PMD (Pelizaeus-Merzbacher disease)
An X-linked disorder of the central nervous system (CNS) in which there is loss of myelin (the sheath around the nerve protecting it). PMD affects boys and is characterized by nystagmus (rhythmical oscillation of the eyeballs), psychomotor developmental delay, tremor, spasticity (increased muscular tone), and ataxia (wobbliness). PMD is due to mutations in the gene encoding proteolipid protein (PLP), the most abundant protein of the myelin sheath in the CNS. The mutations result in the loss of myelin that translates into the neurological problems. The severity of myelin loss is dependent on the particular PLP mutation and can range from early lethal forms of PMD to a mild disorder known as spastic paraplegia type 2 (SPG2). Among the mutation in the PLP gene locus that can cause PMD is a duplication of PLP in which the duplicated region may be far away from the original PLP locus in chromosome region Xq22. The PLP duplication is almost always present in the mothers of affected boys and usually can be traced to the maternal grandfather. The disease is named for Friedrich Pelizaeus and Ludwig Merzbacher who independently described it in 1885 and 1909, respectively.

Medical dictionary. 2011.

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  • Pelizaeus-Merzbacher disease — Infobox Disease Name = PAGENAME Caption = DiseasesDB = 29467 ICD10 = ICD10|E|75|2|e|70 ICD9 = ICD9|330.0 ICDO = OMIM = 312080 MedlinePlus = eMedicineSubj = neuro eMedicineTopic = 520 MeshID = D020371Pelizaeus Merzbacher disease (PMD) is a rare… …   Wikipedia

  • Pelizaeus-Merzbacher disease (PMD) — An X linked disorder of the central nervous system (CNS) in which there is loss of myelin (the sheath around the nerve protecting it). PMD affects boys and is characterized by nystagmus (rhythmical oscillation of the eyeballs), psychomotor… …   Medical dictionary

  • Disease, Pelizaeus-Merzbacher (PMD) — An X linked disorder of the central nervous system (CNS) in which there is loss of myelin (the sheath around the nerve protecting it). PMD affects boys and is characterized by nystagmus (rhythmical oscillation of the eyeballs), psychomotor… …   Medical dictionary

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  • Ludwig Merzbacher — (February 9, 1875 October 30, 1942) was a German neuropathologist and psychiatrist who was born in Florence, Italy.In 1900 he received his medical doctorate from the University of Strassburg, and remained in Strassburg as an assistant at the… …   Wikipedia

  • PLP (proteolipid protein) — The most abundant protein of the myelin sheath (the covering of the nerves) in the central nervous system (CNS). The gene that codes for PLP is on the X chromosome. Mutations in PLP cause Pelizaeus Merzbacher disease (PMD), an X linked recessive… …   Medical dictionary

  • Protein, proteolipid (PLP) — The most abundant protein of the myelin sheath (the covering of the nerves) in the central nervous system (CNS). The gene that codes for PLP is on the X chromosome. Mutations in PLP cause Pelizaeus Merzbacher disease (PMD), an X linked recessive… …   Medical dictionary

  • Proteolipid protein (PLP) — The most abundant protein of the myelin sheath (the covering of the nerves) in the central nervous system (CNS). The gene that codes for PLP is on the X chromosome. Mutations in PLP cause Pelizaeus Merzbacher disease (PMD), an X linked recessive… …   Medical dictionary

  • Adrenoleukodystrophy — Classification and external resources T2 weighted axial scan at the level of the caudate heads demonstrates marked loss of posterior white matter, with reduced volume and increased signal intensity. The anterior white matter is spared. Features… …   Wikipedia

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