TypesofSpinalMuscular Atrophy(SMA)andSymptoms
Whatisspinalmuscularatrophy(SMA)?
Nervesignalsareharmedandeventuallydieasaresultofthegeneticillnessesknownas spinalmuscularatrophy(SMA).Inthespinalcordandlowerregionofthebrain,thereisa typeofnervecellcalledamotorneuron.Yourtongue,throat,chest,arms,andlegscanall movethankstothem.
Yourmusclesworsenandatrophyasthemotorneuronsdieoff(wasteaway).Overtime, musclelossgetsworseandmightinterferewithbreathing,walking,talking,and swallowing.
AtopneurologistinChennaisuggestsagroupofgeneticdiseasesthatdamageandkills motorneurons.
Whatkindofspinalmuscularatrophy(SMA)arethere,andwhatsignsandsymptomsdo theyhave?
TherearevariousvarietiesofSMA.Theydependonthedisease'sseverityandthetiming oftheonsetofsymptoms:
● typelIt'sthemosttypicalaswell.Thistypeofbabytypicallydisplaystheillness beforesixmonthsofage.Thewarningsymptomsmightbeseenbeforeorafterbirth inmoreseverecases(Types0or1A).Theinfantsmayhavedifficultybreathingand swallowing,andtheymightnotmovearoundmuch.Theyhavetendonsormuscles thatarechronicallyshort(calledcontractures).Typically,theyneedassistancetosit up.Numerouskidswiththisconditionwillpassawaybeforereceivingtherapy.
● AmoderatetosevereformofSMAistypell.Typically,betweentheagesof6and18 months,itisfirstrecognized.Mostofthesekidscansitunaided,buttheycan'tstand orwalkwithoutassistance.Theymightalsohaverespiratoryissues.Usually,they haveachancetoliveintoadolescenceorearlyadulthood.
AnothernamefortypellIisKugelberg-Welanderillness.Itisthemildestformthat affectschildren.Aftertheageof18months,thediseasetypicallybeginstomanifest itssymptoms.Thesekidscanwalkbythemselves,buttheycouldstruggletorun, standupfromachair,orclimbstairs.Additionally,theycouldhaverespiratory infections,contractures,andscoliosis(spinalcurvature).Mostchildrenwiththis varietywillliveanaveragelifespanwiththerapy.
● TypeIVisuncommonandfrequentlymild.Afterage21,symptomstypicallystartto appear.Thesignsincludetremors,slightrespiratoryissues,andmildtomoderateleg muscleweakness.Overtime,thesymptomsgraduallygetworse.Thosewiththiskind ofSMAexperienceanaveragelifespan.
WhatcauseSMA,orspinalmuscularatrophy?
MostkindsofSMAarecausedbychangesintheSMN1gene.Thisgeneisinchargeof producingaproteinrequiredforthemotorneuron'sgoodhealthandproperoperation. Thereisn'tenoughproteinforthemotorneuronswhenaportionoftheSMN1geneis missingoraberrant,though.Motorneuronsstarttodieasaresultofthis.
TheSM1geneistypicallypresentintwocopies,onefromeachparent.SMAoftenonly occurswhenthegenemutationaffectsbothcopies.Thereusuallyaren'tanysymptomsif themodificationaffectsonlyonecopy.However,mightinheritthatgenefromaparenttoa child.SomelessfrequentSMAformscouldbebroughtonbychangesinothergenes.
ThebestneurologistinChennaitreatsthediseasesofthebrain,peripheralnerves,and musclesspinalmuscularatrophytosavealife.