merzbacher Disease

Pelizaeus-Merzbacher disease (PMD) is a rare sudanophilic leukodystrophy with a reduced number of mature oligodendrocytes as well as diffuse central nervous system hypomyelination (dysmyelination) due to abnormal synthesis of proteolipid protein. PMD is characterized with pendular nystagmus, stridor, delay in psychomotor development, hypotonia, ataxia, athetosis and extrapyramidal signs. Abnormal high signal intensity is shown in the entire white matter of cerebrum and cerebellum at early stage by T2-weighted magnetic resonance imaging (MRI). We report two cases of PMD diagnosed with characteristic clinical manifestations and brain MRI findings.
Ataxia ; Athetosis ; Brain ; Central Nervous System ; Cerebellum ; Cerebrum ; Magnetic Resonance Imaging ; Muscle Hypotonia ; Nystagmus, Pathologic ; Oligodendroglia ; Pelizaeus-Merzbacher Disease* ; Respiratory Sounds

OBJECTIVEPelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive leukoencephalopathy. Few reports of PMD patients without genetic confirmation have been published in the mainland of China. The clinical and genetic features of a family with PMD were analyzed, which may contribute to definite diagnosis, genetic counseling and prenatal diagnosis of this rare hereditary disease in China.

METHODSClinical data of the proband and other family members as well as 14 DNA samples were collected. Clinical features including symptoms, signs and cranial MRI were analyzed. Multiplex ligation-dependent probe amplification (MLPA) assays were performed to detect PLP1 duplication, which helps identify the type of PLP1 mutation in this family and the genotype-phenotype correlations.

RESULTS(1) The proband and the other 3 male patients in the family presented with nystagmus, motor retardation followed by regression. The cranial MRI of proband showed evidence of poor myelination with diffused high signal in white matter region on T2-weighed image and reduced amount of white matter in volume, which is consistent with the typical features of cranial MRI in PMD. (2) PLP1duplication was identified in the proband. Combined with the clinical features of the proband and other patients in this family, the diagnosis of classic form of PMD was confirmed. Another 3 females with normal phenotype in the family were proved to be carriers of PLP1duplication.

CONCLUSIONS(1) The Classic form of PMD in this pedigree is resulted from the PLP1 duplication, which is consistent with the previously reported genotype-phenotype correlations; (2) The results serve as an evidence for reliable genetic counseling and prenatal diagnosis for this family. (3) MLPA, which is a newly developed method, is a rapid and reliable technique to detect the whole gene duplication of PLP1.

Adult ; DNA Probes ; Genes ; Genetic Association Studies ; Humans ; Infant ; Male ; Mutation ; Myelin Proteolipid Protein ; genetics ; Pedigree ; Pelizaeus-Merzbacher Disease ; genetics ; Phenotype

BACKGROUNDPelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder with symptoms including nystagmus, impaired motor development, ataxia, and progressive spasticity. The proteolipid protein 1 (PLP1) gene is the only pathogenic gene of PMD. Duplication of the PLP1 gene is the most frequent gene defect, accounting for 50%-70% of PMD cases, whereas point mutations in the coding sequence or the splice sites account for 10%-25% of PMD cases. This study aimed to identify PLP1 mutations in nine unrelated Chinese patients (P1-9) with PMD, and 14 subjects from the family of patient 2 were also described.

METHODSGenomic DNA was extracted from peripheral blood samples. Gene dosage was determined using the multiplex ligation-dependent probe amplification (MLPA). All 7 exons and exon-intron boundaries of the PLP1 gene were amplified and analyzed using direct DNA sequencing.

RESULTSOf these nine patients, there were four transitional, four classical, and one connatal PMD according to their clinical and radiological presentations. PLP1 duplications were identified in patients 1-7 with PMD. Their mothers were PLP1 duplications carriers as well. Both duplication carriers and normal genotypes of PLP1 were identified in the family members of patient 2. A c.517C > T (p. P173S) hemizygous missense mutation in exon 4 was found in patient 8 with PMD, and his mother was shown to be a heterozygote of this mutation.

CONCLUSIONSWe identified seven genomic duplications and one missense mutation (p. P173S) of the PLP1 gene in eight Chinese patients with PMD. This is the report about PLP1 mutations in PMD patients from the mainland of China.

Child, Preschool ; Female ; Gene Duplication ; Humans ; Infant ; Male ; Mutation ; Myelin Proteolipid Protein ; genetics ; Nucleic Acid Amplification Techniques ; Pelizaeus-Merzbacher Disease ; genetics ; Sequence Analysis, DNA

PURPOSE: Leukodystrophies have been defined as inherited metabolic disorders of myelin resulting in abnormal development or progressive destruction of the white matter. This study was performed to investigate the clinical manifestations and treatments of leukodystrophies in a single Korean tertiary center. METHODS: We retrospectively analysed the medical records of patients who had been diagnosed with leukodystrophy from May 1995 to May 2010 at the Asan Medical Center. RESULTS: During the 15-year study period, 36 cases of leukodystrophies were diagnosed with an verage age at symptom presentation of 49 months. Prominent symptoms at presentation were developmental delay (41%) and seizure (25%); however, nystagmus, developmental regression, hearing loss, gait disturbance, visual disturbance, attention deficit, hypotonia, hyperpigmentation, and hemiparesis were also observed. On MRI, periventricular involvement was noted frequently. The most common diagnoses were adrenoleukodystophy (25%), metachromatic leukodystrophy (11%), Krabbe disease (11%), and Pelizaeus-Merzbacher disease (8.3%). No final diagnosis was made in 14 cases (41%). Bone marrow transplantation was performed in 4 patients and showed favorable prognoses. CONCLUSION: Clinical features of leukodystrophies are not specific to diagnosis and most leukodystrophies remain undiagnosed; however, a logical algorithm based on prevalence could aid the laboratory testing. Because early detection and diagnosis is crucial for treatment and prognosis, it is important to have a high index of suspicion and watchful screening of familial history.
Adrenoleukodystrophy ; Bone Marrow Transplantation ; Canavan Disease ; European Continental Ancestry Group ; Gait ; Hearing Loss ; Humans ; Hyperpigmentation ; Leukodystrophy, Globoid Cell ; Leukodystrophy, Metachromatic ; Logic ; Mass Screening ; Medical Records ; Muscle Hypotonia ; Myelin Sheath ; Paresis ; Pelizaeus-Merzbacher Disease ; Prevalence ; Prognosis ; Retrospective Studies ; Seizures

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.
Brain/*pathology ; Child, Preschool ; Chromosome Mapping ; Chromosomes, Human, X ; Developmental Disabilities/diagnosis/genetics ; Exons ; Gene Duplication ; Humans ; Korea ; Magnetic Resonance Imaging/methods ; Mutation ; Myelin Proteolipid Protein/genetics ; Myelin Sheath/chemistry ; Pelizaeus-Merzbacher Disease/*diagnosis/*genetics ; Polymerase Chain Reaction/*methods

Pelizaeus-Merzbacher disease(PMD) is very rare x-liked recessive leukodystrophy, rather dysmyelinating d due to defect of biosynthesis of proteolipid protein, a component of myelin. Its usual clinical features are stridor, pendular nystagmus, extrapyramidal sign, pyramydal sign, developmental delay and cognition deterioration. Until now PMD has not been published in our country. A 4-year 3 month-old boy developed abnormal eye movement at 3 months of age. His psychomotor development was delayed. On our examination, definite horizontal pendular nystagmus was noted. He showed severe dysarthria, quadriparesis with generalized hyperreflexia, bilateral extensor plantar signs. All laboratory findings including cerebrospinal fluid study were normal. Brain magnetic resonance image (MRI) -revealed diffuse and symmetrical white matter changes in cerebrum and cerebellum. His 23-year-old younger maternal uncle also showed similar clinical history and brain MRI findings. Although the diagnosis of PMD depended on histopathologic investigation, recently MRI can make an important contribution to the diagnosis of PMD with characteristic clinical features. So we could diagnose him and his uncle as PMD.
Brain ; Cerebellum ; Cerebrospinal Fluid ; Cerebrum ; Cognition ; Diagnosis ; Dysarthria ; Eye Movements ; Humans ; Infant ; Magnetic Resonance Imaging* ; Male ; Myelin Sheath ; Nystagmus, Pathologic ; Pelizaeus-Merzbacher Disease* ; Quadriplegia ; Reflex, Abnormal ; Respiratory Sounds ; Young Adult

Pelizaeus-Merzbacher disease (PMD) is a progressive and degenerative chromosomal disorder of the central nervous system caused by defective myelin production. Few case reports have been issued on the anesthetic management of PMD, because of its extremely low incidence. We anesthetized a 13-year-old female patient diagnosed with PMD for ophthalmic surgery because of intermittent exotropia. General anesthesia was induced and maintained with propofol and sevoflurane in air and oxygen. Rocuronium was administered to facilitate orotracheal intubation, and residual neuromuscular blockage was reversed with pyridostigmine. Between emergence to 24 hours postoperatively, her muscle power completely recovered and no unpredictable events occurred. Summarizing, anesthesiologists should be concerned about the high possibility of aspiration, spasticity, and seizure during the perioperative period in patients with even mild PMD. Appropriate preoperative evaluation, intraoperative monitoring, and choice of proper anesthetic drugs enable safe anesthesia in patients with PMD.
Adolescent* ; Anesthesia ; Anesthesia, General* ; Anesthetics ; Central Nervous System ; Chromosome Disorders ; Exotropia ; Female ; Humans ; Incidence ; Intubation ; Monitoring, Intraoperative ; Muscle Spasticity ; Myelin Sheath ; Oxygen ; Pelizaeus-Merzbacher Disease* ; Perioperative Period ; Propofol ; Pyridostigmine Bromide ; Seizures

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder characterized by dysmyelination of the central nervous system (CNS) caused by mutations in the proteolipid protein (PLP) gene. PLP is located at Xq22 and its mutation result in abnormal expression or production of PLP, the most abundant protein in CNS myelin. We present a case of PMD in the 7-year-old boy with nystagmus, ataxia, spastic quadriplegia and severe psychomotor delay. His brain MRI revealed totally dysmyelinated white matter involving entire supratentorial region, atrophic change, and overaccumulation of the iron in both basal ganglia. He also showed soft-tissue contractures of the hip adductors, associated hip dislocations and equinovarus foot deformities due to severe spasticity of lower extremities. Orthopaedic surgery was performed on both hips. Antispastic medication and physical therapy were maintained for reduction of spasticity. We report this case with the review of literatures.
Ataxia ; Basal Ganglia ; Brain ; Central Nervous System ; Child ; Clubfoot ; Contracture ; Foot Deformities ; Hip ; Hip Dislocation ; Humans ; Iron ; Lower Extremity ; Magnetic Resonance Imaging ; Male ; Muscle Spasticity ; Myelin Sheath ; Pelizaeus-Merzbacher Disease* ; Quadriplegia