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| {{Orphan|date=February 2017}} | | {{Short description|A rare neurological disorder characterized by involuntary movements on one side of the body mirroring voluntary movements on the opposite side.}} |
| {{Infobox medical condition (new) | | {{Infobox medical condition (new) |
| | name = Congenital mirror movement disorder | | | name = Congenital mirror movement disorder |
| | synonyms = | | | synonyms = CMM disorder |
| | image = Autosomal dominant - en.svg | | | image = Autosomal dominant - en.svg |
| | alt = | | | alt = |
| | caption = This condition is inherited via autosomal dominant manner | | | caption = This condition is inherited via autosomal dominant manner |
| | pronounce = | | | pronounce = |
| | field = | | | field = [[Neurology]], [[Medical genetics]] |
| | symptoms = | | | symptoms = Involuntary mirroring of intentional movements on the opposite side of the body (typically hands) |
| | complications = | | | complications = Motor coordination difficulties, functional limitations in daily tasks |
| | onset = | | | onset = Birth or early infancy |
| | duration = | | | duration = Lifelong |
| | types = | | | types = Isolated (nonsyndromic) or syndromic forms |
| | causes = | | | causes = Mutations in the [[DACT1]], [[RAD51]], or [[DNAL4]] genes; disruption in corticospinal tract development |
| | risks = | | | risks = Family history of CMM; autosomal dominant inheritance pattern |
| | diagnosis = | | | diagnosis = Clinical examination, [[electromyography]] (EMG), [[genetic testing]] |
| | differential = | | | differential = [[Parkinson's disease]], [[Klippel–Feil syndrome]], [[Moebius syndrome]] |
| | prevention = | | | prevention = None |
| | treatment = | | | treatment = Supportive care, [[occupational therapy]], [[physical therapy]] |
| | medication = | | | medication = None specific; [[botulinum toxin]] in some cases |
| | prognosis = | | | prognosis = Typically stable; symptoms may improve with therapy but usually persist |
| | frequency = | | | frequency = Rare |
| | deaths = | | | deaths = Not life-threatening |
| }} | | }} |
| '''Congenital mirror movement disorder''' '''(CMM disorder)''' is a [[Rare disease|rare]] [[Genetic disorder|genetic]] [[neurological disorder]] which is characterized by mirrored movement, sometimes referred to as associated or synkinetic movement, most often in the upper extremity of the body.<ref name=":05">{{Cite web|url=https://ghr.nlm.nih.gov/condition/congenital-mirror-movement-disorder|title=congenital mirror movement disorder|last=Reference|first=Genetics Home|website=Genetics Home Reference|language=en|access-date=2017-12-06}}</ref><ref name=":18">{{Cite book|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK279760/|title=GeneReviews®|last=Méneret|first=Aurélie|last2=Trouillard|first2=Oriane|last3=Depienne|first3=Christel|last4=Roze|first4=Emmanuel|date=1993|publisher=University of Washington, Seattle|editor-last=Adam|editor-first=Margaret P.|location=Seattle (WA)|pmid=25763452|editor-last2=Ardinger|editor-first2=Holly H.|editor-last3=Pagon|editor-first3=Roberta A.|editor-last4=Wallace|editor-first4=Stephanie E.|editor-last5=Bean|editor-first5=Lora JH|editor-last6=Mefford|editor-first6=Heather C.|editor-last7=Stephens|editor-first7=Karen|editor-last8=Amemiya|editor-first8=Anne|editor-last9=Ledbetter|editor-first9=Nikki|chapter=Congenital Mirror Movements}}</ref> These movements are voluntary intentional movements on one, [[Anatomical terms of location|ipsilateral]], side of the body that are mirrored simultaneously by involuntary movements on the [[Anatomical terms of location|contralateral]] side.<ref name=":83">{{Cite journal|last=Galléa|first=Cécile|last2=Popa|first2=Traian|last3=Billot|first3=Ségolène|last4=Méneret|first4=Aurélie|last5=Depienne|first5=Christel|last6=Roze|first6=Emmanuel|date=November 2011|title=Congenital mirror movements: a clue to understanding bimanual motor control|journal=Journal of Neurology|volume=258|issue=11|pages=1911–1919|doi=10.1007/s00415-011-6107-9|issn=1432-1459|pmid=21633904}}</ref> | | '''Congenital mirror movement disorder''' (CMM) is a rare [[neurological disorder]] characterized by involuntary movements on one side of the body that mirror voluntary movements on the opposite side. This condition is present from birth and is typically noticed in early childhood. |
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| The reproduction of involuntary movement usually happens along the head-tail axis, having a left-right [[Symmetry in biology|symmetry]].<ref name=":05"/> For example, if someone were to voluntarily make a fist with their left hand, their right hand would do the same. In most cases, the accompanying contralateral involuntary movements are much weaker than the ipsilateral voluntary ones, although the extent and magnitude of the mirrored movement vary across patients.<ref name=":33">{{Cite journal|last=Schott|first=G D|last2=Wyke|first2=M A|date=July 1981|title=Congenital mirror movements.|pmc=491063|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=44|issue=7|pages=586–599|issn=0022-3050|pmid=7288446|doi=10.1136/jnnp.44.7.586}}</ref> This disorder has not yet been found to be associated with any other [[Neurological disorder|neurologic disease]] or [[cognitive disability]], and currently, no cures nor means to improve signs or symptoms have been found.<ref name=":18"/><ref name=":43">{{Cite web|url=https://rarediseases.info.nih.gov/diseases/12551/congenital-mirror-movement-disorder|title=Congenital mirror movement disorder {{!}} Genetic and Rare Diseases Information Center (GARD) – an NCATS Program|website=rarediseases.info.nih.gov|language=en|access-date=2017-12-06}}</ref>
| | ==Presentation== |
| | Individuals with congenital mirror movement disorder exhibit involuntary movements that occur simultaneously with intentional movements on the opposite side of the body. For example, when a person with CMM moves their right hand, their left hand may involuntarily perform the same movement. These mirror movements are most commonly observed in the [[upper limbs]], particularly the hands and fingers, but can also affect the [[lower limbs]]. |
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| The congenital mirror movements begin in [[Infant|infancy]] and persist throughout the patient’s life, often with very little improvement, or deterioration.<ref name=":83"/> Consequently, patients who do suffer from this movement disorder have serious difficulty carrying out tasks that require manual dexterity or precision, such as playing a two handed musical instrument or typing on a keyboard, for their whole lives.<ref name=":33"/><ref name=":54">{{Cite journal|last=Méneret|first=Aurélie|last2=Depienne|first2=Christel|last3=Riant|first3=Florence|last4=Trouillard|first4=Oriane|last5=Bouteiller|first5=Delphine|last6=Cincotta|first6=Massimo|last7=Bitoun|first7=Pierre|last8=Wickert|first8=Julia|last9=Lagroua|first9=Isabelle|date=2014-06-03|title=Congenital mirror movements|journal=Neurology|volume=82|issue=22|pages=1999–2002|doi=10.1212/WNL.0000000000000477|issn=0028-3878|pmc=4105259|pmid=24808016}}</ref> Patients also often experience discomfort or [[pain]] in the upper limbs due to prolonged use of the same muscles. Therefore, quality of life can be severely hampered.<ref name=":83"/> | | ==Pathophysiology== |
| | The exact cause of congenital mirror movement disorder is not fully understood, but it is believed to involve abnormal development of the [[nervous system]]. In typical development, the [[motor cortex]] in the brain controls movements on the opposite side of the body. In individuals with CMM, there may be abnormal connections or lack of proper inhibition between the two hemispheres of the brain, leading to simultaneous activation of both sides. |
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| CMM disorder’s prevalence in the world is thought to be less than 1 in 1 million people.<ref name=":05"/><ref name=":43"/> Because of its rarity, researchers suggest that some mildly affected individuals may never be diagnosed.<ref name=":18"/><ref name=":54"/> It is important not to confuse congenital mirror movement disorders, a rare genetically based neurologic disease, with [[Acquired brain injury|acquired]] mirror movement disorders that present themselves during one’s lifetime due to other reasons (stroke for example).<ref name=":18"/>
| | ==Genetics== |
| | Congenital mirror movement disorder can be inherited in an [[autosomal dominant]] pattern, meaning a single copy of the altered gene in each cell is sufficient to cause the disorder. Mutations in the [[DCC gene]] have been associated with CMM. The DCC gene is involved in the development of the nervous system, particularly in the guidance of [[neurons]] and the formation of [[neural circuits]]. |
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| == Causes == | | ==Diagnosis== |
| The specific [[Molecular biology|molecular mechanism]] that underpins this [[Movement disorders|movement disorder]] is not well known.<ref name=":18"/> However, most researchers suggest that it follows an [[Dominance (genetics)|autosomal dominant]] genetic [[Heredity|inheritance pattern]] in which [[mutation]]s in certain [[gene]]s give rise to structural abnormalities in [[nervous system]] networks responsible for voluntary [[Skeletal muscle|skeletal muscle movement]], which, in turn, result in the functional movement abnormalities seen in patients.<ref name=":05"/><ref name=":18"/><ref name=":92">{{Cite journal|last=Depienne|first=Christel|last2=Bouteiller|first2=Delphine|last3=Méneret|first3=Aurélie|last4=Billot|first4=Ségolène|last5=Groppa|first5=Sergiu|last6=Klebe|first6=Stephan|last7=Charbonnier-Beaupel|first7=Fanny|last8=Corvol|first8=Jean-Christophe|last9=Saraiva|first9=Jean-Paul|date=2012-02-10|title=RAD51 haploinsufficiency causes congenital mirror movements in humans|journal=American Journal of Human Genetics|volume=90|issue=2|pages=301–307|doi=10.1016/j.ajhg.2011.12.002|issn=1537-6605|pmc=3276668|pmid=22305526}}</ref><ref name=":7">{{Cite journal|last=Ahmed|first=Iltaf|last2=Mittal|first2=Kirti|last3=Sheikh|first3=Taimoor I.|last4=Vasli|first4=Nasim|last5=Rafiq|first5=Muhammad Arshad|last6=Mikhailov|first6=Anna|last7=Ohadi|first7=Mehrnaz|last8=Mahmood|first8=Huda|last9=Rouleau|first9=Guy A.|date=November 2014|title=Identification of a homozygous splice site mutation in the dynein axonemal light chain 4 gene on 22q13.1 in a large consanguineous family from Pakistan with congenital mirror movement disorder|journal=Human Genetics|volume=133|issue=11|pages=1419–1429|doi=10.1007/s00439-014-1475-8|issn=1432-1203|pmid=25098561}}</ref><ref name=":6">{{Cite journal|last=Méneret|first=Aurélie|last2=Franz|first2=Elizabeth A.|last3=Trouillard|first3=Oriane|last4=Oliver|first4=Thomas C.|last5=Zagar|first5=Yvrick|last6=Robertson|first6=Stephen P.|last7=Welniarz|first7=Quentin|last8=Gardner|first8=R. J. MacKinlay|last9=Gallea|first9=Cécile|date=2017-11-01|title=Mutations in the netrin-1 gene cause congenital mirror movements|journal=The Journal of Clinical Investigation|volume=127|issue=11|pages=3923–3936|doi=10.1172/JCI95442|issn=1558-8238|pmid=28945198|pmc=5663368}}</ref> Despite being autosomal dominant, it is important to note that the disease has [[Penetrance|variable expressivity]].<ref name=":83"/> That is, patients who have inherited a mutated dominant allele, along with their genetically affected parent, can be [[symptom]]atic or asymptomatic for CMM disorder.<ref name=":33"/> The genes that currently have evidence to be associated with CMM disorder include ''[[DCC1|DCC]]'' (deleted in colorectal carcinoma), ''[[DNAL4]]'' (dynein axonemal light chain 4), and ''[[RAD51]] (recombination protein A)''.<ref name=":54"/><ref name=":112">{{Cite journal|last=Franz|first=Elizabeth A.|last2=Chiaroni-Clarke|first2=Rachel|last3=Woodrow|first3=Stephanie|last4=Glendining|first4=Kelly A.|last5=Jasoni|first5=Christine L.|last6=Robertson|first6=Stephen P.|last7=Gardner|first7=R. J. McKinlay|last8=Markie|first8=David|date=2015-04-15|title=Congenital mirror movements: phenotypes associated with DCC and RAD51 mutations|journal=Journal of the Neurological Sciences|volume=351|issue=1–2|pages=140–145|doi=10.1016/j.jns.2015.03.006|issn=1878-5883|pmid=25813273}}</ref>
| | Diagnosis of congenital mirror movement disorder is primarily clinical, based on the observation of mirror movements. [[Neurological examination]] and [[electromyography]] (EMG) may be used to assess the extent and nature of the movements. Genetic testing can confirm the presence of mutations associated with the disorder. |
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| ''DCC'' encodes a [[Receptor (biochemistry)|receptor]] for ''[[Netrin 1|NTN1]]'' (netrin-1), a [[protein]] thought to be responsible for [[axon guidance]] and neuronal [[cell migration]] during [[Developmental biology|development]].<ref name=":142">{{Cite journal|last=Depienne|first=C.|last2=Cincotta|first2=M.|last3=Billot|first3=S.|last4=Bouteiller|first4=D.|last5=Groppa|first5=S.|last6=Brochard|first6=V.|last7=Flamand|first7=C.|last8=Hubsch|first8=C.|last9=Meunier|first9=S.|date=2011-01-18|title=A novel DCC mutation and genetic heterogeneity in congenital mirror movements|journal=Neurology|volume=76|issue=3|pages=260–264|doi=10.1212/WNL.0b013e318207b1e0|issn=1526-632X|pmid=21242494}}</ref><ref>{{Cite journal|last=Djarmati-Westenberger|first=A.|last2=Brüggemann|first2=N.|last3=Espay|first3=A. J.|last4=Bhatia|first4=K. P.|last5=Klein|first5=C.|date=2011-10-18|title=A novel DCC mutation and genetic heterogeneity in congenital mirror movements|journal=Neurology|volume=77|issue=16|pages=1580|doi=10.1212/WNL.0b013e318230b140|issn=1526-632X|pmid=22006891}}</ref> A mutation of this gene (including [[Nonsense mutation|nonsense]], [[splice site mutation]], [[Insertion (genetics)|insertions]], [[Frameshift mutation|frameshift]]) has been identified as a possible cause for CMM disorder.<ref name=":18"/><ref>{{Cite journal|last=Kanouchi|first=T.|last2=Yokota|first2=T.|last3=Isa|first3=F.|last4=Ishii|first4=K.|last5=Senda|first5=M.|date=June 1997|title=Role of the ipsilateral motor cortex in mirror movements|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=62|issue=6|pages=629–632|issn=0022-3050|pmc=1074150|pmid=9219752|doi=10.1136/jnnp.62.6.629}}</ref><ref name=":133">{{Cite journal|last=Srour|first=Myriam|last2=Rivière|first2=Jean-Baptiste|last3=Pham|first3=Jessica M. T.|last4=Dubé|first4=Marie-Pierre|last5=Girard|first5=Simon|last6=Morin|first6=Steves|last7=Dion|first7=Patrick A.|last8=Asselin|first8=Géraldine|last9=Rochefort|first9=Daniel|date=2010-04-30|title=Mutations in DCC cause congenital mirror movements|journal=Science|volume=328|issue=5978|pages=592|doi=10.1126/science.1186463|issn=1095-9203|pmid=20431009}}</ref> Experiments in mice also support the claim that CMM disorder is associated with genetic mutations in ''DCC''.<ref name=":6" /> ''Kanga'' mice, lacking the P3 intracellular domain of the ''DCC'' receptor, show a hopping gait, moving their hind legs in a strictly paired fashion, as do [[kangaroo]]s.<ref name=":83"/><ref>{{Cite web|url=https://www.jax.org/strain/029220|title=029220 - CBy.Cg-Dcc<kanga>/GrsrJ|website=www.jax.org|access-date=2017-12-06}}</ref>
| | ==Management== |
| | There is currently no cure for congenital mirror movement disorder. Management focuses on minimizing the impact of the disorder on daily activities. [[Physical therapy]] and [[occupational therapy]] may help improve motor skills and coordination. In some cases, [[botulinum toxin]] injections have been used to reduce the severity of mirror movements. |
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| ''DNAL4'' encodes a component of [[dynein]] [[Motor neuron|motor complex]] in [[Commissural fiber|commissural neurons]] of the [[corpus callosum]].<ref name=":05"/><ref name=":54"/><ref name=":83"/> In contrast to ''DCC'', ''DNAL4'' is thought to have a [[Dominance (genetics)|recessive]] inheritance pattern for the CMM disorder.<ref name=":7" /> In CMM disorder patients, researchers found splice site mutations on ''DNAL4'', which caused skipping of [[exon]] 3, and thereby omission of 28 [[amino acid]]s from ''DNAL4'' protein.<ref name=":7" /> This mutant ''DNAL4'' protein, in turn, could lead to faulty cross-hemisphere wiring, resulting in CMM.<ref name=":7" /><ref name=":152">{{Cite journal|last=Welniarz|first=Quentin|last2=Morel|first2=Marie-Pierre|last3=Pourchet|first3=Oriane|last4=Gallea|first4=Cécile|last5=Lamy|first5=Jean-Charles|last6=Cincotta|first6=Massimo|last7=Doulazmi|first7=Mohamed|last8=Belle|first8=Morgane|last9=Méneret|first9=Aurélie|date=2017-03-24|title=Non cell-autonomous role of DCC in the guidance of the corticospinal tract at the midline|journal=Scientific Reports|volume=7|issue=1|pages=410|doi=10.1038/s41598-017-00514-z|issn=2045-2322|pmc=5428661|pmid=28341853}}</ref>
| | ==Prognosis== |
| | The prognosis for individuals with congenital mirror movement disorder varies. While the condition is lifelong, many individuals learn to adapt to the involuntary movements and lead normal lives. The severity of the disorder can vary widely among affected individuals. |
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| ''RAD51'' maintains [[genome]] integrity by repairing [[DNA|DNA double-strand]] breaks through [[homologous recombination]].<ref name=":92"/> ''RAD51'' [[Zygosity|heterozygous]] mutations, specifically premature [[Stop codon|termination codons]], have been found in many CMM disorder patients through [[Genome-wide association study|genome-wide linkage analysis]] and [[exome sequencing]].<ref name=":05"/><ref name=":18"/><ref name=":33"/><ref name=":54"/> In a mouse model, researchers also found ''RAD51'' products in [[corticospinal tract]] [[axon]]s at the [[Medullary pyramids (brainstem)|pyramidal decussation]].<ref name=":92"/> They therefore suggest that ''RAD51'' might be a gene that, when haploinsufficient, causes CMM disorder in humans.<ref name=":92"/>
| | ==Related pages== |
| | | * [[Neurological disorder]] |
| Despite identification of three prospective genes, no [[genotype]]-[[phenotype]] correlations have yet been found.<ref name=":05"/><ref name=":18"/> That is, the severity of clinical signs and symptoms does not correlate with the type of genetic variant.<ref name=":83"/><ref name=":102">{{Cite journal|last=Galléa|first=Cécile|last2=Popa|first2=Traian|last3=Billot|first3=Ségolène|last4=Méneret|first4=Aurélie|last5=Depienne|first5=Christel|last6=Roze|first6=Emmanuel|date=2011-11-01|title=Congenital mirror movements: a clue to understanding bimanual motor control|journal=Journal of Neurology|language=en|volume=258|issue=11|pages=1911–1919|doi=10.1007/s00415-011-6107-9|pmid=21633904|issn=0340-5354}}</ref> Mutations in the above genes account for a total of about 35 percent of cases.<ref name=":05"/> Mutations in other genes that have not been identified likely account for the other cases of this disorder.<ref name=":05"/>
| | * [[Motor cortex]] |
| | | * [[Autosomal dominant]] |
| == Pathophysiology ==
| | * [[DCC gene]] |
| There are three main pathophysiological hypotheses for congenital mirror movement disorder that exist.
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| === ''Interhemispheric connections'' ===
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| First, some researchers believe that this neurological disorder is due to abnormal communication between [[cerebral hemisphere]]s.<ref name=":54"/> They explain the mechanism of the physiological miscommunication with on development.<ref name=":162">{{Cite journal|last=Giedd|first=J. N.|last2=Blumenthal|first2=J.|last3=Jeffries|first3=N. O.|last4=Castellanos|first4=F. X.|last5=Liu|first5=H.|last6=Zijdenbos|first6=A.|last7=Paus|first7=T.|last8=Evans|first8=A. C.|last9=Rapoport|first9=J. L.|date=October 1999|title=Brain development during childhood and adolescence: a longitudinal MRI study|journal=Nature Neuroscience|volume=2|issue=10|pages=861–863|doi=10.1038/13158|issn=1097-6256|pmid=10491603}}</ref>
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| Amongst many neuronal changes in the brain during normal human brain development, researchers claim that the [[corpus callosum]] shows a gradual increase number of [[Myelin|myelinated axons]].<ref name=":162" /> This suggests that up until a certain age, the corpus callosum is heavily unmyelinated. This would explain why children during normal development can be seen with CMM disorder up to the age of 7 years, likely due to lack of corpus callosum development.<ref name=":54"/><ref>{{Cite journal|last=Garvey|first=M. A.|last2=Ziemann|first2=U.|last3=Bartko|first3=J. J.|last4=Denckla|first4=M. B.|last5=Barker|first5=C. A.|last6=Wassermann|first6=E. M.|date=September 2003|title=Cortical correlates of neuromotor development in healthy children|journal=Clinical Neurophysiology|volume=114|issue=9|pages=1662–1670|issn=1388-2457|pmid=12948795|doi=10.1016/s1388-2457(03)00130-5}}</ref> The normal disappearance of clinically significant mirror movements after this age is associated with [[Anatomy|anatomical]] and functional maturation of [[Interhemispheric fissure|interhemispheric]] connections through the corpus callosum between [[Motor cortex|motor cortices]].<ref>{{Cite journal|last=Leinsinger|first=G L|last2=Heiss|first2=D T|last3=Jassoy|first3=A G|last4=Pfluger|first4=T|last5=Hahn|first5=K|last6=Danek|first6=A|date=1997-05-01|title=Persistent mirror movements: functional MR imaging of the hand motor cortex.|journal=Radiology|volume=203|issue=2|pages=545–552|doi=10.1148/radiology.203.2.9114119|pmid=9114119|issn=0033-8419}}</ref> Researchers hypothesize that this axonal density in the corpus callosum is responsible for the interhemispheric communication that is ultimately responsible for the suppression of mirror movements during voluntary movements in healthy adults.<ref>{{Cite journal|last=Wahl|first=Mathias|last2=Lauterbach-Soon|first2=Birgit|last3=Hattingen|first3=Elke|last4=Jung|first4=Patrick|last5=Singer|first5=Oliver|last6=Volz|first6=Steffen|last7=Klein|first7=Johannes C.|last8=Steinmetz|first8=Helmuth|last9=Ziemann|first9=Ulf|date=2007-11-07|title=Human motor corpus callosum: topography, somatotopy, and link between microstructure and function|journal=The Journal of Neuroscience|volume=27|issue=45|pages=12132–12138|doi=10.1523/JNEUROSCI.2320-07.2007|issn=1529-2401|pmid=17989279|doi-access=free}}</ref> Therefore, disruptions in corpus callosum circuits could lead to CMM.<ref name=":18"/>
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| === ''Motor cortex '' ===
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| Another pathophysiological explanation that researchers suggest for CMM disorder is that there is a miscommunication during motor movement execution.<ref name=":54"/> This claim is supported by evidence of structural abnormalities in the [[primary motor cortex]] (M1) in CMM patients.<ref name=":05"/><ref name=":18"/><ref name=":33"/><ref name=":83"/> These structural abnormalities in the motor cortex might explain why the hands, requiring great motor [[dexterity]] and therefore have a large cortical representation, are often the target of and suffer from more severe mirror movement in CMM disorder.<ref name=":05"/>
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| === ''Corticospinal tract'' ===
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| A third pathophysiological explanation proposed by researchers has to do with the [[corticospinal tract]] (CST).<ref name=":05"/><ref name=":43"/><ref name=":152"/><ref>{{Cite journal|last=Ueki|first=Y.|last2=Mima|first2=T.|last3=Oga|first3=T.|last4=Ikeda|first4=A.|last5=Hitomi|first5=T.|last6=Fukuyama|first6=H.|last7=Nagamine|first7=T.|last8=Shibasaki|first8=H.|date=February 2005|title=Dominance of ipsilateral corticospinal pathway in congenital mirror movements|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=76|issue=2|pages=276–279|doi=10.1136/jnnp.2004.040949|issn=0022-3050|pmc=1739493|pmid=15654052}}</ref> Healthy newborns in fact have ipsilateral CST projections up until the age of around 7.<ref>{{Cite journal|last=Koerte|first=Inga|last2=Eftimov|first2=Lara|last3=Laubender|first3=Ruediger Paul|last4=Esslinger|first4=Olaf|last5=Schroeder|first5=Andreas Sebastian|last6=Ertl-Wagner|first6=Birgit|last7=Wahllaender-Danek|first7=Ute|last8=Heinen|first8=Florian|last9=Danek|first9=Adrian|date=December 2010|title=Mirror movements in healthy humans across the lifespan: effects of development and ageing|journal=Developmental Medicine and Child Neurology|volume=52|issue=12|pages=1106–1112|doi=10.1111/j.1469-8749.2010.03766.x|issn=1469-8749|pmid=21039436}}</ref> During normal adult development, these axonal projects disappear. This might provide an alternate explanation for the presence of mild mirror movements in normally developing young children that typically disappear before the age of 7.<ref>{{Cite journal|last=Mayston|first=M. J.|last2=Harrison|first2=L. M.|last3=Stephens|first3=J. A.|date=May 1999|title=A neurophysiological study of mirror movements in adults and children|journal=Annals of Neurology|volume=45|issue=5|pages=583–594|issn=0364-5134|pmid=10319880|doi=10.1002/1531-8249(199905)45:5<583::aid-ana6>3.0.co;2-w}}</ref>
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| Some researchers propose that ''DCC'' mutations cause a reduction in [[gene expression]] and less robust [[Midline shift|midline guidance]], which may lead to a partial failure of axonal fiber crossing and encourage development of an abnormal ipsilateral connection.<ref name=":92"/> This is confirmed by other researchers who demonstrate that patients with ''DDC'' mutants show an increased proportion of ipsilateral axonal projections, and show that even a very small number of aberrant ipsilateral descending axons is sufficient to induce incorrect movement patterns.<ref name=":142"/><ref name=":133"/><ref>{{Cite journal|last=Jain|first=Roshan A.|last2=Bell|first2=Hannah|last3=Lim|first3=Amy|last4=Chien|first4=Chi-Bin|last5=Granato|first5=Michael|date=2014-02-19|title=Mirror movement-like defects in startle behavior of zebrafish dcc mutants are caused by aberrant midline guidance of identified descending hindbrain neurons|journal=The Journal of Neuroscience|volume=34|issue=8|pages=2898–2909|doi=10.1523/JNEUROSCI.2420-13.2014|issn=1529-2401|pmc=3931503|pmid=24553931}}</ref>
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| These findings are corroborated by evidence from mice models, ''Kanga'' mice with a deletion of ''DCC'', whose CST has been shown not to be altered'','' but rather partially rerouted ipsilaterally.<ref name=":152" />
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| == Diagnosis ==
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| Currently, clinical diagnosis of CMM disorder has been based on [[clinical trial|clinical findings]] or [[Genetic testing|molecular genetic testing]].<ref name=":18"/>
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| ''Clinical Findings (Signs and Symptoms)''<ref name=":05"/>''<ref name=":18"/><ref name=":112"/>''<ref name=":122">{{Cite journal|last=Meneret|first=Aurelie|last2=Trouillard|first2=Oriane|last3=Brochard|first3=Vanessa|last4=Roze|first4=Emmanuel|date=August 2015|title=Congenital mirror movements caused by a mutation in the DCC gene|journal=Developmental Medicine and Child Neurology|volume=57|issue=8|pages=776|doi=10.1111/dmcn.12810|issn=1469-8749|pmid=26011025}}</ref><ref name=":133"/>'':''
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| * onset of mirror movements in infancy or early childhood
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| * persistence of mirror movements into and throughout adulthood with the absence of other neurologic disorders
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| * little improvement nor deterioration of mirror movements over the course of one’s life
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| * intensity of mirrored movements increasing with the complexity of the voluntary movement
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| * involuntary mirror movements that are generally of lesser amplitude compared with voluntary movements
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| * predominant mirror movement in upper limbs, with increasing severity in more [[Anatomical terms of location|distal]] [[appendage]]s (fingers) | |
| * inability to perform tasks requiring skilled bimanual coordination | |
| * occasional pain in the upper limbs during prolonged manual activities
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| * occasional observed [[subclinical]] mirroring movement, but detectable with [[Accelerometer|accelerometer gloves]]
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| ''Molecular genetic testing''<ref name=":05"/>'':''
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| * identification of a heterozygous mutant ''DCC, DNAL4, or RAD51'' gene ([[Genetic testing|single gene test]] or multi-gene panel)
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| == Treatment and Management ==
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| CMM has clear severe impacts on a patient’s ability to carry out daily [[Manual labour|manual tasks]].<ref>{{Cite journal|last=Cincotta|first=M.|last2=Borgheresi|first2=A.|last3=Boffi|first3=P.|last4=Vigliano|first4=P.|last5=Ragazzoni|first5=A.|last6=Zaccara|first6=G.|last7=Ziemann|first7=U.|date=2002-04-23|title=Bilateral motor cortex output with intended unimanual contraction in congenital mirror movements|journal=Neurology|language=en|volume=58|issue=8|pages=1290–1293|doi=10.1212/WNL.58.8.1290|issn=0028-3878|pmid=11971104}}</ref><ref name=":102"/> It is recommended that children be placed under more forgiving school environments, allowing more time for written evaluations and limiting handwritten assignments, to ease the burden of the movement disability.<ref name=":05"/><ref name=":83"/> Furthermore, because of patients’ inability to perform pure unilateral movements and their difficulty with tasks requiring skilled bimanual coordination, young and new members to the [[workforce]] are encouraged to consider [[profession]]s that do not require complex bimanual movements, repetitive or sustained hand movements, or extensive handwriting, to reduce overuse, pain, and discomfort in upper limbs.<ref name=":18"/><ref name=":43"/>
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| Because of its pronounced and obviously noticeable signs and symptoms, CMM patients can suffer [[social stigma]]; however, physicians need to make it clear to parents, family, and friends that the disorder bears no relation to [[Intellectual disability|intellectual abilities]].<ref name=":43" /><ref>{{Cite journal|last=Rasmussen|first=Peder|date=1993-08-01|title=Persistent Mirror Movements: A Clinical Study of 17 Children, Adolescents and Young Adults|journal=Developmental Medicine & Child Neurology|language=en|volume=35|issue=8|pages=699–707|doi=10.1111/j.1469-8749.1993.tb11715.x|issn=1469-8749}}</ref> However, the rarity of this neurologic disease, found in one in a million people, makes its societal and cultural significance quite limited.<ref name=":54"/>
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| == Related Diseases ==
| |
| * [[Movement disorders]]
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| * [[Chiari malformation]]
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| * [[Klippel–Feil syndrome|Klippel-Feil Syndrome]]
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| * [[Dystonia]]
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| * [[Cerebral palsy]]
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| * [[Parkinson's disease]]
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| * [[Epilepsy|Epilepsies]]
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| * [[Amyotrophic lateral sclerosis]]
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| * [[Kallmann syndrome|Kallman's syndrome]]
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| * [[Alien hand syndrome]]
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| * [[Obsessive–compulsive disorder|Obsessive compulsive disorder]]
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| * [[Schizophrenia]]
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| * [[Congenital hemiplegia]]
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| * [[Möbius syndrome|Moebius syndrome]]
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| * [[Seckel syndrome]]
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| * [[Wildervanck syndrome]]
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| *Polymicrogyria
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| | |
| == References ==
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| {{reflist}}
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|
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| == External links == | | == External links == |
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| | Orphanet = 238722 | | | Orphanet = 238722 |
| }} | | }} |
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| [[Category:Extrapyramidal and movement disorders]] | | [[Category:Extrapyramidal and movement disorders]] |
| {{dictionary-stub1}}
| | [[Category:Neurological disorders]] |
| | [[Category:Genetic disorders]] |
| | [[Category:Movement disorders]] |
A rare neurological disorder characterized by involuntary movements on one side of the body mirroring voluntary movements on the opposite side.
| Congenital mirror movement disorder
|
|
| Synonyms
|
CMM disorder
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| Pronounce
|
|
| Field
|
Neurology, Medical genetics
|
| Symptoms
|
Involuntary mirroring of intentional movements on the opposite side of the body (typically hands)
|
| Complications
|
Motor coordination difficulties, functional limitations in daily tasks
|
| Onset
|
Birth or early infancy
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| Duration
|
Lifelong
|
| Types
|
Isolated (nonsyndromic) or syndromic forms
|
| Causes
|
Mutations in the DACT1, RAD51, or DNAL4 genes; disruption in corticospinal tract development
|
| Risks
|
Family history of CMM; autosomal dominant inheritance pattern
|
| Diagnosis
|
Clinical examination, electromyography (EMG), genetic testing
|
| Differential diagnosis
|
Parkinson's disease, Klippel–Feil syndrome, Moebius syndrome
|
| Prevention
|
None
|
| Treatment
|
Supportive care, occupational therapy, physical therapy
|
| Medication
|
None specific; botulinum toxin in some cases
|
| Prognosis
|
Typically stable; symptoms may improve with therapy but usually persist
|
| Frequency
|
Rare
|
| Deaths
|
Not life-threatening
|
Congenital mirror movement disorder (CMM) is a rare neurological disorder characterized by involuntary movements on one side of the body that mirror voluntary movements on the opposite side. This condition is present from birth and is typically noticed in early childhood.
Presentation[edit]
Individuals with congenital mirror movement disorder exhibit involuntary movements that occur simultaneously with intentional movements on the opposite side of the body. For example, when a person with CMM moves their right hand, their left hand may involuntarily perform the same movement. These mirror movements are most commonly observed in the upper limbs, particularly the hands and fingers, but can also affect the lower limbs.
Pathophysiology[edit]
The exact cause of congenital mirror movement disorder is not fully understood, but it is believed to involve abnormal development of the nervous system. In typical development, the motor cortex in the brain controls movements on the opposite side of the body. In individuals with CMM, there may be abnormal connections or lack of proper inhibition between the two hemispheres of the brain, leading to simultaneous activation of both sides.
Genetics[edit]
Congenital mirror movement disorder can be inherited in an autosomal dominant pattern, meaning a single copy of the altered gene in each cell is sufficient to cause the disorder. Mutations in the DCC gene have been associated with CMM. The DCC gene is involved in the development of the nervous system, particularly in the guidance of neurons and the formation of neural circuits.
Diagnosis[edit]
Diagnosis of congenital mirror movement disorder is primarily clinical, based on the observation of mirror movements. Neurological examination and electromyography (EMG) may be used to assess the extent and nature of the movements. Genetic testing can confirm the presence of mutations associated with the disorder.
Management[edit]
There is currently no cure for congenital mirror movement disorder. Management focuses on minimizing the impact of the disorder on daily activities. Physical therapy and occupational therapy may help improve motor skills and coordination. In some cases, botulinum toxin injections have been used to reduce the severity of mirror movements.
Prognosis[edit]
The prognosis for individuals with congenital mirror movement disorder varies. While the condition is lifelong, many individuals learn to adapt to the involuntary movements and lead normal lives. The severity of the disorder can vary widely among affected individuals.
Related pages[edit]
External links[edit]
