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Pelizaeus-Merzbacher Disease

PMD


Presentation

  • The very mild presentation in the present case seems to be derived from the unique nature of the mutation, which preserves DM20 production and decreases mutant PLP1.[ncbi.nlm.nih.gov]
  • Amongst the molecularly confirmed patients, 13 presented classical PMD forms but clinical phenotypes varied in the severity even amongst siblings. One patient presented a severe connatal form.[ncbi.nlm.nih.gov]
  • We describe here a very mild case of PMD in a patient who presented with nystagmus in early infancy and was unable to walk until 1 year 7 months of age.[ncbi.nlm.nih.gov]
  • At present, all three patients are living with their families. We report their present hearing, speech and language abilities.[ncbi.nlm.nih.gov]
  • The two male probands presented with severe PMD phenotype and intellectual disability.[ncbi.nlm.nih.gov]
Cerebral Palsy
  • We describe a classical PMD patient who had been misdiagnosed as cerebral palsy. He had nystagmus and psychomotor delay since infancy and tremor with ataxia developing gradually.[ncbi.nlm.nih.gov]
  • The onset is most often in the pediatric age group and may be diagnosed as cerebral palsy because of the subtle onset.[ncbi.nlm.nih.gov]
  • Symptomatic patients included a 6-year-old girl, her younger brother, and their maternal uncle, a 29-year-old college graduate initially diagnosed with cerebral palsy; their brain magnetic resonance imaging studies showed diffuse dysmyelination.[ncbi.nlm.nih.gov]
  • 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.[ncbi.nlm.nih.gov]
  • Pelizaeus-Merzbacher disease was most frequently misdiagnosed as cerebral palsy.[ncbi.nlm.nih.gov]
Pediatric Disorder
  • The thoroughly updated Fourth Edition of this acclaimed reference describes and illustrates the full range of pediatric disorders diagnosable by modern neuroimaging.[books.google.com]
Unable to Stand
  • He subsequently became unable to stand at 15 years old and exhibited mental regression and generalized tonic convulsions by age 20.[ncbi.nlm.nih.gov]
Pharyngitis
  • General anesthesia for a patient with PMD may be difficult mainly because of seizures and airway complications related to poor pharyngeal muscle control. In addition, the possibility of exacerbation of spasticity should be considered.[ncbi.nlm.nih.gov]
  • […] weakness: the pharynx is the voice box; pharyngeal weakness therefore results in speech difficulties Seizures Impaired cognition Lack of development of speech Classic PMD Early symptoms include muscle weakness, involuntary movements of the eye, and delay[ulf.org]
Normal Hearing
  • One of them had a normal hearing threshold in pure-tone audiometry and a normal speech discrimination rate in speech audiometry.[ncbi.nlm.nih.gov]
Muscle Hypotonia
  • The difficulties with movement can include spasticity (stiff or rigid muscles), hypotonia (floppiness), choreoathetosis (extra movements) and ataxia (unsteadiness/loss of coordination).[contact.org.uk]
  • One of the main indicators is abnormal movement of the eyes (horizontal nystagmus), neurological signs of ataxia or various choreoathetotic movements, disruption of mental development, significant muscle hypotonia appears alongside and apart from neurological[kattivatrends.com]
Psychomotor Retardation
  • Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder with severe psychomotor retardation and neurological symptoms due to an inborn abnormality of proteolipid protein (PLP), the major protein component of myelin.[ncbi.nlm.nih.gov]
  • The typical clinical manifestations of PMD include psychomotor retardation, nystagmus, abnormal muscle tone, seizures, and cognitive impairment.[ncbi.nlm.nih.gov]
  • Diffuse hypotonia, nystagmus, psychomotor retardation, visual and hearing impairment have been observed in the patient since the age of 6 weeks.[ncbi.nlm.nih.gov]
  • retardation, involuntary movements, ataxia, and death in the second decade of life.[icd9data.com]
  • Patients with the more common infantile form of AD present in the first 2 years of life with psychomotor retardation, megalencephaly , spasticity and seizures.[neuropathology-web.org]
Neonate-Onset
  • An infant female had connatal Pelizaeus-Merzbacher disease with neonatal onset of developmental failure, seizures, nystagmus, visual impairment, abnormal movements, and spasticity.[ncbi.nlm.nih.gov]
Nystagmus
  • The former had spontaneous vertical pendular nystagmus. He also showed horizontal "micronystagmus", present only at the age of 1 year, which might be similar to "voluntary nystagmus".[ncbi.nlm.nih.gov]
  • Magnetic search-coil oculography of three brothers with clinically diagnosed Pelizaeus-Merzbacher disease disclosed the presence of binocular elliptical pendular nystagmus in two patients in whom the waveform of the nystagmus was not obvious on inspection[ncbi.nlm.nih.gov]
  • Clinical manifestations of PMD are variable and major features include progressive nystagmus, spasticity, tremor, ataxia, and psychomotor delay. We describe a classical PMD patient who had been misdiagnosed as cerebral palsy.[ncbi.nlm.nih.gov]
  • Diffuse hypotonia, nystagmus, psychomotor retardation, visual and hearing impairment have been observed in the patient since the age of 6 weeks.[ncbi.nlm.nih.gov]
  • There is nystagmus and weakness, followed by development of ataxia, cognitive delay and spasticity.[patient.info]
Spastic Paraplegia
  • The disease spectrum for Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is extraordinarily broad, ranging from a spastic gait in the pure form of spastic paraplegia type 2 to a severely disabling form of Pelizaeus-Merzbacher disease featuring[ncbi.nlm.nih.gov]
  • PURPOSE: Pelizaeus-Merzbacher disease and spastic paraplegia type 2 are allelic X-linked disorders that principally affect males and are caused by mutations in the proteolipid protein 1 gene.[ncbi.nlm.nih.gov]
  • KEYWORDS: MAG; Pelizaeus-Merzbacher-like disease; hereditary spastic paraplegia[ncbi.nlm.nih.gov]
  • PLP gene mutations are responsible for a broad spectrum of disease, from the most severe form, connatal PMD, to a less severe form, spastic paraplegia 2 (SPG2).[ncbi.nlm.nih.gov]
Ataxia
  • Ataxia is evident once voluntary movements are acquired and affects virtually all patients. In milder cases, the ataxia affects their speech.[patient.info]
  • Clinical manifestations of PMD are variable and major features include progressive nystagmus, spasticity, tremor, ataxia, and psychomotor delay. We describe a classical PMD patient who had been misdiagnosed as cerebral palsy.[ncbi.nlm.nih.gov]
  • English Pelizaeus-Merzbacher disease hypomyelinating leukodystrophy characterized by impaired myelin formation, nystagmus, spastic quadriplegia, ataxia, and developmental delay that has material basis in mutation in the PLP1 gene on chromosome Xq22 Leukodystrophy[wikidata.org]
  • It is characterized by progressive psychomotor delay, nystagmus, spastic quadriplegia, and cerebellar ataxia. Variable clinical expression was seen in 5 members of a family bearing a novel missense mutation in proteolipid protein 1, c.619T C.[ncbi.nlm.nih.gov]
  • We here present a Korean boy with spastic quadriplegia, horizontal nystagmus, saccadic gaze, intentional tremor, head titubation, ataxia, and developmental delay.[ncbi.nlm.nih.gov]
Tremor
  • Clinical manifestations of PMD are variable and major features include progressive nystagmus, spasticity, tremor, ataxia, and psychomotor delay. We describe a classical PMD patient who had been misdiagnosed as cerebral palsy.[ncbi.nlm.nih.gov]
  • Abstract The paralytic tremor (pt) disease in rabbits results from a point mutation in a plp gene and manifests itself by a broad range of neurological signs.[ncbi.nlm.nih.gov]
  • It differs from this and both the classical and connatal forms of PMD in that it is relatively mild in form, onset is delayed beyond age 2 years, nystagmus is absent, tremors are prominent, mental retardation is not severe, some patients show dementia[ncbi.nlm.nih.gov]
  • We here present a Korean boy with spastic quadriplegia, horizontal nystagmus, saccadic gaze, intentional tremor, head titubation, ataxia, and developmental delay.[ncbi.nlm.nih.gov]
  • Both patients had a late onset (at the ages of 29 and 42 years) and chronic neurological symptoms including tremor, ataxia and dementia.[ncbi.nlm.nih.gov]
Dysarthria
  • Pelizaeus-Merzbacher disease (PMD) is a rare dysmyelination disorder, characterized by significant developmental delay, truncal hypotonia, spasticity, dysarthria, and nystagmus.[ncbi.nlm.nih.gov]
  • We present a case of a male patient affected by the classic form of PMD with benign course, except severe dysarthria with the characteristic laryngeal stridor, which is more typical for connatal form of the disease.[ncbi.nlm.nih.gov]
  • The digitalis therapy induced slight improvement of severe dysarthria and cognitive dysfunction in the two older patients.[ncbi.nlm.nih.gov]
  • We describe three siblings of a consanguineous family manifesting the typical infantile-onset Pelizaeus-Merzbacher disease-like phenotype slowly evolving into a form of complicated hereditary spastic paraplegia with mental retardation, dysarthria, optic[ncbi.nlm.nih.gov]
  • It is marked by nystagmus, ataxia, tremor, choreoathetoid movements, parkinsonian facies, dysarthria, and mental deterioration.[medical-dictionary.thefreedictionary.com]

Treatment

  • It is suggested that patients with PMD may respond to symptomatic treatment modulating nerve conduction.[ncbi.nlm.nih.gov]
  • There is no definitive curative treatment.[ncbi.nlm.nih.gov]
  • This review describes PMD pathology and establishment of new clinical treatment for PMD.[ncbi.nlm.nih.gov]
  • The continuing definition of pathogenetic mechanisms operative in Pelizaeus-Merzbacher disease and spastic paraplegia type 2, together with advances in neural cell transplant therapy, augurs well for future treatment of the severe forms of Pelizaeus-Merzbacher[ncbi.nlm.nih.gov]
  • The variability of clinical manifestations of X-linked epilepsy may be attributed to several factors including the causal genetic mutation, making diagnosis, genetic counseling and treatment decisions difficult.[ncbi.nlm.nih.gov]

Prognosis

  • When combined with suggestive clinical signs, these abnormalities confirm the diagnosis of Pelizaeus-Merzbacher disease, even in the absence of a familial history, and make it possible to warn the parents of the poor prognosis and the risk of recurrence[ncbi.nlm.nih.gov]
  • This study suggested us the difficulty of clinical diagnosis for H-ABC early in the life of the patient, which makes predication of prognosis and genetic counseling difficult.[ncbi.nlm.nih.gov]
  • SPG2 - these patients tend to have a normal lifespan. [ 6 ] There may appear to be periods of stability but the prognosis is for gradual deterioration.[patient.info]
  • Additional symptoms of PMD may include: Slow growth Tremor Failure to develop normal control of head movement Deteriorating speech and mental function The prognosis for those with the severe forms of Pelizaeus-Merzbacher disease is poor, with progressive[inman.moneomed.com]

Etiology

  • These findings suggested defective myelin synthesis as the etiology of Pelizaeus-Merzbacher disease; comprehensive classifications of the disease are expected to include both pathologic and biochemical parameters.[ncbi.nlm.nih.gov]
  • Its genetic etiology can be either a duplication (or other gene dosage alterations) or a punctual mutation at the PLP1 locus.[ncbi.nlm.nih.gov]
  • Collectively, these data provide insights into the pathogeneses of a variety of PLP1 mutations and suggest that disparate etiologies of PMD could require specific treatment approaches for subsets of individuals.[ncbi.nlm.nih.gov]
  • Etiology PMD is an X-linked disorder due to mutations or dosage alterations of the PLP1 gene (Xq22) that cause hypomyelination of the central nervous system (CNS). PMD is allelic to SPG2 which is also due to PLP1 mutations.[orpha.net]

Epidemiology

  • Summary Epidemiology The estimated prevalence is 1/400,000. PMD affects males but some female heterozygotes presenting with a milder phenotype have also been reported (PMD in female carriers; see this term).[orpha.net]
  • Epidemiology [ 6 ] This is a rare disease with an international incidence that is probably between 0.1 and 1 per 100,000 of the population.[patient.info]
Sex distribution
Age distribution

Pathophysiology

  • Although our MR findings correlate well with the pathophysiology of PMD, the MR characteristics are not specific. The diagnosis of PMD remains one of clinical and laboratory exclusion.[ncbi.nlm.nih.gov]
  • Proton MRS imaging may be helpful in evaluating regional pathophysiologic abnormalities in PMD and in distinguishing PMD from other leukodystrophies, which exhibit different metabolic profiles.[ncbi.nlm.nih.gov]
  • Although our MR findings correlate well with the pathophysiology of PMD, the MR characteristics are not specific. The diagnosis of PMD remains one of clinical and laboratory exclusion. Lippincott-Raven Publishers. Related Articles[journals.lww.com]

Prevention

  • Mutations that prevent any PLP1 from being made result in a syndrome (PLP1 null syndrome) that is usually milder than classic Pelizaeus-Merzbacher disease.[emedicine.com]
  • Preventive intervention is required to avoid catastrophic TIF due to its high mortality rate.[ncbi.nlm.nih.gov]
  • […] includes medications for seizures and spasticity; physical therapy, exercise, and orthotics for spasticity management; surgery for contractures and scoliosis; gastrostomy for severe dysphagia; proper wheelchair seating, physical therapy, and orthotics to prevent[ncbi.nlm.nih.gov]
  • Proteasome inhibition (MG132) prevented the enhanced degradation. Numerous autophagic vesicles are present in homozygous transgenic mice that may influence protein dynamics.[ncbi.nlm.nih.gov]

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